A refined molecular taxonomy of breast cancer

The current histoclinical breast cancer classification is simple but imprecise. Several molecular classifications of breast cancers based on expression profiling have been proposed as alternatives. However, their reliability and clinical utility have been repeatedly questioned, notably because most of them were derived from relatively small initial patient populations. We analyzed the transcriptomes of 537 breast tumors using three unsupervised classification methods. A core subset of 355 tumors was assigned to six clusters by all three methods. These six subgroups overlapped with previously defined molecular classes of breast cancer, but also showed important differences, notably the absence of an ERBB2 subgroup and the division of the large luminal ER+ group into four subgroups, two of them being highly proliferative. Of the six subgroups, four were ER+/PR+/AR+, one was ER−/PR−/AR+ and one was triple negative (AR−/ER−/PR−). ERBB2-amplified tumors were split between the ER−/PR−/AR+ subgroup and the highly proliferative ER+ LumC subgroup. Importantly, each of these six molecular subgroups showed specific copy-number alterations. Gene expression changes were correlated to specific signaling pathways. Each of these six subgroups showed very significant differences in tumor grade, metastatic sites, relapse-free survival or response to chemotherapy. All these findings were validated on large external datasets including more than 3000 tumors. Our data thus indicate that these six molecular subgroups represent well-defined clinico-biological entities of breast cancer. Their identification should facilitate the detection of novel prognostic factors or therapeutical targets in breast cancer.

Effect of continuous positive airway pressure treatment on the subsequent EEG spectral power and sleepiness over sustained wakefulness in patients with obstructive sleep apnea-hypopnea syndrome

OBJECTIVE

To determine whether sleepiness and its evolution over sustained wakefulness could be reversed by nasal continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

Twelve OSAHS patients underwent three 32-h sessions of study: one before CPAP therapy (T0), the second (T3) and the third (T6), respectively, after 3 and 6 months of therapy. Each session included one night of sleep followed by 24 h of sustained wakefulness, during which EEG recordings and subjective ratings were performed every hour.

RESULTS

The waking EEG in treated OSAHS patients was partially improved after 3 months of CPAP and their subjective complaint of sleepiness was normalized after 6 months. Theta power (3.9-7.8 Hz) was decreased as well as its time course during the diurnal period but beta power (12.7-29.2 Hz) remained higher.

CONCLUSIONS

CPAP partially reverses waking EEG abnormalities in OSAHS patients with reduced theta activity after 3 months and removes the subjective complaint of sleepiness after 6 months. Nevertheless, the persistence of increased beta activity in treated patients suggests that efforts to stay awake remain strong after CPAP treatment.

SIGNIFICANCE

CPAP influences the EEG's time course over sustained wakefulness in a frequency-specific manner in OSAHS patients.

An experimental investigation of the effect of the amount of lubricant on tablet properties

BACKGROUND

Magnesium stearate (MgSt) is widely used as a lubricant in the production of tablets. However, the amount added to a formulation is often too high or it is poorly mixed, which can lead to the production of tablets whose properties are out of specifications.

METHOD

The objective of this work was to investigate by means of a new method based on gamma-ray flux measurement and to study the impact of the amount of MgSt on the mass, thickness, hardness, friability, and disintegration time of tablets containing a 50 : 50 wt.% microcrystalline cellulose and spray-dried lactose pre-blend. Other blends were lubricated with sodium lauryl sulfate (SLS) to compare the performance of the two lubricants in equal amounts.

RESULTS

It was observed that, contrary to SLS, a greater amount of MgSt increased the variability of the tablet mass. The tablet hardness decreased with an increasing amount of MgSt, whereas it remained relatively unaffected by the presence of SLS. No solid conclusion could be drawn concerning the relationship between the lubricant concentration and the tablet friability.

CONCLUSION

An amount of 0.25 wt.% MgSt and 0.75 wt.% SLS were found to be sufficient amounts of lubricants to obtain a proper compression.

Shear induced drainage in foamy yield-stress fluids

Shear induced drainage of a foamy yield-stress fluid is investigated using MRI techniques. Whereas the yield stress of the interstitial fluid stabilizes the system at rest, a fast drainage is observed when a horizontal shear is imposed. It is shown that the sheared interstitial material behaves as a viscous fluid in the direction of gravity, the effective viscosity of which is controlled by shear in transient foam films between bubbles. Results provided for several bubble sizes are not captured by the R2 scaling classically observed for foams. Furthermore, foam films are found to be responsible for the unexpected arrest of drainage, thus trapping irreversibly a significant amount of interstitial liquid.

Solid-liquid transition and rejuvenation similarities in complex flows of thixotropic materials studied by NMR and MRI

We study the flow of a typical thixotropic material subjected to very different deformation histories (squeeze, shear, and extrusion) with either local (proton NMR and magnetic resonance imaging) or macroscopic measurements after different times of rest. Specifically, we measure the velocity fields and the spin-spin NMR relaxation of the material after different flow histories. The relaxation data exhibits a long relaxing component revealing information about the reversible microstructural evolution of the sample during aging-rejuvenation cycles. We show that for each deformation process, the evolution of the viscosity during the solid-liquid transition is similar by a factor related to the initial state of the material. Moreover, results examining the impact of the rate at which the deformation is imposed suggest that the state of the material during this transition may be described by a single parameter reflecting the average size and deformation of the material's flocs. These results also show that localization of flow occurs as a result of a progressive differential evolution of the material in different regions of the flow, and thus are determined by the boundary conditions of the flow.

Newly characterised ex vivo colospheres as a three-dimensional colon cancer cell model of tumour aggressiveness

Background:

New models continue to be required to improve our understanding of colorectal cancer progression. To this aim, we characterised in this study a three-dimensional multicellular tumour model that we named colospheres, directly obtained from mechanically dissociated colonic primary tumours and correlated with metastatic potential.

Methods:

Colorectal primary tumours (n=203) and 120 paired non-tumoral colon mucosa were mechanically disaggregated into small fragments for short-term cultures. Features of tumours producing colospheres were analysed. Further characterisation was performed using colospheres, generated from a human colon cancer xenograft, and spheroids, formed on agarose by the paired cancer cell lines.

Results:

Colospheres, exclusively formed by viable cancer cells, were obtained in only 1 day from 98 tumours (47%). Inversely, non-tumoral colonic mucosa never generated colospheres. Colosphere-forming capacity was statistically significantly associated with tumour aggressiveness, according to AJCC stage analysis. Despite a close morphology, colospheres displayed higher invasivity than did spheroids. Spheroids and colospheres migrated into Matrigel but matrix metalloproteinase (MMP)-2 and MMP-9 activity was detected only in colospheres. Mouse subrenal capsule assay revealed the unique tumorigenic and metastatic phenotype of colospheres. Moreover, colospheres and parental xenograft reproduced similar CD44 and CD133 expressions in which CD44⁺ cells represented a minority subset of the CD133⁺ population.

Conclusion:

The present colospheres provide an ex vivo three-dimensional model, potentially useful for studying metastatic process.

Impact of high-fat /low-carbohydrate, high-, low-glycaemic index or low-caloric meals on glucose regulation during aerobic exercise in Type 2 diabetes

AIMS

A decrement in blood glucose (BG) may be observed in patients with Type 2 diabetes (T2DM) when exercise is performed after a meal, in contrast to fasting. We determined the impact of different pre-exercise meal macronutrient compositions with modulation of the glycaemic index (GI) on glucose regulation during exercise in patients with T2DM.

METHODS

Using a randomized, single-blind crossover design, 10 sedentary men performed five exercise sessions, once after an overnight fast, and also after each of four test meals, consisting of a high-fat/low-carbohydrate meal, a high-GI meal, a low-GI meal, and a low-calorie meal.

RESULTS

Pre-exercise BG and insulin levels were comparable for all four meals. Exercise decreased BG and insulin levels during all meal conditions (all P < 0.001) compared with the fasting state in which BG levels did not change. The magnitude of BG and insulin decrements was similar after consuming the low-calorie, the high-GI and the high-fat/low-carbohydrate meals, whereas the low-GI meal induced the lowest BG fall. Adrenaline response was higher after consumption of the high-, the low-GI and the low-caloric meals compared with the high-fat/low-carbohydrate meal and with the fasting state (P < 0.05).

CONCLUSIONS

This study underlines the beneficial effect of low-GI foods and the differential impact of pre-exercise meal macronutrient composition on BG decrease. This may protect against exercise-induced hypoglycaemia, and reiterates the safety of exercising while fasting in T2DM patients.

A characterization of grapevine trunk diseases in France from data generated by the National Grapevine Wood Diseases Survey

Farmers' field survey data sets represent extremely valuable information, often having a heterogeneous data format. A large number of methods are available to process this kind of information, which may be combined to address successive, connected hypotheses, with definite objectives. The National Grapevine Trunk Diseases Survey was established in France in order to monitor and analyze the importance and progress of several grapevine diseases, in particular Eutypa dieback and Esca decline. Here we report a first series of analyses pertaining to the years 2003 to 2005 to characterize the incidences of the two diseases, as well as grapevine mortality, in relation to grapevine age, crop management, cultivars, and growing regions. Information representing 256 individual vineyards indicated mean incidences of 2.23 and 3.25% for Eutypa dieback and Esca decline, respectively. A combination of approaches (hierarchical cluster analysis, multiple correspondence analyses, and binomial logistic regressions) indicated distinct patterns of variation in the incidences of the two diseases according to crop management practices; limited linkage of specific crop management practices with diseases, especially Esca decline; a shared contribution of both diseases to mortality; and a weak linkage of the (now banned) arsenite-based pesticides with reduced Esca decline symptoms, but no such association with grapevine mortality. Differences and complementarities of the analytical approaches are discussed, as well as the implications of these analyses on grapevine health.