Treatment for behavioral insomnia in young children with neurotypical development under 6 years of age: A systematic review

This literature review examines all treatments for behavioral insomnia in children under 6 years of age to determine which treatments have empirically demonstrated efficacy. Following PRISMA guidelines, three databases were investigated (Pubmed, Cochrane and Psychinfo) to select randomized controlled trials (RCTs) which assess treatments for behavioral insomnia in children under 6 years of age, all with neurotypical development. A total of 908 articles met the search criteria. 21 articles were selected and analyzed in their entirety for a total of 2363 children (ranging from 2 months to 6 years of age). Based on these studies, treatment of behavioral insomnia in young children under 6 years of age is primarily based on behavioral therapy. There is no evidence that pharmacological treatments are effective in the long term for neurotypical children. This review highlights the lack of RCTs in this field: new RCTs should be carried out among young children to refine and optimize the therapeutic approach and to address the risk of therapeutic abuse through the use of non-scientifically validated methods.

Influenza transmissibility among patients and health-care professionals in a geriatric short-stay unit using individual contact data

Detailed information are lacking on influenza transmissibility in hospital although clusters are regularly reported. In this pilot study, our goal was to estimate the transmission rate of H3N2 2012-influenza, among patients and health care professionals in a short-term Acute Care for the Elderly Unit by using a stochastic approach and a simple susceptible-exposed-infectious-removed model. Transmission parameters were derived from documented individual contact data collected by Radio Frequency IDentification technology at the epidemic peak. From our model, nurses appeared to transmit infection to a patient more frequently with a transmission rate of 1.04 per day on average compared to 0.38 from medical doctors. This transmission rate was 0.34 between nurses. These results, even obtained in this specific context, might give a relevant insight of the influenza dynamics in hospitals and will help to improve and to target control measures for preventing nosocomial transmission of influenza. The investigation of nosocomial transmission of SARS-COV-2 might gain from similar approaches.

Enriched PUFA environment of Leishmania infantum promastigotes promotes the accumulation of lipid mediators and favors parasite infectivity towards J774 murine macrophages

Leishmania parasites are the causative agents of visceral or cutaneous leishmaniasis in humans and of canine leishmaniosis. The macrophage is the predilected host cell of Leishmania in which the promastigote stage is transformed into amastigote. We previously showed changes in the fatty acid composition (FA) of lipids in two strains of Leishmania donovani upon differentiation of promastigote to amastigote, including increased proportions of arachidonic acid (AA) and to a less extent of docosahexaenoic acid (DHA). Here, we carried out supplementation with AA or DHA on two Leishmania infantum strains, a visceral (MON-1) and a cutaneous (MON-24), to evaluate the role of these FA in parasite/macrophage interactions. The proportions of AA or DHA in total lipids were significantly increased in promastigotes cultured in AA- or DHA-supplemented media compared to controls. The content of FA-derived oxygenated metabolites was enhanced in supplemented strains, generating especially epoxyeicosatrienoic acids (11,12- and 14,15-EET) and hydroxyeicosatetraenoic acids (5- and 8- HETE) from AA, and hydroxydocosahexaenoic acids (14- and 17-HDoHE) from DHA. For both MON-1 and MON-24, AA-supplemented promastigotes showed higher infectivity towards J774 macrophages as evidenced by higher intracellular amastigote numbers. Higher infectivity was observed after DHA supplementation for MON-24 but not MON-1 strain. ROS production by macrophages increased upon parasite infection, but only minor change was observed between control and supplemented parasites. We propose that under high AA or DHA environment that is associated with AA or DHA enrichment of promastigote lipids, FA derivatives can accumulate in the parasite, thereby modulating parasite infectivity towards host macrophages.

Trends in the proportion of resistant bacteria involved in ventilator-associated pneumonia as the first hospital-acquired infection in intensive care units between 2003 and 2016 in Lyon, France

The aim of this study was to describe the proportion of multidrug-resistant microorganisms (MDROs) involved in ventilator-associated pneumonia (VAP) as the first hospital-acquired infection in 536 adults with restricted risk factors for MDRO-related infection. We found a significant decrease in the percentage of MDROs involved in VAP between 2003 and 2016 and this percentage increased when VAP occurred after day 10.

Influence of Different Implant Types on Bone Levels After Healing and Peri-implant Tissue Reactions Following Peri-implantitis: A Preclinical Study

This study evaluated the influence of different implant types on (1) radiographic marginal bone levels after healing and (2) radiographic and histomorphometric tissue levels and characteristics following ligature-induced peri-implantitis. Four implant types (Standard Plus, Straumann [S]; NobelReplace Tapered, Nobel Biocare [N]; In-Kone Universal, Global D [I]; and twinKon, Global D [T]) were randomly placed in the edentulous healed mandibular ridge of six dogs (T0), for a total of 57 implants placed. After 10 weeks, a peri-implantitis was ligature-induced (T1). After 12 weeks, biopsy samples were processed for histomorphometric analysis (T2). Standardized radiographs were taken at T0, T1, and T2 for imaging analysis. Statistical analysis was performed using mixed-effects linear modeling. After healing (T1), the radiographic marginal bone level was more coronal for implants I, T, and S compared to N. Following peri-implantitis (T2), the histologic marginal bone level was more coronal for implants I, T, and S compared to N, and for implants I and T compared to S. Also at T2, the radiographic marginal bone level was more coronal at implants I, T, and S compared to N. Implant type may influence bone remodeling during healing and bone loss during the early stages of experimental peri-implantitis.

Development and Cross-National Validation of a French Version of the Jefferson Scale of Empathy for Students

Empathy is a multifaceted personal ability combining emotional and cognitive features modulated by cultural specificities. It is widely recognized as a key clinical competence that should be valued during professional training. The Jefferson Scale of Empathy for medical students (JSE-S) has been developed for this purpose and validated in several languages, but not in French. The aims of this study were to gather validity evidence for a newly developed version of the JSE-S and compare it between two French-speaking contexts. In total, 1,433 undergraduate medical students from the universities of Lyon (UL), France and Geneva (UG), Switzerland participated in the study completing the JSE-S in French. Total and partial scores of the three subscales (“perspective taking,” “compassionate care” and “walking in patient’s shoes”) were calculated for each site. Construct validity of the JSE-S was analyzed considering three sources of evidence: content, internal structure and relations to other variables. A first-order Confirmatory Factor Analysis using structural equation modeling examined the three latent variables of the JSE-S subscales. Cronbach’s α coefficients were 0.75 (UG) and 0.81 (UL). The items’ discrimination power ranged between 0.29 and 1.60 (median effect size of 1.24). The overall correlations between items and total or partial scores derived from the latent JSE-S subscales were consistently similar in both study sites. Findings of this study confirm the latent structure of the JSE-S in French and its cross-national reproducibility. The comparable underlying structure of the questionnaire tested in two distinct French-speaking contexts endorses the generalizability of its measure.

Factors associated with admission to intensive care units in COVID-19 patients in Lyon-France

INTRODUCTION

A new respiratory virus, SARS-CoV-2, has emerged and spread worldwide since late 2019. This study aims at analysing clinical presentation on admission and the determinants associated with admission in intensive care units (ICUs) in hospitalized COVID-19 patients.

PATIENTS AND METHODS

In this prospective hospital-based study, socio-demographic, clinical and biological characteristics, on admission, of adult COVID-19 hospitalized patients presenting from the community for their first admission were prospectively collected and analysed. Characteristics of patients hospitalized in medical ward to those admitted in ICU were compared using Mann-Whitney and Chi-square or Fisher exact test when appropriate. Univariate logistic regression was first used to identify variables on admission that were associated with the outcome i.e. admission to an ICU versus total hospital stay in a medical ward. Forward selection was then applied beginning with sex, age and temperature in the multivariable logistic regression model.

RESULTS

Of the 412 patients included, 325 were discharged and 87 died in hospital. Multivariable regression showed increasing odds of ICU hospitalization with temperature (OR, 1.56 [95% CI, 1.06-2.28] per degree Celsius increase), oxygen saturation <90% (OR, 12.45 [95% CI, 5.27-29.4]), abnormal lung auscultation on admission (OR, 3.58 [95% CI, 1.58-8.11]), elevated level of CRP (OR, 2.7 [95% CI, 1.29-5.66for CRP>100mg/L vs CRP<10mg/L). and monocytopenia (OR, 3.28 [95% CI, 1.4-7.68]) were also associated with increasing odds of ICU hospitalization. Older patients were less likely to be hospitalized in ICU (OR, 0.17 [95%CI, 0.05-0.51].

CONCLUSIONS

Age and delay between onset of symptoms and hospital admission were associated with the risk of hospitalisation in ICU. Age being a fixed variable, interventions that shorten this delay would improve the prognosis of Covid-19 patients.

A Conceptual Discussion About the Basic Reproduction Number of Severe Acute Respiratory Syndrome Coronavirus 2 in Healthcare Settings

To date, no specific estimate of R0 for SARS-CoV-2 is available for healthcare settings. Using interindividual contact data, we highlight that R0 estimates from the community cannot translate directly to healthcare settings, with pre-pandemic R0 values ranging 1.3-7.7 in 3 illustrative healthcare institutions. This has implications for nosocomial COVID-19 control.

Narcolepsy with cataplexy: Does age at diagnosis change the clinical picture?

Objective

To compare symptoms and sleep characteristics in patients diagnosed with narcolepsy‐cataplexy (NC) before and after the age of 18 years.

Methods

De novo patients with NC diagnosis completed a standardized questionnaire and interview, followed by a sleep study. The clinical and sleep measures were compared between patients diagnosed before (46 children, median age: 12 year old) and after (46 adults, median age: 28.5 year old) 18 years of age.

Results

The frequency of obesity (54% vs 17%), night eating (29% vs 7%), parasomnia (89% vs 43%), sleep talking (80% vs 34%), and sleep drunkenness (69% vs 24%) were higher in children than in adults, the frequency of sleep paralysis was lower (20% vs 55%) but the frequency of cataplexy and the severity of sleepiness were not different. Children scored higher than adults at the attention‐deficit/hyperactivity disorder (ADHD) scale. Depressive feelings affected not differently children (24%) and adults (32%). However, adults had lower quality of life than children. There was no difference between groups for insomnia and fatigue scores. Quality of life was essentially impacted by depressive feelings in both children and adults. Obstructive apnea‐hypopnea index (OAHI) was lower in children with higher mean and minimal oxygen saturation than in adults. No between‐group differences were found at the multiple sleep latency test. The body mass index (z‐score) was correlated with OAHI (r = .32).

Conclusion

At time of NC diagnosis, children have more frequent obesity, night eating, parasomnia, sleep talking, drunkenness, and ADHD symptoms than adults, even if sleepiness and cataplexy do not differ. These differences should be considered to ensure a prompt diagnosis.

Association of characteristics of tampon use with menstrual toxic shock syndrome in France

BACKGROUND

Menstrual tampons are widely used in western countries. Indirect evidence suggests that tampon misuse could be associated with an increased risk of menstrual toxic shock syndrome (MTSS). The aim of this study was to determine what characteristics of tampon use are associated with increased risk of menstrual toxic shock syndrome (MTSS).

METHODS

A nationwide, case-control study in France, was conducted with women that use tampons with MTSS diagnoses according to the CDC diagnostic criteria (n = 55, from January 2011, to December 2017) and a control group of women with no MTSS history (n = 126, from February to December 2017). Information regarding tampon use during a 6-month period was collected. Associations between tampon use and MTSS were assessed using logistic regression models stratified by residential area.

FINDINGS

Compared to controls, women diagnosed with MTSS more frequently reported maximum tampon wear of >6 h (62% vs. 41%; P = 0.02), overnight tampon use (77% vs. 54%; P = 0.006), and neither read nor followed tampon instructions in case of reading (65% vs. 42%; P = 0.006). In univariate analysis, MTSS risk was two-fold higher with tampon use for >6 consecutive hours (odds ratio, 2.3 [95% CI, 1.2-4.5]), and three-fold higher with tampon use during sleep for >8 h (odds ratio, 3.2 [95% CI, 1.4-7.7]). In multivariate logistic regression analysis, only maximum tampon use for >6 h (odds ratio, 2.03 [95% CI, 1.04-3.98]), and neither read nor followed the tampon instructions in case of reading (odds ratio, 2.25 [95% CI, 1.15-4.39]) were independently associated with MTSS.

INTERPRETATION

Our study suggests that the risk of MTSS was associated with using tampons for more than 6 h, overnight tampon use during sleep, and neither read nor followed tampon insertion instructions in case of reading.

FUNDING

LABEX ECOFECT (ANR-11-LABX-0048) of Université de Lyon within the programme "Investissements d'Avenir" (ANR-11-IDEX-0007) operated by the French National Research Agency (ANR).

Clinical Evaluation of a Multiplex PCR for the Detection of Salmonella enterica Serovars Typhi and Paratyphi A from Blood Specimens in a High-Endemic Setting

Enteric fever is a major public health concern in endemic areas, particularly in infrastructure-limited countries where Salmonella Paratyphi A has emerged in increasing proportion of cases. We aimed to evaluate a method to detect Salmonella Typhi (S. Typhi) and Salmonella Paratyphi A (S. Paratyphi A) in febrile patients in Bangladesh. We conducted a prospective study enrolling patients with fever > 38°C admitted to two large urban hospitals and two outpatient clinics located in Dhaka, Bangladesh. We developed and evaluated a method combining short culture with a new molecular assay to simultaneously detect and differentiate S. Typhi and S. Paratyphi A from other Salmonella directly from 2 to 4 mL of whole blood in febrile patients (n = 680). A total of 680 cases were enrolled from the four participating sites. An increase in the detection rate (+38.8%) in S. Typhi and S. Paratyphi A was observed with a multiplex polymerase chain reaction (PCR) assay, and absence of non-typhoidal Salmonella detection was reported. All 45 healthy controls were culture and PCR negative, generating an estimated 92.9% of specificity on clinical samples. When clinical performance was assessed in the absence of blood volume prioritization for testing, a latent class model estimates clinical performance ≥ 95% in sensitivity and specificity with likelihood ratio (LR) LR+ > 10 and LR− < 0.1 for the multiplex PCR assay. The alternative method to blood culture we developed may be useful alone or in combination with culture or serological tests for epidemiological studies in high disease burden settings and should be considered as secondary endpoint test for future vaccine trials.

Investigation of the Relationships Between Clinical and Environmental Isolates of Aspergillus fumigatus by Multiple-locus Variable Number Tandem Repeat Analysis During Major Demolition Work in a French Hospital

Background

Genotyping is needed to explore the link between clinical cases from colonization of invasive aspergillosis (IA) and major building construction. Attempts to correlate Aspergillus fumigatus strains from clinical infection or colonization with those found in the environment remain controversial due to the lack of a large prospective study. Our aim in this study was to compare the genetic diversity of clinical and environmental A. fumigatus isolates during a demolition period.

Methods

Fungal contamination was monitored daily for 11 months in 2015. Environmental surveillance was undertaken indoors and outdoors at 8 locations with automatic agar samplers. IA infection cases were investigated according to European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria. Isolates were identified by amplification and sequencing of the β- tubulin gene. They were genotyped by multiple-locus variable number tandem repeat analysis (MLVA). The phylogenetic relationships between isolates were assessed by generating a minimum spanning tree.

Results

Based on 3885 samples, 394 A. fumigatus isolates (383 environmental and 11 clinical) were identified and genotyped using MLVA. Clinical isolates were collected from patients diagnosed as having probable IA (n = 2), possible IA (n = 1), or bronchial colonization (n = 6). MLVA generated 234 genotypes. Seven clinical isolates shared genotypes identical to environmental isolates.

Conclusions

Among the diversity of genotypes described, similar genotypes were found in clinical and environmental isolates, indicating that A. fumigatus infection and colonization may originate from hospital environments.

Integrated problem-based learning versus lectures: a path analysis modelling of the relationships between educational context and learning approaches

Students' approaches to learning are central to the process of learning. Previous research has revealed that influencing students' approaches towards deep learning is a complex process and seems much more difficult than expected, even in student-activating learning environments. There is evidence that learning approaches are impacted not only by the learning environment, but also by how students perceive it. However the nature of the links between the environment itself, the way in which it is perceived by students and students' learning approaches is poorly understood. This study aimed at investigating the relationships between students' perception of their educational context and learning approaches in three learning environments differing by their teaching formats (lecture or problem-based-learning PBL) and integration level of the curriculum (traditional or integrated). We tested the hypothesis that a PBL format and an integrated curriculum are associated to deeper approaches to learning and that this is mediated by student perception. The study sample was constituted of 1394 medical students trained respectively in a traditional lecture-based (n = 295), in an integrated lecture-based (n = 612) and in an integrated PBL-based (n = 487) curricula. They completed a survey including the Dundee-Ready-Educational-Environment-Measure (students' perceptions of the educational environment) and the Revised-Study-Process-Questionnaire (learning approaches). Data were analysed by path analysis. The model showed that the learning environment was related to students' learning approaches by two paths, one direct and one mediated via students' perception of their educational context. In the lecture-based curricula students' used deeper approaches when it was integrated and both paths were cumulative. In the PBL-based curriculum students' did not use deeper approaches than with lectures, due to opposite effects of both paths. This study suggested that an integrated lecture-based curriculum was as effective as a PBL curriculum in promoting students' deep learning approaches, reinforcing the importance of integrating the curriculum before choosing the teaching format.

ITPA Activity in Children Treated by Azathioprine: Relationship to the Occurrence of Adverse Drug Reactions and Inflammatory Response

Azathioprine (AZA), a thiopurine drug, is widely used in the treatment of children with immunological diseases such as inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH); however, interindividual variability in the occurrence of adverse drug reactions (ADRs) and drug response is observed. This study investigated (i) the relationships between inosine triphosphate pyrophosphatase (ITPA) activity, an enzyme involved in thiopurine metabolism, and the occurrence of ADRs in children with immunological disease on AZA therapy, and (ii) the relationship between ITPA activity and the inflammatory activity observed in children with IBD. ITPA and TPMT activities were determined in 106 children with immunological disease on AZA therapy. Markers of hepatotoxicity, myelotoxicity, pancreatitis and inflammation as well as clinical information were retrospectively collected during regular medical visits. No significant association was found between ITPA activity and hepatotoxicity or clinical ADRs such as cutaneous reactions, arthralgia, flulike symptoms and gastrointestinal disorders. Concerning myelotoxicity, a significant relation was observed between ITPA activity and RBC mean corpuscular volume (MCV; p=0.003). This observation may be related to the significant relationship found between high ITPA activity and the increase in γ-globulin level reflecting inflammation (p=0.005). In our study, ITPA activity was not associated with occurrence of ADRs, but a relationship between high ITPA activity and γ-globulin, a marker of inflammation, was found in children with IBD. Therefore, measurement of ITPA activity may help to identify children with IBD predisposed to residual inflammation on AZA therapy. Further prospective studies are needed to confirm this result.

Evaluation of Hirst-type spore traps in outdoor Aspergillaceae monitoring during large demolition work in hospital

Demolition can generate fungal spore suspensions in association with various adverse health effects, such as high risk of invasive aspergillosis in immunocompromised patients. One block of Edouard Herriot Hospital was entirely demolished. The aim of the present study was to evaluate Hirst-type spore traps utility in monitoring outdoor Aspergillaceae (Aspergillus spp. + Penicillium spp.) spores in part of Edouard Herriot Hospital (Lyon, France) undergoing major demolition. Three periods were scheduled in 2015: (A) Gutting of building and asbestos removal, (B) Demolition of floors, (C) Excavation and earthwork. Outdoor Aspergillaceae fungal load was monitored by cultivable (Air Ideal®, bioMérieux) and non-cultivable methods (Lanzoni VPPS-2000, Analyzair®, Bologna, Italy). Differences of Aspergillaceae recorded with Hirst-type spore traps were observed between Gerland and Edouard Herriot Hospital. Differences between Aspergillaceae were recorded between day time and night time at Gerland and Edouard Herriot Hospital. Daily paired differences between Aspergillaceae recorded with non-cultivable methodology at Edouard Herriot Hospital and in an area without demolition work were significant in Period A vs Period B (p = 10–4) and Period A vs Period C (p = 10–4). Weak correlation of daily Aspergillaceae recorded by both methods at Edouard Herriot Hospital was significant only for Period C (r = 0.26, p = 0.048, n = 58). Meteorological parameters and type of demolition works were found to heavily influenced Aspergillaceae dispersion. Non-cultivable methodology is a promising tool for outdoor Aspergillaceae scrutiny during major demolition work in hospital, helping infection control staff to rapidly implement control measures.

Monitoring of clinical strains and environmental fungal aerocontamination to prevent invasive aspergillosis infections in hospital during large deconstruction work: a protocol study

INTRODUCTION

Monitoring fungal aerocontamination is an essential measure to prevent severe invasive aspergillosis (IA) infections in hospitals. One central block among 32 blocks of Edouard Herriot Hospital (EHH) was entirely demolished in 2015, while care activities continued in surrounding blocks. The main objective was to undertake broad environmental monitoring and clinical surveillance of IA cases to document fungal dispersion during major deconstruction work and to assess clinical risk.

METHODS AND ANALYSIS

A daily environmental survey of fungal loads was conducted in eight wards located near the demolition site. Air was collected inside and outside selected wards by agar impact samplers. Daily spore concentrations were monitored continuously by volumetric samplers at a flow rate of 10 L.min^-1. Daily temperature, wind direction and speed as well as relative humidity were recorded by the French meteorological station Meteociel. Aspergillus fumigatus strains stored will be genotyped by multiple-locus, variable-number, tandem-repeat analysis. Antifungal susceptibility will be assessed by E-test strips on Roswell Park Memorial Institute medium supplemented with agar. Ascertaining the adequacy of current environmental monitoring techniques in hospital is of growing importance, considering the rising impact of fungal infections and of curative antifungal costs. The present study could improve the daily management of IA risk during major deconstruction work and generate new data to ameliorate and redefine current guidelines.

ETHICS AND DISSEMINATION

This study was approved by the clinical research and ethics committees of EHH.

Use of surveillance data to calculate the sample size and the statistical power of randomized clinical trials testing Staphylococcus aureus vaccine efficacy in orthopedic surgery

BACKGROUND

Patients undergoing primary total hip arthroplasty (THA) would be a worthy population for anti-staphylococcal vaccines. The objective is to assess sample size for significant vaccine efficacy (VE) in a randomized clinical trial (RCT).

METHODS

Data from a surveillance network of surgical site infection in France between 2008 and 2011 were used. The outcome was S. aureus SSI (SASSI) within 30 days after surgery. Statistical power was estimated by simulations repeated for theoretical VE ranging from 20% to 100% and for sample sizes from 250 to 8000 individuals per arm.

RESULTS

18,688 patients undergoing THA were included; 66 (0.35%) SASSI occurred. For a 1% SASSI rate, the sample size would be at least 1316 patients per arm to detect significant VE of 80% with 80% power.

CONCLUSION

Simulations with real-life data from surveillance of hospital acquired infections allow estimation of power for RCT and sample size to reach the required power.

Evaluation of hirst-type spore trap to monitor environmental fungal load in hospital

The main purpose was to validate the use of outdoor-indoor volumetric impaction sampler with Hirst-type spore traps (HTSTs) to continuously monitor fungal load in order to prevent invasive fungal infections during major structural work in hospital settings. For 4 weeks, outdoor fungal loads were quantified continuously by 3 HTSTs. Indoor air was sampled by both HTST and viable impaction sampler. Results were expressed as particles/m³ (HTST) or colony-forming units (CFU)/m³ (biocollector). Paired comparisons by day were made with Wilcoxon’s paired signed-rank test or paired Student’s t-test as appropriate. Paired airborne spore levels were correlated 2 by 2, after log-transformation with Pearson’s cross-correlation. Concordance was calculated with kappa coefficient (κ). Median total fungal loads (TFLs) sampled by the 3 outdoor HTSTs were 3,025.0, 3,287.5 and 3,625.0 particles/m³ (P = 0.6, 0.6 and 0.3).—Concordance between Aspergillaceae fungal loads (AFLs, including Aspergillus spp. + Penicillium spp.) was low (κ = 0.2). A low positive correlation was found between TFLs sampled with outdoor HTST and indoor HTST with applying a 4-hour time lag, r = 0.30, 95% CI (0.23–0.43), P<0.001. In indoor air, Aspergillus spp. were detected by the viable impaction sampler on 63.1% of the samples, whereas AFLs were found by HTST-I on only 3.6% of the samples. Concordance between Aspergillus spp. loads and AFLs sampled with the 2 methods was very low (κ = 0.1). This study showed a 4-hour time lag between increase of outdoor and indoor TFLs, possibly due to insulation and aeraulic flow of the building. Outdoor HTSTs may permit to quickly identify (after 48 hours) time periods with high outdoor fungal loads. An identified drawback is that a too low sample area read did not seem to enable detection of Aspergillaceae spores efficiently. Indoor HTSTs may not be recommended at this time, and outdoor HTSTs need further study. Air sampling by viable impaction sampler remains the reference tool for quantifying fungal contamination of indoor air in hospitals.

Lost in Transit: Long-Distance Trafficking and Phloem Unloading of Protein Signals in Arabidopsis Homografts

In addition to moving sugars and nutrients, the phloem transports many macromolecules. While grafting and aphid stylectomy experiments have identified many macromolecules that move in the phloem, the functional significance of phloem transport of these remains unclear. To gain insight into protein trafficking, we micrografted Arabidopsis thaliana scions expressing GFP-tagged chloroplast transit peptides under the 35S promoter onto nontransgenic rootstocks. We found that plastids in the root tip became fluorescent 10 d after grafting. We obtained identical results with the companion cell-specific promoter SUC2 and with signals that target proteins to peroxisomes, actin, and the nucleus. We were unable to detect the respective mRNAs in the rootstock, indicating extensive movement of proteins in the phloem. Outward movement from the root protophloem was restricted to the pericycle-endodermis boundary, identifying plasmodesmata at this interface as control points in the exchange of macromolecules between stele and cortex. Intriguingly, signals directing proteins to the endoplasmic reticulum and Golgi apparatus from membrane-bound ribosomes were not translocated to the root. It appears that many organelle-targeting sequences are insufficient to prevent the loss of their proteins into the translocation stream. Thus, nonspecific loss of proteins from companion cells to sieve elements may explain the plethora of macromolecules identified in phloem sap.

Relearn Faster and Retain Longer

Both repeated practice and sleep improve long-term retention of information. The assumed common mechanism underlying these effects is memory reactivation, either on-line and effortful or off-line and effortless. In the study reported here, we investigated whether sleep-dependent memory consolidation could help to save practice time during relearning. During two sessions occurring 12 hr apart, 40 participants practiced foreign vocabulary until they reached a perfect level of performance. Half of them learned in the morning and relearned in the evening of a single day. The other half learned in the evening of one day, slept, and then relearned in the morning of the next day. Their retention was assessed 1 week later and 6 months later. We found that interleaving sleep between learning sessions not only reduced the amount of practice needed by half but also ensured much better long-term retention. Sleeping after learning is definitely a good strategy, but sleeping between two learning sessions is a better strategy.

Soft Tissue and Marginal Bone Adaptation on Platform-Switched Implants with a Morse Cone Connection: A Histomorphometric Study in Dogs

The purpose of this study was to investigate peri-implant tissue adaptation on platform-switched implants with a Morse cone-type connection, after 3 and 12 weeks of healing in dogs. Ten weeks after mandibular premolar extractions, eight beagle dogs received three implants each. At each biopsy interval, four animals were sacrificed and biopsies were processed for histologic analysis. The height of the peri-implant mucosa was 2.32 mm and 2.88 mm, respectively, whereas the bone level in relation to the implant platform was -0.39 mm and -0.67 mm, respectively, after 3 and 12 weeks of healing. Within the limits of the present study, platform-switched implants exhibited reduced values of biologic width and marginal bone loss when compared with previous data.

High bicarbonate levels in narcoleptic children

The objective of this study was to evaluate the levels of plasma bicarbonate levels in narcoleptic children. Clinical, electrophysiological data and bicarbonate levels were evaluated retrospectively in children seen in our paediatric national reference centre for hypersomnia. The cohort included 23 control subjects (11.5 ± 4 years, 43% boys) and 51 patients presenting de-novo narcolepsy (N) (12.7 ± 3.7 years, 47% boys). In narcoleptic children, cataplexy was present in 78% and DQB1*0602 was positive in 96%. The control children were less obese (2 versus 47%, P = 0.001). Compared with control subjects, narcoleptic children had higher bicarbonate levels (P = 0.02) as well as higher PCO2 (P < 0.01) and lower venous pH gas (P < 0.01). Bicarbonate levels higher than 27 mmol L(-1) were found in 41.2% of the narcoleptic children and 4.2% of the controls (P = 0.001). Bicarbonate levels were correlated with the Adapted Epworth Sleepiness Scale (P = 0.01). Narcoleptic patients without obesity often had bicarbonate levels higher than 27 mmol L (-1) (55 versus 25%, P = 0.025). No differences were found between children with and without cataplexy. In conclusion, narcoleptic patients had higher bicarbonate plasma levels compared to control children. This result could be a marker of hypoventilation in this pathology, provoking an increase in PCO2 and therefore a respiratory acidosis, compensated by an increase in plasma bicarbonates. This simple screening tool could be useful for prioritizing children for sleep laboratory evaluation in practice.

Use of surveillance data to identify target populations for Staphylococcus aureus vaccines and prevent surgical site infections: a pilot study

The development of anti-staphylococcal vaccines is nowadays a priority to prevent surgical site infections (SSI). The objective of the present study was to identify a potential target population by assessing surveillance data on surgery patients for possible anti-staphylococcal vaccine administration. Individuals at high risk of SSI by Staphylococcus aureus (SA) were targeted by the French SSI Surveillance Network in south-eastern France between 2008 and 2011. Among 238,470 patients, those undergoing primary total hip replacement appeared to be an interesting and healthy enough population for anti-staphylococcal vaccine testing. These male patients, subjected to multiple procedures and with American Society of Anesthesiologists score>2, had a probability of SA SSI about 21 times higher than females with no severe systemic disease and no multiple procedures. Our study indicates that surveillance data on SSI might be an interesting epidemiological source for planning vaccine trials to prevent nosocomial infections.

Robust coordination of cardiac functions from gene co-expression reveals a versatile combinatorial transcriptional control

The necessary overall coordination of cardiac cellular functions is little known at the mRNA level. Focusing on energy production and cardiac contraction, we analyzed microarray data from heart tissue obtained in groups of mice and rats in normal conditions and with a left ventricular dysfunction. In each group and for each function, we identified genes positively or negatively correlated with numerous genes of the function, which were called coordinated or inversely coordinated with the function. The genes coordinated with energy production or cardiac contraction showed the coupling of these functions in all groups. Among coordinated or inversely coordinated genes common to the two functions, we proposed a fair number of transcriptional regulators as potential determinants of the energy production and cardiac contraction coupling. Although this coupling was constant across the groups and unveiled a stable gene core, the combinations of transcriptional regulators were very different between the groups, including one half that has never been linked to heart function. These results highlighted the stable coordination of energy production or cardiac contraction at the mRNA level, and the combinatorial and versatile nature of potential transcriptional regulation. In addition, this work unveiled new transcriptional regulators potentially involved in normal or altered cardiac functional coupling.

Quality of life in children with narcolepsy

AIMS

To evaluate the health-related quality of life (HRQL) and its correlates in children and adolescents with narcolepsy.

METHODS

We compared the clinical characteristics of control subjects and patients with primary narcolepsy from data collected at the National Reference Centers for Narcolepsy.

RESULTS

The cohort included 69 control subjects (29 boys) and 117 patients (65 boys; 59 de novo patients). Cataplexy was present in 81% and DQB1*0602 was positive in 91%. The control children were older (13.5±3.2 vs. 11.6±3.1 years, P<0.001) and less obese (1.4% vs. 60%, P<0.001). Twenty-five percent of the patients and 15.6% of the control subjects had clinically significant depressive feelings on Children's Depression Inventory (CDI≥16) (NS). Fifty-three narcoleptic and 43 control adolescents, 31 narcoleptic children and 23 control children filled out the HRQL questionnaires as well as 83 parents of patients and 60 parents of control subjects. Narcolepsy seriously impacts HRQL in terms of vitality, physical well-being, relations with friends and leisure activities, especially in adolescents. Depression was the factor that most affected HRQL in both narcoleptic and control subjects. For the control subjects and the narcoleptic patients, when the CDI score was entered into the multivariable regression model adjusted for gender and age, no other continuous independent variable could significantly increase the likelihood of the model. When the CDI score increased by 1, the mean HRQL score decreased by 1.7 for narcoleptic patients and 1.5 for control subjects. Apnea-hypopnoea index, diagnosis delay, disease duration, obesity, the presence of cataplexy or treatment had no effects on HRQL.

CONCLUSIONS

Narcoleptic children and adolescents were at high risk for poor HRQL. Depressive symptoms had a major impact on HRQL. We recommend a more thorough assessment and management of psychological health in this population.

Computational identification of potential transcriptional regulators of TGF-ß1 in human atherosclerotic arteries

TGF-ß is protective in atherosclerosis but deleterious in metastatic cancers. Our aim was to determine whether TGF-ß transcriptional regulation is tissue-specific in early atherosclerosis. The computational methods included 5 steps: (i) from microarray data of human atherosclerotic carotid tissue, to identify the 10 best co-expressed genes with TGFB1 (TGFB1 gene cluster), (ii) to choose the 11 proximal promoters, (iii) to predict the TFBS shared by the promoters, (iv) to identify the common TFs co-expressed with the TGFB1 gene cluster, and (v) to compare the common TFs in the early lesions to those identified in advanced atherosclerotic lesions and in various cancers. Our results show that EGR1, SP1 and KLF6 could be responsible for TGFB1 basal expression, KLF6 appearing specific to atherosclerotic lesions. Among the TFs co-expressed with the gene cluster, transcriptional activators (SLC2A4RG, MAZ) and repressors (ZBTB7A, PATZ1, ZNF263) could be involved in the fine-tuning of TGFB1 expression in atherosclerosis.

Impact of obesity in children with narcolepsy

AIMS

To evaluate the impact of obesity on clinical and sleep characteristics in a population of narcoleptic children.

METHODS

Data from the children diagnosed with idiopathic narcolepsy in the National Reference Centers for Narcolepsy were collected between 2008 and 2011. Clinical and electrophysiological characteristics were compared between obese (body mass index [BMI] greater than P97) and nonobese children.

RESULTS

The 117 children (65 boys, 59 de novo patients) had a mean age of 11.6 ± 3.1 years on diagnosis. Cataplexy was present in 81%, DQB1*0602 in 91%. Mean BMI was 23.2 ± 5.2 kg/m(2) and BMI z-score was 2.9 ± 2.6. Obesity was found in 60% with a similar prevalence in treated versus de novo patients and in patients with and without cataplexy. Sleepiness and cataplexy started earlier in obese children. Obese narcoleptic children had lower sleep efficiency, higher apnea hypopnea index and respiratory arousals index (RAI) than nonobese children. BMI z-score was positively correlated with RAI. Obese children were more tired and missed more often school than nonobese children.

CONCLUSION

Obesity affects more than 50% of narcoleptic children, mostly younger at disease onset, and has a deleterious impact on sleep quality as well as on school attendance.

A graphical method to assess distribution assumption in group-based trajectory models

Group-based trajectory models had a rapid development in the analysis of longitudinal data in clinical research. In these models, the assumption of homoscedasticity of the residuals is frequently made but this assumption is not always met. We developed here an easy-to-perform graphical method to assess the assumption of homoscedasticity of the residuals to apply especially in group-based trajectory models. The method is based on drawing an envelope to visualize the local dispersion of the residuals around each typical trajectory. Its efficiency is demonstrated using data on CD4 lymphocyte counts in patients with human immunodeficiency virus put on antiretroviral therapy. Four distinct distributions that take into account increasing parts of the variability of the observed data are presented. Significant differences in group structures and trajectory patterns were found according to the chosen distribution. These differences might have large impacts on the final trajectories and their characteristics; thus on potential medical decisions. With a single glance, the graphical criteria allow the choice of the distribution that best capture data variability and help dealing with a potential heteroscedasticity problem.

Critical study of observation of the sternal end of the right 4th rib

Studies of the method of estimating age at death by the 4th rib exclusively concerned the phase method without fundamentally challenging the method as such. The present study analyzed observation of the variables on which the Işcan method is based. Ten observers made two assessments of the stage of pit depth, pit shape, rim and wall configurations of 59 right 4th ribs harvested from males (mean age: 49 years; range: 47-94 years). Observation showed poor reproducibility and repeatability for all three variables (Wilcoxon test, kappa-coefficient). Analysis of problem ribs revealed difficulty in measuring and imprecision in describing pit depth and failure to take account of continual aging for the other two variables. Despite these results, Işcan's variables provide objective information on age at death. It is recommended that the method be improved by better description of the variables and use of multivariate statistical analysis.

The microRNA signature in response to insulin reveals its implication in the transcriptional action of insulin in human skeletal muscle and the role of a sterol regulatory element-binding protein-1c/myocyte enhancer factor 2C pathway

OBJECTIVE

Factors governing microRNA expressions in response to changes of cellular environment are still largely unknown. Our aim was to determine whether insulin, the major hormone controlling whole-body energy homeostasis, is involved in the regulation of microRNA expressions in human skeletal muscle.

RESEARCH DESIGN AND METHODS

We carried out comparative microRNA (miRNA) expression profiles in human skeletal muscle biopsies before and after a 3-h euglycemic-hyperinsulinemic clamp, with TaqMan low-density arrays. Then, using DNA microarrays, we determined the response to insulin of the miRNA putative target genes in order to determine their role in the transcriptional action of insulin. We further characterized the mechanism of action of insulin on two representative miRNAs, miR-1 and miR-133a, in human muscle cells.

RESULTS

Insulin downregulated the expressions of 39 distinct miRNAs in human skeletal muscle. Their potential target mRNAs coded for proteins that were mainly involved in insulin signaling and ubiquitination-mediated proteolysis. Bioinformatic analysis suggested that combinations of different downregulated miRNAs worked in concert to regulate gene expressions in response to insulin. We further demonstrated that sterol regulatory element-binding protein (SREBP)-1c and myocyte enhancer factor 2C were involved in the effect of insulin on miR-1 and miR-133a expression. Interestingly, we found an impaired regulation of miRNAs by insulin in the skeletal muscle of type 2 diabetic patients, likely as consequences of altered SREBP-1c activation.

CONCLUSIONS

This work demonstrates a new role of insulin in the regulation of miRNAs in human skeletal muscle and suggests a possible implication of these new modulators in insulin resistance.

Functional meta-analysis of double connectivity in gene coexpression networks in mammals

In functional genomics, the high-throughput methods such as microarrays 1) allow analysis of the relationships between genes considering them as elements of a network and 2) lead to biological interpretations thanks to Gene Ontology. But up to now it has not been possible to find relationships between the functions and the connectivity of the genes in coexpression networks. To achieve this aim, we have defined a double connectivity for each gene by the numbers of its significant negative and positive correlations with the other genes within a given biological condition, or group. Here, based on the analysis of 1,260 DNA microarrays, we show that this double connectivity clearly separates two types of genes, those with a predominantly strong negative connectivity, hub- genes, and those with a predominantly strong positive connectivity, hub+ genes. Interestingly, the hub+ genes concerned transcription factors more often than by chance and, similarly, for the hub- genes concerning miRNA predicted targets. Furthermore, a meta-analysis of GO annotations carried out on 67 groups in humans and rats shows that these two types of genes correspond to a functional biological duality. The hub- genes were mainly involved in basic functions common to all eukaryote cells, whereas the hub+ genes were mainly involved in specialized functions related to cell differentiation and communication. The separation and the biological role of these hub- and hub+ genes provide a powerful new tool for a better understanding of the control and regulation of the key genes involved in cellular differentiation and physiopathological conditions.

Transcriptional alterations in the left ventricle of three hypertensive rat models

Left ventricular hypertrophy (LVH) is commonly associated with hypertension and represents an independent cardiovascular risk factor. The aim of this study was to test the hypothesis that the cardiac overload related to hypertension is associated to a specific gene expression pattern independently of genetic background. Gene expression levels were obtained with microarrays for 15,866 transcripts from RNA of left ventricles from 12-wk-old rats of three hypertensive models [spontaneously hypertensive rat (SHR), Lyon hypertensive rat (LH), and heterozygous TGR(mRen2)27 rat] and their respective controls. More than 60% of the detected transcripts displayed significant changes between the three groups of normotensive rats, showing large interstrain variability. Expression data were analyzed with respect to hypertension, LVH, and chromosomal distribution. Only four genes had significantly modified expression in the three hypertensive models among which a single gene, coding for sialyltransferase 7A, was consistently overexpressed. Correlation analysis between expression data and left ventricular mass index (LVMI) over all rats identified a larger set of genes whose expression was continuously related with LVMI, including known genes associated with cardiac remodeling. Positioning the detected transcripts along the chromosomes pointed out high-density regions mostly located within blood pressure and cardiac mass quantitative trait loci. Although our study could not detect a unique reprogramming of cardiac cells involving specific genes at early stage of LVH, it allowed the identification of some genes associated with LVH regardless of genetic background. This study thus provides a set of potentially important genes contained within restricted chromosomal regions involved in cardiovascular diseases.

Beat-to-beat stroke volume estimation from aortic pressure waveform in conscious rats: comparison of models

Several methods for estimating stroke volume (SV) were tested in conscious, freely moving rats in which ascending aortic pressure and cardiac flow were simultaneously (beat-to-beat) recorded. We compared two pulse-contour models to two new statistical models including eight parameters extracted from the pressure waveform in a multiple linear regression. Global as well as individual statistical models gave higher correlation coefficients between estimated and measured SV (model 1, r = 0.97; model 2, r = 0.96) than pulse-contour models (model 1, r = 0.83; model 2, r = 0.91). The latter models as well as statistical model 1 used the pulsatile systolic area and thus could be applied to only 47 +/- 17% of the cardiac beats. In contrast, statistical model 2 used the pressure-increase characteristics and was therefore established for all of the cardiac beats. The global statistical model 2 applied to data sets independent of those used to establish the model gave reliable SV estimates: r = 0.54 +/- 0.07, a small bias between -8% to +10%, and a mean precision of 7%. This work demonstrated the limits of pulse-contour models to estimate SV in conscious, unrestrained rats. A multivariate statistical model using eight parameters easily extracted from the aortic waveform could be applied to all cardiac beats with good precision.

Mental stress-induced increase in blood pressure is not related to baroreflex sensitivity in middle-aged healthy men

The baroreflex that acts to blunt blood pressure (BP) variations through opposite variations in heart rate should limit the BP increase produced by an emotional challenge. However, relations between baroreflex sensitivity and BP reactivity induced by a psychological stress in a large group of adults have never been firmly established. In 280 healthy men, rest (10 minutes) and stress (5 minutes) BP and heart rate were recorded beat to beat by a blood pressure monitor. The mental stress was elicited by a well-standardized computerized version of a word color conflict stress test (Stroop Color Test). Rest and stress baroreflex sensitivity was assessed by the cross-spectral analysis of BP and heart rate and by the sequence method. The stress-induced increase in systolic BP (22.4+/-0.1 mm Hg) was not correlated with resting baroreflex sensitivity but was slightly correlated (r=0.2, P<0.001) with BP variability assessed either by standard deviation or by mid-frequency band spectral power. Our results suggested that a centrally mediated sympathetic stimulation overcame cardiac autonomic regulation and emphasized the role of the sympathetic vasoconstriction in the pressure response at the onset of the stressing stimulation. During the sustained sympathoexcitatory phase, the cardiac baroreflex blunts BP variations but at a lower sensitivity.

Noninvasive exploration of cardiac autonomic neuropathy. Four reliable methods for diabetes?

OBJECTIVE

The purpose of this work was to assess relevant information that could be provided by various mathematical analyses of spontaneous blood pressure (BP) and heart rate (HR) variabilities in diabetic cardiovascular neuropathy.

RESEARCH DESIGN AND METHODS

There were 10 healthy volunteers and 11 diabetic subjects included in the study. Diabetic patients were selected for nonsymptomatic orthostatic hypotension in an assessment of their cardiovascular autonomic impairment. Cardiac autonomic function was scored according to Ewing's methodology adapted to the use of a Finapres device. The spontaneous beat-to-beat BP and HR variabilities were then analyzed on a 1-h recording in supine subjects. The global variabilities were assessed by standard deviation, fractal dimension, and spectral power. The cardiac baroreflex function was estimated by cross-spectral sequences and Z analyses.

RESULTS

In diabetic patients, Ewing's scores ranged from 1 to 4.5, confirming cardiovascular autonomic dysfunction. In these diabetic patients, global indices of variabilities were consistently lower than in healthy subjects. Furthermore, some of them (standard deviation and fractal dimension of HR, spectral power of systolic blood pressure and HR) were significantly correlated with the Ewing's scores. The Z methods and the spectral analysis found that the cardiac baroreflex was less effective in diabetic subjects. However, the baroreflex sensitivity could not be reliably assessed in all the patients. The sequence method pointed out a decreased number of baroreflex sequences in diabetic subjects that was correlated to the Ewing's score.

CONCLUSIONS

Indices of HR spontaneous beat-to-beat variability are consistently related to the degree of cardiac autonomic dysfunction, according to Ewing's methodology. The Z method and spectral analysis confirmed that the cardiac baroreflex was impaired in diabetic patients. These methods might be clinically relevant for use in detecting incipient neuropathy in diabetic patients.

Identification of spontaneous cardiac baroreflex episodes at different timescales in rats

To study spontaneous cardiac baroreflex at different timescales, a new method has been developed that identifies such episodes. Mean arterial pressure (MAP) and heart rate (HR) were recorded beat to beat over 1 h in freely moving control (n = 10) and acutely (1 day before study, n = 7) and chronically (2 wk before study, n = 10) sinoaortic-denervated (SAD) 12- to 14-wk-old male Sprague-Dawley rats. These beat-to-beat time series were successively low-pass filtered seven times and resampled at different time intervals from 0.1 to 6.4 s, allowing different timescales to be scanned. With the use of the Z coefficient, the statistical relationship was estimated for the associations of inverse MAP and HR variations when these inverse MAP and HR variations occurred simultaneously or were time shifted. In control rats and for timescales > or = 0.4 s, the highest Z coefficient (0.38) was obtained when MAP variations preceded inverse HR variations by one sampling interval. The baroreflex origin of this link was demonstrated by its disappearance after acute SAD. In conclusion, this method enabled spontaneous baroreflex episodes to be identified for unusually long timescales without limiting the study to fast, linear, stationary, or oscillating phenomena.

Beat-to-beat estimation of windkessel model parameters in conscious rats

A windkessel model was applied on a beat-to-beat basis to evaluate the arterial mechanical characteristics in seven conscious rats. Ascending aortic arterial pressure (AP) and blood flow were recorded during steady-state in basal conditions, during infusions of isoprenaline, sodium nitroprusside, and phenylephrine, and after intravenous atenolol injection. For each cardiac cycle the exponential decay time constant (tau) was estimated from the aortic AP curve, peripheral resistances (R) were taken as the ratio of mean AP to cardiac output, and systemic arterial compliance (C) was calculated as tau/R. In all conditions, mean correlation coefficients of the exponential regression and approximately 70% of values in each rat were > 0.99, demonstrating the model validity. In all conditions tau and C exhibited a large spontaneous variability over time, and beat-to-beat correlations were high between tau and C (0.83 +/- 0.03). C was increased by sodium nitroprusside, decreased by isoprenaline, but not significantly decreased by phenylephrine [5.1 +/- 0.2, 3.2 +/- 0.3, and 3.9 +/- 0.2 microliters/mmHg, respectively, vs. 4.2 +/- 0.3 microliters/mmHg (baseline)]. In conclusion, the windkessel model enables tau and C to be reliably estimated in conscious rats during spontaneous and drug-induced hemodynamic variations.

Spontaneous cardiac baroreceptor reflex and regional circulations in conscious rats

OBJECTIVE

To determine the relationships between the activity of the spontaneous cardiac baroreceptor reflex (BRX) and regional vascular dynamics in conscious unrestrained rats.

DESIGN

Simultaneous beat-to-beat recordings of blood pressure and measurements of indices of mesenteric and hindquarters blood flows were performed in seven male normotensive conscious rats under baseline conditions during 1 h.

METHODS

The relationships between systolic blood pressure (SBP) and heart rate were examined using a computerized method, giving the degree of statistical dependence between values of the two parameters with the Z coefficient. This analysis permitted detection of cardiac beats related to cardiac BRX activity. Z analysis was also applied to SBP and to mesenteric or hindquarters blood flow or vascular resistance. Time-series representations were used to describe the chronological patterns corresponding to BRX spontaneous activity.

RESULTS

In these rats, which presented spontaneous BRX-like patterns manifested by the Z analysis, BRX was active during approximately 15% of the time. For 80% of these patterns, cardiac BRX acted to buffer falls in SBP. These depressor events were preceded by muscular vasodilations whereas vasodilations in the mesentery were delayed. Z analysis of these spontaneous haemodynamic patterns confirmed that muscular vasodilations were strongly associated with falls in SBP, whereas vasodilations lagged behind SBP by about seven beats and were not dependent on simultaneous SBP values.

CONCLUSIONS

The Z method showed that spontaneous hindquarters vasodilations were associated with cardiac BRX patterns and that mesenteric vasodilations were not concomitant with falls in SBP and may be the consequence either of a delayed central response or of a local mechanism such as myogenic autoregulation.

[Comparison of three methods for the estimation of spontaneous cardiac baroreflex sensitivity in normotensive and hypertensive subjects]

This study aimed at comparing estimations of spontaneous cardiac baroreflex sensitivity (BRS) obtained with 3 different methods from continuous non-invasive blood pressure recordings in humans. A new method, allowing the quantification of the statistical dependence between values of 2 parameters (Z coefficient), was applied to beat-to-beat systolic blood pressure (SBP) and heart period (HP) values. SBP and HP values with positive Z coefficient and corresponding to baroreflex activity (SBP and HP values both lower or higher than the modal values) were submitted to a linear regression and the regression coefficient (Zgain) was taken as an index of BRS. Second, cross-spectral analysis of SBP and HP gave a BRS value (Csgain) computed as the average value of transfer function moduli for frequencies between 0.07 and 0.14 Hz, with coherence between SBP and HP greater than 0.5. The third method relies on the analysis of linear sequences (r > 0.97) containing at least 3 values of SBP and HP varying in the same direction. The average regression coefficient obtained from all selected SBP and HP sequences is the index of BRS (Seqgain). SBP and HR were recorded during 1 hour with a Finapres in 10 healthy male volunteers (NT), 23 to 32 year-old (SBP: 123 +/- 2 mmHg) and 10 recent and untreated hypertensive subjects (HT) (SBP: 152 +/- 6 mmHg). [table: see text] These results show that, in both groups, Zgain and Seqgain correlated with Csgain. No correlation was found between Zgain and Seqgain in healthy volunteers whereas the correlation was strong in hypertensives probably due to more heterogeneous SBP levels and BRS values in these subjects. This suggests that these methods are sensitive to different ways of response of the baroreflex.

A new non-invasive statistical method to assess the spontaneous cardiac baroreflex in humans

1. A new method was developed to evaluate cardiac baroreflex sensitivity. The association of a high systolic blood pressure with a low heart rate or the converse is considered to be under the influence of cardiac baroreflex activity. This method is based on the determination of the statistical dependence between systolic blood pressure and heart rate values obtained non-invasively by a Finapres device. Our computerized analysis selects the associations with the highest statistical dependence. A 'Z-coefficient' quantifies the strength of the statistical dependence. The slope of the linear regression, computed on these selected associations, is used to estimate baroreflex sensitivity. 2. The present study was carried out in 11 healthy resting male subjects. The results obtained by the 'Z-coefficient' method were compared with those obtained by cross-spectrum analysis, which has already been validated in humans. Furthermore, the reproducibility of both methods was checked after 1 week. 3. The results obtained by the two methods were significantly correlated (r = 0.78 for the first and r = 0.76 for the second experiment, P < 0.01). When repeated after 1 week, the average results were not significantly different. Considering individual results, test-retest correlation coefficients were higher with the Z-analysis (r = 0.79, P < 0.01) than with the cross-spectrum analysis (r = 0.61, P < 0.05). 4. In conclusion, as the Z-method gives results similar to but more reproducible than the cross-spectrum method, it might be a powerful and reliable tool to assess baroreflex sensitivity in humans.

Assessment of spontaneous baroreflex sensitivity in rats a new method using the concept of statistical dependence

A new method was developed to evaluate the cardiac baroreflex sensitivity (BRS) from spontaneous mean arterial pressure (MAP) and heart rate (HR) changes in conscious rats. It relies on the determination of the statistical dependence between MAP and HR values. In 13 control rats, 12 rats with a pharmacologically induced hypertension, and 7 rats with a chronic sinoaortic denervation (SAD), dependent (MAP, HR) couples related to the baroreflex activity were selected to determine the spontaneous BRS (Sp-BRS). In control and hypertensive rats, pharmacological BRS (Ph-BRS) was estimated using graded bolus intravenous doses of vasoactive drugs. Ph-BRS was significantly lower in hypertensive than in control rats. Sp-BRS was determined in 10 control and 10 hypertensive rats and was strongly correlated with Ph-BRS (r = 0.83, n = 20, P < 0.0001). Sp-BRS could be evaluated in six SAD rats and was profoundly decreased (-86%, P < 0.001) compared with control rats. In conclusion, this work validates the estimation of the cardiac BRS from spontaneous MAP and HR variations with use of (MAP, HR) couples of values that are statistically dependent.