No abstract

Circadian rhythms are prevalent in most organisms. Even the smallest disturbances in the orchestration of circadian gene expression patterns among different tissues can result in functional asynchrony, at the organism level, and may to contribute to a wide range of physiologic disorders. It has been reported that as many as 5%–10% of transcribed genes in peripheral tissues follow a circadian expression pattern. We have conducted a comprehensive study of circadian gene expression on a large dataset representing three different peripheral tissues. The data have been produced in a large-scale microarray experiment covering replicate daily cycles in murine white and brown adipose tissues as well as in liver. We have applied three alternative algorithmic approaches to identify circadian oscillation in time series expression profiles. Analyses of our own data indicate that the expression of at least 7% to 21% of active genes in mouse liver, and in white and brown adipose tissues follow a daily oscillatory pattern. Indeed, analysis of data from other laboratories suggests that the percentage of genes with an oscillatory pattern may approach 50% in the liver. For the rest of the genes, oscillation appears to be obscured by stochastic noise. Our phase classification and computer simulation studies based on multiple datasets indicate no detectable boundary between oscillating and non-oscillating fractions of genes. We conclude that greater attention should be given to the potential influence of circadian mechanisms on any biological pathway related to metabolism and obesity.

Background Adipose-derived stromal/stem cells (ASC) capable of multipotential differentiation can be isolated with high yield from human subcutaneous lipoaspirates. This study reports our recent experience isolating and immunophenotypically characterizing ASCs from >60 human subjects of mean age 43.6 and mean body mass index of 27. Methods We examined the ASC yield per unit volume of lipoaspirate tissue, their surface antigen profile based on flow cytometry, their histochemical differentiation potential along the adipogenic and osteogenic pathways, and their expression of adipogenic mRNAs by transcriptomic microarray and RT-PCR. Results The population (n = 64) of predominantly Caucasian (84.3%) female (90.6%) donors had a mean age of 43.6 ± 11.1 years and a mean body mass index of 27.0 ± 3.8. A yield of 375 ± 142 × 103 ASC was obtained per ml of lipoaspirate within a 4.1 ± 0.7 day culture period (n = 62). The ASC population was uniformly CD29+ CD34+CD44loCD45loCD73+CD90+CD105+ and capable of undergoing both adipogenesis and osteogenesis in vitro based on Oil Red O and Alizarin Red staining, respectively. Adipogenic differentiation was associated with the significant induction of multiple mRNAs associated with lipid storage and synthesis based microarray analysis of n = 3 donors. During an adipogenic differentiation time course, representative mRNAs (adiponectin, C/EBPα, leptin, LPL) displayed increases of several orders of magnitude. Discussion These findings demonstrate the reproducibility of subcutaneous lipoaspirates as a consistent and abundant source of functional ASCs from donors across a spectrum of ages and BMIs. These results have relevance to regenerative medical applications exploiting autologous or allogeneic ASCs for soft and hard tissue engineering.

This very limited case series suggest there may be a role for therapeutic plasma exchange as a rescue therapy in severe shock and acute lung injury related to pH1N1 that has not responded to traditional therapy.

Percutaneous cannulation for extracorporeal membrane oxygenation by intensivists can be performed with a high rate of success and a low rate of complications when accompanied by imaging support.