Are energy drinks unique mixers in terms of their effects on alcohol consumption and negative alcohol-related consequences?

INTRODUCTION: Previous research has suggested that consuming alcohol mixed with energy drinks (AMED) increases overall alcohol consumption. However, there is limited research examining whether energy drinks are unique in their effects when mixed with alcohol, when compared with alcohol mixed with other caffeinated mixers (AOCM). Therefore, the aim of this survey was to investigate alcohol consumption on AMED occasions, to that on other occasions when the same individuals consumed AOCM or alcohol only (AO). METHODS: A UK-wide online student survey collected data on the frequency of alcohol consumption and quantity consumed, as well as the number of negative alcohol-related consequences reported on AO, AMED and AOCM occasions (N=250). RESULTS: Within-subjects analysis revealed that there were no significant differences in the number of alcoholic drinks consumed on a standard and a heavy drinking session between AMED and AOCM drinking occasions. However, the number of standard mixers typically consumed was significantly lower on AMED occasions compared with AOCM occasions. In addition, when consuming AMED, students reported significantly fewer days consuming 5 or more alcohol drinks, fewer days mixing drinks, and fewer days being drunk, compared with when consuming AOCM. There were no significant differences in the number of reported negative alcohol-related consequences on AMED occasions to AOCM occasions. Of importance, alcohol consumption and negative alcohol-related consequences were significantly less on both AMED and AOCM occasions compared with AO occasions. CONCLUSION: The findings that heavy alcohol consumption occurs significantly less often on AMED occasions compared with AOCM occasions is in opposition to some earlier claims implying that greatest alcohol consumption occurs with AMED. The overall greatest alcohol consumption and associated negative consequences were clearly associated with AO occasions. Negative consequences for AMED and AOCM drinking occasions were similar, suggesting that energy drink was comparable with AOCM in this regard.

A UK student survey investigating the effects of consuming alcohol mixed with energy drinks on overall alcohol consumption and alcohol-related negative consequences.

Previous research reported positive associations between alcohol mixed with energy drink (AMED) consumption and overall alcohol consumption. However, results were largely based on between-subjects comparisons comparing AMED consumers with alcohol-only (AO) consumers, and therefore cannot sufficiently control for differences in personal characteristics between these groups. In order to determine whether AMED consumers drink more alcohol on occasions they consume AMED compared to those when they drink AO additional within-subjects comparisons are required. Therefore, this UK student survey assessed both alcohol consumption and alcohol-related negative consequences when consumed alone and when mixed with energy drinks, using a within-subject design. A total of 1873 students completed the survey, including 732 who consumed AMED. It was found that AMED consumers drank significantly less alcohol when they consumed AMED compared to when they drank AO (p < 0.001). In line with reduced alcohol consumption significantly fewer negative alcohol-related consequences were reported on AMED occasions compared to AO occasions (p < 0.001). These findings suggest that mixing alcohol with energy drinks does not increase total alcohol consumption or alcohol-related negative consequences.

Motives for mixing alcohol with energy drinks and other non-alcoholic beverages and its effects on overall alcohol consumption among UK students.

INTRODUCTION: A UK student survey examined the motivations for consuming energy drinks alone and mixed with alcohol, and aimed to determine whether the type of motive had a differential effect on overall alcohol consumption. METHODS: The online survey (N = 1873) assessed alcohol consumption and motivations for consumption when mixed with energy drinks (AMED) and mixed with other non-alcoholic beverages (AMOB) using a within-subject design. RESULTS: The most frequent neutral motives reported for AMED consumption included "I like the taste" (66.5%), and "to celebrate a special occasion" (35.2%). 52.6% of AMED consumers reported consuming AMED for at least one of five negative motives, primarily "to get drunk" (45.6%). Despite these negative motives those students reported consuming significantly less alcohol and fewer negative alcohol-related consequences on AMED occasions compared to alcohol-only (AO) occasions. Although the motives for consuming AMED and AMOB were comparable, more participants reported consuming AMED "to celebrate a special occasion", "to get drunk", because they "received the drink from someone else" or "because others drink it as well". However, significantly more students reported consuming AMOB than AMED because "It feels like I can drink more alcohol". Alcohol consumption was significantly less on AMED occasions compared to AMOB occasions, and both occasions significantly less than AO occasions. CONCLUSION: The majority of reasons for consuming AMED relate to neutral motives. Although 52.6% of students reported one or more negative motives for AMED consumption (predominantly "to get drunk") this had no differential effect on total alcohol consumption. The differences in motives suggest AMED is consumed more to enjoy special occasions and as a group-bonding experience, however alcohol consumption is significantly lower on such occasions in comparison to when AMOB or AO are consumed.

Isolation of C15: a novel antibody generated by phage display against mesenchymal stem cell-enriched fractions of adult human marrow.

Adult bone marrow stroma contains a source of mesenchymal stem cells (MSC) that have the capacity to self-renew and differentiate into multiple stromal lineages. These rare cells can be visualised indirectly by the formation of heterogeneous colonies, containing stem cells and their differentiated progeny in long-term culture. If MSC and their associated progenitor and precursor populations are to reach their full therapeutic potential, markers will be required to identify and characterize specific bone marrow stromal subsets. We sought to use phage display to generate antibodies against bone marrow mononuclear cells (BMMNC) enriched for colony forming cells. Initially, we identified our target cell population by comparing the colony forming efficiency (CFE) of CD49a-positive, STRO-1-positive and CD45-negative BMMNC subpopulations with unseparated BMMNC. Selection with anti-CD49a gave the greatest enrichment (19-fold) of colony forming cells and in light of these findings, we generated phage antibodies against CD49a-positive BMMNC by simultaneous positive/negative selection. A dominant clone (C15), generated after 3 rounds of selection, has been isolated and sequenced, then characterized for cell and tissue specificity. Sequence analysis showed that the V(H) and V(L) gene segments of C15 aligned most closely to the VH26/DP-47 and IGLV3S1/DPL16 germline V segments found in the synthetic repertoire. C15 bound to 4% of freshly isolated BMMNC and localized to osteoblastic cells and proximal marrow cells in areas of active bone formation in sections of osteophyte. C15 binding was upregulated in cultured bone marrow stromal cells (BMSC) and was also detected on bone-derived cell lines. This report demonstrates that phage display is a powerful tool for the isolation of antibodies against rare cell populations, and provides a platform for the future application of this technology in the search for antigens on MSC and other rare cell populations.

A comparison of colorimetric and DNA quantification assays for the assessment of meniscal fibrochondrocyte proliferation in microcarrier culture.

We have developed and refined a rapid, reliable method for the evaluation of attachment and proliferation of ovine meniscal chondrocytes in microcarrier culture. Assays measuring both mitochondrial activity, using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and MTS [3-(4,5-dimethylthiazol-2-yl)5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium], and DNA synthesis with a PicoGreen assay were compared. The MTT assay was the most sensitive at lower cell concentrations and enabled accurate assessment of cell proliferation over 14 day culture.

STRO-1, HOP-26 (CD63), CD49a and SB-10 (CD166) as markers of primitive human marrow stromal cells and their more differentiated progeny: a comparative investigation in vitro.

There is widespread interest in the use of bone marrow stromal cells (BMSC) for tissue reconstruction and repair and for gene therapy. BMSC represent the differentiated progeny of CFU-F, which however comprise a developmentally heterogeneous population as is reflected in the cellular heterogeneity of the cell populations to which they give rise. We have compared the efficacy of monoclonal antibodies recognising a series of stromal antigens, viz. STRO-1, HOP-26, CD49a and SB-10/CD166, as tools for the enrichment of CFU-F prior to culture and as developmental markers for culture-expanded BMSC. In freshly isolated bone marrow mononuclear cells (BMMNC), the proportion of antigen-positive cells was 27%, 46%, 5% and 19% for STRO-1, HOP-26, CD49a and CD166, respectively. All CD49a(+) cells co-expressed STRO-1. The degree of CFU-F enrichment obtained with anti-CD49a (approximately 18-fold) by a one-pass immunoselection strategy was significantly greater than that of all other antibodies tested. BMSC expressed higher levels of all antigens investigated (except for HOP-26) compared with BMMNC. Expression of STRO-1 and CD49a remained restricted to a subset of BMSC, whereas all BMSC were SB-10/CD166 positive. Treatment with dexamethasone (10 nM), which promotes the differentiation and further maturation of cells of the osteogenic lineage in this cell culture system, increased the expression of CD49a and HOP-26. The CD49a(+) and HOP-26(+) fractions of BMSC were further subdivided by dual-labelling with anti-STRO-1 and B4-78 (an antibody recognising the B/L/K isoform of the enzyme alkaline phosphatase), respectively. By using a variety of criteria, the HOP-26 antigen was identified as CD63, a member of the tetraspanin family of proteins thought to modulate integrin compartmentalisation and signalling.

TGFbeta1 limits the expansion of the osteoprogenitor fraction in cultures of human bone marrow stromal cells.

Currently, there is considerable interest in the possibility of using cultured human bone marrow stromal cells (BMSCs) for skeletal tissue engineering. However, the factors that regulate their ex vivo expansion and promote their osteogenic maturation remain poorly defined. Using BMSCs obtained from a large cohort of adult donors, the effects of transforming growth factor (TGF)beta1 on these processes have been determined. BMSCs were found to express TGFbeta receptors (TbetaRs) I, II, III (betaglycan) and CD105/endoglin. The expression of TbetaRs I and II, but not TbetaR III or endoglin, was linked to the cells' state of maturation. Treatment with TGFbeta increased the colony-forming efficiency (CFE) of marrow cell suspensions but reduced the median diameter of the colonies that formed and the number of cells harvested at the end of primary culture. Treatment with TGFbeta also resulted in a significant downregulation in the expression of the developmental markers alkaline phosphatase (AP) and STRO-1. The reduction in AP was due to a decrease in the absolute number of cells expressing this enzyme and in the level (sites/cell) at which it was expressed. Overall, the changes in the expression of STRO-1 and AP are consistent with TGFbeta acting to decrease the size of the osteoprogenitor fraction, and hence the potential clinical utility of the cultured cell population.