Factors Influencing Objective and Subjective Prospective Memory Measures in Traumatic Brain Injury.

OBJECTIVE: To accurately assess prospective memory (PM) functioning in patients who sustained a traumatic brain injury (TBI), it is important to use both subjective (questionnaires) and objective (tests) measures. However, which factors have the most significant effect on each PM measure remains unknown. This observational study aims to verify whether TBI severity or psychological status has the most influence on patients' objective and subjective PM measures. METHOD: Fifteen healthy control (HC) participants (n = 15), 19 patients with a mild TBI (n = 19) and 30 patients with a moderate-to-severe TBI (n = 30) were recruited during the post-acute phase. For almost every participant, a relative was also recruited (n = 62). The Test écologique de mémoire prospective (TEMP), an objective computerized PM measure consisting of naturalistic stimuli, was administered to all participants along with anxiety (BAI) and depression inventories (BDI). Participants and their relatives also completed a questionnaire, the comprehensive assessment of PM (CAPM), a subjective PM measure assessing everyday failures. RESULTS: Results on the objective PM measure were predicted by TBI severity, while psychological symptoms (BAI and BDI) predicted scores on the subjective PM measure. In addition, relatives in the moderate-to-severe TBI group reported more PM failures on the subjective measure and their perception was significantly correlated with results on the objective PM measure, which was not the case for the other two groups of relatives. CONCLUSIONS: Objective PM measures are related to TBI severity and appear more robust against the influence of psychological factors than subjective PM measures.

Prospective memory assessment in acute mild traumatic brain injury.

Objective: Prospective memory (PM) is the ability to remember to perform an intention at the appropriate time in the future. It is of primary importance for daily living, and its disruption may impact functional autonomy. To date, few studies have examined PM during the acute phase of mild traumatic brain injury (mTBI), despite the high prevalence of this neurological condition and its potential impact on cognition. Method: Twenty mTBI patients (time since injury ranged from 45 to 73 days) and 15 healthy control participants performed the Ecological Test of Prospective Memory (TEMP), a simulated errand task in which participants were required to execute 10 event-based (EB) and five time-based (TB) tasks. The TEMP separately evaluates PM phases as well as prospective and retrospective components in event- and time-based conditions. Participants also completed a neuropsychological test battery. Correlations were performed between cognitive composite scores and the TEMP. Results: mTBI patients experienced difficulty in learning the content of intentions, retrieving these intentions in the time-based condition (prospective component) and recalling the associated actions in the event- and time-based conditions (retrospective component). Retrospective memory composite score was correlated with the learning and retention phases of the TEMP, whereas attention/working memory and executive composite scores were correlated with the time-based condition and performance on the ongoing task. Conclusion: These results suggest the presence of global PM impairment during the acute phase of mTBI, as well as impairment of retrospective memory, attention/working memory, and executive functions, which are key components for PM performance.

In vivo screening of multiple bacterial strains identifies Lactobacillus rhamnosus Lb102 and Bifidobacterium animalis ssp. lactis Bf141 as probiotics that improve metabolic disorders in a mouse model of obesity.

Given the growing evidence that gut dysfunction, including changes in gut microbiota composition, plays a critical role in the development of inflammation and metabolic diseases, the identification of novel probiotic bacteria with immunometabolic properties has recently attracted more attention. Herein, bacterial strains were first isolated from dairy products and human feces and then screened in vitro for their immunomodulatory activity. Five selected strains were further analyzed in vivo, using a mouse model of diet-induced obesity. C57BL/6 mice were fed a high-fat high-sucrose diet, in combination with 1 of 3 Lactobacillus strains (Lb38, L. plantarum; L79, L. paracasei/casei; Lb102, L. rhamnosus) or Bifidobacterium strains (Bf26, Bf141, 2 different strains of B. animalis ssp. lactis species) administered for 8 wk at 109 colony-forming units/d. Whereas 3 strains showed only modest (Lb38, Bf26) or no (L79) effects, Lb102 and Bf141 reduced diet-induced obesity, visceral fat accretion, and inflammation, concomitant with improvement of glucose tolerance and insulin sensitivity. Further analysis revealed that Lb102 and Bf141 enhanced intestinal integrity markers in association with selective changes in gut microbiota composition. We have thus identified 2 new potential probiotic bacterial strains with immunometabolic properties to alleviate obesity development and associated metabolic disturbances.-Le Barz, M., Daniel, N., Varin, T. V., Naimi, S., Demers-Mathieu, V., Pilon, G., Audy, J., Laurin, E., Roy, D., Urdaci, M. C., St-Gelais, D., Fliss, I, Marette, A. In vivo screening of multiple bacterial strains identifies Lactobacillus rhamnosus Lb102 and Bifidobacterium animalis ssp. lactis Bf141 as probiotics that improve metabolic disorders in a mouse model of obesity.

Multistrain probiotic modulation of intestinal epithelial cells' immune response to a double-stranded RNA ligand, poly(i·c).

A commercially available product containing three probiotic bacterial strains (Lactobacillus helveticus R0052, Bifidobacterium longum subsp. infantis R0033, and Bifidobacterium bifidum R0071) was previously shown in animal trials to modulate both TH1 and TH2 immune responses. Clinical studies on this combination of bacteria have also shown positive health effects against seasonal winter diseases and rotavirus infection. The goal of this study was to use a well-established in vitro intestinal epithelial (HT-29) cell model that has been shown to constitutively express double-stranded RNA (dsRNA) sensors (Toll-like receptor 3 [TLR3], retinoic acid-inducible gene I, melanoma differentiation-associated gene 5, and dsRNA-activated protein kinase). By using the HT-29 cell model, we wanted to evaluate whether or not this combination of three bacteria had the capacity to immune modulate the host cell response to a dsRNA ligand, poly(I·C). Using a custom-designed, two-color expression microarray targeting genes of the human immune system, we investigated the response of HT-29 cells challenged with poly(I·C) both in the presence and in the absence of the three probiotic bacteria. We observed that the combination of the three bacteria had a major impact on attenuating the expression of genes connected to proinflammatory TH1 and antiviral innate immune responses compared to that obtained by the poly(I·C)-only challenge. Major pathways through which the multistrain combination may be eliciting its immune-modulatory effect include the TLR3 domain-containing adapter-inducing beta interferon (TRIF), mitogen-activated protein kinase, and NF-κB signaling pathways. Such a model may be useful for selecting potential biomarkers for the design of future clinical trials.

Ecological prospective memory assessment in patients with traumatic brain injury.

PRIMARY OBJECTIVE: Prospective memory (PM) impairments are often observed after traumatic brain injury (TBI). Although PM is crucial for daily functioning, few sensitive, valid and ecological clinical tests are available. To address these concerns, the authors developed a PM task, the TEMP, using naturalistic stimuli, in which each PM phase and component is evaluated independently in time- and event-based conditions. MAIN OUTCOMES AND RESULTS: The results show that moderate and severe TBI patients (n = 30), evaluated after spontaneous neurological recovery, experienced problems in learning the delayed intentions content and retrieving these intentions in the right context (prospective component), especially in the time-based condition. They also recalled fewer associated actions (retrospective component), but only in the time-based condition. Correlations revealed that the retrospective component was mainly supported by episodic retrospective memory processes, while the prospective component was supported by episodic retrospective memory processes, along with attentional and executive functions. Moreover, there was a significant correlation between performance on the TEMP and results on a questionnaire assessing PM functioning in daily living completed by participants' relatives. CONCLUSIONS: The TEMP therefore appears to be a sensitive tool for assessing PM problems that combines internal and ecological validity.

Sugar source modulates exopolysaccharide biosynthesis in Bifidobacterium longum subsp. longum CRC 002.

The effect of four sugars (glucose, galactose, lactose and fructose) on exopolysaccharide (EPS) production by Bifidobacterium longum subsp. longum CRC 002 was evaluated. More EPS was produced when CRC 002 was grown on lactose in the absence of pH control, with a production of 1080+/-120 mg EPS l(-1) (P<0.01) after 24 h of incubation. For fructose, galactose and glucose, EPS production was similar, at 512+/-63, 564+/-165 and 616+/-93 mg EPS l(-1), respectively. The proposed repeating unit composition of the EPS is 2 galactose to 3 glucose. The effect of sugar and fermentation time on expression of genes involved in sugar nucleotide production ( galK, galE1, galE2, galT1, galT2, galU, rmlA, rmlB1 and rmlCD) and the priming glycosyltransferase ( wblE) was quantified using real-time reverse transcription PCR. A significantly higher transcription level of wblE (9.29-fold) and the genes involved in the Leloir pathway (galK, 4.10-fold; galT1, 2.78-fold; and galE2, 4.95-fold) during exponential growth was associated with enhanced EPS production on lactose compared to glucose. However, galU expression, linking glucose metabolism with the Leloir pathway, was not correlated with EPS production on different sugars. Genes coding for dTDP-rhamnose biosynthesis were also differentially expressed depending on sugar source and growth phase, although rhamnose was not present in the composition of the EPS. This precursor may be used in cell wall polysaccharide biosynthesis. These results contribute to understanding the changes in gene expression when different sugar substrates are catabolized by B. longum subsp. longum CRC 002.