Association of salivary alpha-amylase and salivary flow rate with working memory functioning in healthy children.

The aim of this study was to examine the association between auditory and visual working memory (WM) performance and salivary alpha-amylase (sAA) and salivary flow rate (SFR) in a sample of 63 children (38 boys). WM was assessed by means of WISC-V subtests: four auditory subtests (Digit Span and Letter-Number Sequencing) and one visual subtest (Picture Span). SAA activity, output, and SFR were measured at baseline (10 min prior to testing), one minute prior to testing, one minute after the end of the auditory WM subtests and one minute after the end of the visual WM subtest. Our statistical analyses showed an association among SAA activity, output and SFR levels and the number of recalled digits in the last attempt score in Letter-Number Sequencing subtest. Specifically, our results showed that working performance in this task was associated with a concurrent decrease in SFR (r(63) = -0.423, p < .05). This salivary measure was the best predictor of this specific index of working memory performance (ß = -0.423, p < .05). These results show that the changes in SFR, which represents changes in parasympathetic tone, could be employed in future studies as a noninvasive marker of working memory performance in child studies.

Impact of salivary enzyme activity on the oral perception of starch containing foods.

It has long been held that product developers should not rely solely on instrumental measures of texture. This study examined the widely accepted effects of salivary α amylase on mouth thinning during oral processing. To understand this phenomenon, 13 descriptive panelists were trained to manipulate starch thickened semisolid foods and note when changes in the perceived thickness occurred. The panelists were subsequently grouped based on their reports of how quickly these foods broke down in their oral cavity. The accepted effect of salivary α amylase was then analyzed and found to be consistent across the starch thickened foods examined but different among the panelists. Thus it became clear that starch containing foods with long residence times in the mouth can be perceived differently among people based on their amylase activity, making descriptive profiling difficult to calibrate. This study suggests that classic sensory techniques could also have limitations when considering the oral processing of starchy foods, especially those with long residence times in the oral cavity. Panelists' individual salivary amylase activity was not measured in this study. PRACTICAL APPLICATIONS: Food texture is an important sensory attribute that affects consumers' acceptance of products. Semisolid foods such as puddings and yogurts are expected to thin as the food is manipulated in the mouth. By the same token, starch systems in chewy candies can also be impacted over long periods of mastication. Understanding the impact of salivary amylase on how quickly these foods breakdown is important to developing foods that will be acceptable to consumers. Developers with an understanding of the effects salivary amylase has on various starches can lead them to design products that perform more consistently across individuals with different activity levels of salivary α amylase.

CREB-binding protein (CBP) regulates ß-adrenoceptor (ß-AR)-mediated apoptosis.

Catecholamines regulate the ß-adrenoceptor/cyclic AMP-regulated protein kinase A (cAMP/PKA) pathway. Deregulation of this pathway can cause apoptotic cell death and is implicated in a range of human diseases, such as neuronal loss during aging, cardiomyopathy and septic shock. The molecular mechanism of this process is, however, only poorly understood. Here we demonstrate that the ß-adrenoceptor/cAMP/PKA pathway triggers apoptosis through the transcriptional induction of the pro-apoptotic BH3-only Bcl-2 family member Bim in tissues such as the thymus and the heart. In these cell types, the catecholamine-mediated apoptosis is abrogated by loss of Bim. Induction of Bim is driven by the transcriptional co-activator CBP (CREB-binding protein) together with the proto-oncogene c-Myc. Association of CBP with c-Myc leads to altered histone acetylation and methylation pattern at the Bim promoter site. Our findings have implications for understanding pathophysiology associated with a deregulated neuroendocrine system and for developing novel therapeutic strategies for these diseases.

A mouse model of the most aggressive subgroup of human medulloblastoma.

Medulloblastomas that display a large cell/anaplastic morphology and overexpress the cellular c-MYC gene are highly aggressive and carry a very poor prognosis. This so-called MYC-subgroup differs in its histopathology, gene expression profile, and clinical behavior from other forms of medulloblastoma. We generated a mouse model of MYC-subgroup medulloblastoma by transducing Trp53-null cerebellar progenitor cells with Myc. The cardinal features of these mouse medulloblastomas closely mimic those of human MYC-subgroup tumors and significantly differ from mouse models of the Sonic-Hedgehog- and WNT-disease subgroups. This mouse model should significantly accelerate understanding and treatment of the most aggressive form of medulloblastoma and infers distinct roles for MYC and MYCN in tumorigenesis.