Water and ion diffusion in partially-water saturated compacted kaolinite: Role played by vapor-phase diffusion in water mobility

Diffusion is the main transport process of water and solutes in clay-rich porous media owing to their very low permeability, so they are widely used as barriers against contaminant spreading. However, the prediction of contaminant mobility can be very complicated when these media are partially water-saturated. We conducted diffusion experiments for water (HTO and HDO) and ions (²²Na⁺ and ¹²⁵I^-) through partially water saturated compacted kaolinite, a weakly charged clay material, to quantify the distinct diffusive behavior of these species. The osmosis method was used to set kaolinite samples at 67, 86 and 100% saturation. The results showed that desaturation led to a sharp decrease in diffusive rates by factors of 6.5, 18 and 35 for HTO, ¹²⁵I^- and ²²Na⁺, respectively, from 100 to 67% of the degree of saturation. Thus, to interpret water diffusivities, we proposed a model taking into account the diffusion of water in both gas and liquid phases, using diffusion data obtained for ions, considered as inert species. This model was capable of properly predicting water diffusive flux, especially at a low degree of saturation (67% saturation), for which the assumption made for the occurrence of air phase continuity throughout the sample appears to be more relevant than at 86% saturation.

Abstract P5-12-05: Phenotypic discordance between primary and metastatic breast cancer (MBC) in a large scale real-life multicentre French cohort

Background: Therapeutic options at diagnosis for metastatic breast cancers (MBC) differ largely according to cancer phenotype (namely, hormone receptor (HR) and HER2 status). Reported discordance rates between primary tumor and metastasis vary widely in literature, with a median of 18% for estrogen receptor, 31% for progesterone receptor and 10% for HER2. The present study aimed to compare phenotypic profiles between primary and MBC in the real-life setting.

Patients (pts) and methods:

Epidemio-Strategy and Medical Economics (ESME)MBC data platform (NCT03275311) is a French national, multicenter, observational cohort using clinical trials' methodology for data capture, monitoring and quality controls. At the time of analysis, it comprised data of 16703 consecutive newly diagnosed MBC pts (1/01/08-31/12/14) treated in 18 French comprehensive cancer centres. The primary endpoint was the discordance rate of HR and HER2 status between primary tumor and MBC (biopsy of metastatic site done within 6 months of MBC diagnosis). Only patients with both histological reports available were considered. Potential factors associated with phenotype discordance were assessed in a multivariate logistic regression.

Results: 2933 out of 16703 (17.6%) had a biopsy in the first 6 months of metastatic disease. HR and/or HER2 status was available in 1677 pts. The discordance rate between primary and matched MBC was 14.2% (222/1566) for HR: loss of expression in 72.5%, gain in 27.5%. For HER2, the discordance rate was 7.8% (84/1076): 45.2% of losses and 54.8% of gains of expression. The primary HR+/HER2+ subgroup had the highest rate of changes: 53% (49/92) with either a loss of HR (43%), loss of HER2 (43%) or a loss of both (14%). 18% (33/181) of primary triple-negative breast cancer (TNBC) had a phenotypic change with a majority of HR gain (79%). In multivariate analysis, administration of adjuvant chemotherapy +/- targeted therapy was the sole independent predictor of HR status modification (OR: 1.73, 95%CI 1.27-2.36, p=0.001). The presence of a mixed histology was the only predictor of HER2 discordance (OR =2.57, 95%CI 1.19-5.55, p=0.016).

Patient characteristics Total population (n=16703)Pts with primary and MBC phenotype available (n=1677)Age at metastatic diagnosis Median (range)61 (19-99)60 (24-93)De novo MBC4507 (27.1%)221 (13.2%)Number of metastatic sites Median (range)1 (1-9)2 (1-7)MBC sites  Brain1200 (7.2%)138 (8.2%)Visceral7755 (46.4%)928 (55.3%)Non-visceral7748 (46.4%)611 (36.4%)Phenotypic profileN = 2933N=1677TNBC356 (18.5%)272 (19.3%)HR+/HER2-1251 (65.0%)917 (65.2%)HR-/HER2+150 (7.8%)105 (7.5%)HR+/HER2+168 (8.7%)112 (8%)Missing1008271Metastatic site samplingN=2933N=1677Bone692 (24.2%)419 (25.5%)Liver514 (18.0%)355 (21.6%)Skin379 (13.3%)203 (12.4%)Node306 (10.7%)169 (10.3%)Lung258 (9.0%)168 (10.2%)Pleura283 (9.9%)121 (7.4%)CNS/CSF*132 (4.6%)42 (2.6%)Other or multiple296 (10.3%)165 (10.0%)Missing7335* CNS= central nervous system, CSF=cerebro-spinal fluid

Conclusion: Biopsy and phenotype re-evaluation of MBC early in the disease course has a confirmed potential significant therapeutic impact in this large scale real life setting and should be proposed as often as possible.

Citation Format: Lefevre S, Lusque A, Joyon N, Arnould L, Penault-Llorca F, MacGrogan G, Treilleux I, Vincent-Salomon A, Haudebourg J, Maran-Gonzalez A, Charafe-Jauffret E, Courtinard C, Franchet C, Verriele V, Brain E, Tas P, Delaloge S, Filleron T, LaCroix-Triki M. Phenotypic discordance between primary and metastatic breast cancer (MBC) in a large scale real-life multicentre French cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-05.

Increased temperature tolerance of the air-breathing Asian swamp eel Monopterus albus after high-temperature acclimation is not explained by improved cardiorespiratory performance

This study investigated the hypothesis that in the Asian swamp eel Monopterus albus, an air-breathing fish from south-east Asia that uses the buccopharyngeal cavity for oxygen uptake, the upper critical temperature (TU) is increased by acclimation to higher temperature, and that the increased TU is associated with improved cardiovascular and respiratory function. Monopterus albus were therefore acclimated to 27° C (current average) and 32° C (current maximum temperature as well as projected average within 100-200 years), and both the effect of acclimation and acute temperature increments on cardiovascular and respiratory functions were investigated. Two weeks of heat acclimation increased upper tolerated temperature (TU ) by 2° C from 36·9 ± 0·1° C to 38·9 ± 0·1° C (mean ± s.e.). Oxygen uptake (M˙O2) increased with acclimation temperature, accommodated by increases in both aerial and aquatic respiration. Overall, M˙O2 from air (M˙O2a ) was predominant, representing 85% in 27° C acclimated fish and 80% in 32° C acclimated fish. M˙O2 increased with acute increments in temperature and this increase was entirely accommodated by an increase in air-breathing frequency and M˙O2a . Monopterus albus failed to upregulate stroke volume; rather, cardiac output was maintained through increased heart rate with rising temperature. Overall, acclimation of M. albus to 32° C did not improve its cardiovascular and respiratory performance at higher temperatures, and cardiovascular adaptations, therefore, do not appear to contribute to the observed increase in TU.

Measuring oxygen uptake in fishes with bimodal respiration

Respirometry is a robust method for measurement of oxygen uptake as a proxy for metabolic rate in fishes, and how species with bimodal respiration might meet their demands from water v. air has interested researchers for over a century. The challenges of measuring oxygen uptake from both water and air, preferably simultaneously, have been addressed in a variety of ways, which are briefly reviewed. These methods are not well-suited for the long-term measurements necessary to be certain of obtaining undisturbed patterns of respiratory partitioning, for example, to estimate traits such as standard metabolic rate. Such measurements require automated intermittent-closed respirometry that, for bimodal fishes, has only recently been developed. This paper describes two approaches in enough detail to be replicated by the interested researcher. These methods are for static respirometry. Measuring oxygen uptake by bimodal fishes during exercise poses specific challenges, which are described to aid the reader in designing experiments. The respiratory physiology and behaviour of air-breathing fishes is very complex and can easily be influenced by experimental conditions, and some general considerations are listed to facilitate the design of experiments. Air breathing is believed to have evolved in response to aquatic hypoxia and, probably, associated hypercapnia. The review ends by considering what realistic hypercapnia is, how hypercapnic tropical waters can become and how this might influence bimodal animals' gas exchange.

Air-breathing fishes in aquaculture. What can we learn from physiology?

During the past decade, the culture of air-breathing fish species has increased dramatically and is now a significant global source of protein for human consumption. This development has generated a need for specific information on how to maximize growth and minimize the environmental effect of culture systems. Here, the existing data on metabolism in air-breathing fishes are reviewed, with the aim of shedding new light on the oxygen requirements of air-breathing fishes in aquaculture, reaching the conclusion that aquatic oxygenation is much more important than previously assumed. In addition, the possible effects on growth of the recurrent exposure to deep hypoxia and associated elevated concentrations of carbon dioxide, ammonia and nitrite, that occurs in the culture ponds used for air-breathing fishes, are discussed. Where data on air-breathing fishes are simply lacking, data for a few water-breathing species will be reviewed, to put the physiological effects into a growth perspective. It is argued that an understanding of air-breathing fishes' respiratory physiology, including metabolic rate, partitioning of oxygen uptake from air and water in facultative air breathers, the critical oxygen tension, can provide important input for the optimization of culture practices. Given the growing importance of air breathers in aquaculture production, there is an urgent need for further data on these issues.

Swimming in air-breathing fishes

Fishes with bimodal respiration differ in the extent of their reliance on air breathing to support aerobic metabolism, which is reflected in their lifestyles and ecologies. Many freshwater species undertake seasonal and reproductive migrations that presumably involve sustained aerobic exercise. In the six species studied to date, aerobic exercise in swim flumes stimulated air-breathing behaviour, and there is evidence that surfacing frequency and oxygen uptake from air show an exponential increase with increasing swimming speed. In some species, this was associated with an increase in the proportion of aerobic metabolism met by aerial respiration, while in others the proportion remained relatively constant. The ecological significance of anaerobic swimming activities, such as sprinting and fast-start manoeuvres during predator-prey interactions, has been little studied in air-breathing fishes. Some species practise air breathing during recovery itself, while others prefer to increase aquatic respiration, possibly to promote branchial ion exchange to restore acid-base balance, and to remain quiescent and avoid being visible to predators. Overall, the diversity of air-breathing fishes is reflected in their swimming physiology as well, and further research is needed to increase the understanding of the differences and the mechanisms through which air breathing is controlled and used during exercise.

Juvenile idiopathic arthritis and exposure to fine particulate air pollution

OBJECTIVES

Inhalation of fine particulate matter, including particles with an aerodynamic diameter less than or equal to a 2.5-microm cut point (PM2.5), has been associated with systemic inflammation and the clinical presentation of various cardiopulmonary heath events. The urban area along Utah's Wasatch Mountains has high PM2.5 concentrations during periods of stagnant air conditions. Short-term inhalation exposures may trigger inflammatory events presenting as symptom onset in new patients with juvenile idiopathic arthritis (JIA). This study evaluated potential associations between JIA symptom onset and temporal changes in regional air pollution measured by stagnant air conditions and PM2.5 concentrations.

METHODS

A case-crossover design was used to analyze associations of regional ambient PM2.5 concentrations with onset date of 338 JIA cases living on Utah's Wasatch Front. Patients were drawn from the Intermountain States Database of Childhood Rheumatic Diseases (1993-2006). Time trends, seasonality, month, and weekday were controlled for by matching. Selected exposure windows of PM2.5 and stagnant air days were used in the model to determine the effect of short term cumulative exposure on JIA symptom onset.

RESULTS

Increased concentrations of PM2.5 and stagnant air conditions in the preceding 14 days were associated with significantly elevated risk of JIA onset in preschool aged children (RR=1.60, 95% CI 1.00-2.54) but not older children. Elevated risk was larger in males and in systemic onset JIA.

CONCLUSION

Exposure to stagnant polluted air may be an environmental risk factor for JIA in young children, potentially triggered by pollution-induced pulmonary mediated inflammation.

Infections néonatales à Candida

Candida infections in newborns are classified, as bacterial ones, in early onset or maternofoetal infections and late onset diseases, primitive and nosocomial. Candida infections are responsible of less than 1% of early onset sepsis. Their diagnosis is facilitated by suggestive cutaneous lesions which can be associated or not with systemic infection. Candida nosocomial infections are the most frequent, 7% in premature infants < 1500 g; they are associated with a central venous catheter or with cutaneous infection in extremely low birth weight infants. C. albicans is the predominant species in maternofoetal infections, contrary to nosocomial ones where C. parapsilosis is predominant, 60%. Both species are sensitive to fluconazole. Amphotericin B and its lipidic derivative Ambisome is the reference drug. Because of its lower toxicity and simplicity of administration, fluconazole is preferable for sensitive species. Its prophylactic use in colonized premature infants has been recently proposed.

A suicide-substrate mechanism for hydrolysis of beta-lactams by an anti-idiotypic catalytic antibody

The catalytic mechanism of an anti-idiotypic antibody, 9G4H9, displaying a beta-lactamase activity was investigated. Kinetics experiments suggest that some penicillinic derivatives behave both as substrates and inactivators. Biochemical and immunological experiments strongly indicate that ampicillin may be regarded as a suicide substrate for hydrolysis by 9G4H9. The anti-idiotypic network appears as a way to create enzyme mimics with modified catalytic activities.