Gene expression in human adipose-derived stem cells: comparison of 2D films, 3D electrospun meshes or co-cultured scaffolds with two-way paracrine effects.

Finding the appropriate cues to trigger the desired differentiation is a challenge in tissue engineering when stem cells are involved. In this regard, three-dimensional environments are often compared to cells' two-dimensional culture behaviour (plastic culture dish). Here, we compared the gene expression pattern of human adipose-derived stem cells (ASC) seeded in a three-dimensional (3D) electrospun mesh and on a two-dimensional (2D) film - both of exactly the same material. Additionally, we conducted experiments with a scaffold floating above a film to investigate two-way paracrine effects (co-system). Electrospun meshes (3D scaffolds) and films (2D), consisting either of pristine poly-lactic-co-glycolic acid (PLGA) or of PLGA-containing dispersed amorphous calcium phosphate nanoparticles (PLGA/aCaP), were seeded with ASCs and cultured either in Dulbecco Minimum Essential Medium (DMEM) or in osteogenic medium. After two weeks, minimum stem cell criteria markers as well as typical markers for osteogenesis, endothelial cell differentiation, adipogenesis and chondrogenesis were analysed by quantitative real-time PCR. Interestingly, mostly osteogenic genes of cells seeded on 3D meshes were upregulated compared to those on 2D films, while stem cell markers seemed to be only slightly affected. Runx2 and osteocalcin showed an especially strong upregulation under all conditions, while most other factors analysed for 2D/3D changes were highly dependent on the material composition, the culture medium and on paracrine signalling effects. The beneficial 3D environment for stem cells found in many studies has therefore not to be attributed to the third dimension alone and should carefully be compared to 2D films fabricated of the same material. Furthermore, paracrine interactions triggering differentiation are not negligible.

Study of the antinociceptive action of the ethanolic extract and the triterpene 24-hydroxytormentic acid isolated from the stem bark of Ocotea suaveolens.

We describe here the antinociceptive action of the crude extract (CE), the chemical isolation and characterisation and preliminary pharmacological analysis of 24-hydroxytormentic acid, isolated from the stem bark of Ocotea suaveolens (Lauraceae). The CE given by i.p. or p.o. routes, 30 min and 1 h prior, produced significant inhibition of abdominal constrictions caused by acetic acid and also inhibited both phases of formalin-induced licking in mice. The antinociception caused by the CE, given by i.p. and p.o. routes, lasted up to 4 and 2h, respectively. When assessed in the hot-plate test, the CE was inactive. Its antinociceptive action was not associated with non-specific effects such as muscle relaxation or sedation. The antinociception of CE was not influenced by naloxone, L-arginine or DL-p-chlorophenylalanine methyl ester, when assessed against the formalin assay. The triterpene 24-hydroxytormentic acid, given i.p. 30 min before testing, produced significant, dose-related and equipotent antinociceptive action against both phases of formalin-induced licking in mice. These results demonstrate, for the first time, the occurrence of the triterpene 24-hydroxytormentic acid in the stem bark of Ocotea suaveolens, and show that the CE and 24-hydroxytormentic acid exhibit marked antinociception against the neurogenic and the inflamamtory algesic responses induced by formalin in mice. The mechanism by which this compound and CE produces antinociception still remains unclear, but is unlikely to involve the activation of opioid, nitric oxide or serotonin systems or non-specific peripheral or central depressant actions.

Antibacterial activity and phytochemical analysis of Vochysia divergens (Vochysiaceae).

Vochysia divergens Pohl (Vochysiaceae) is a tree commonly found in wet soils of 'Pantanal' of Mato Grosso, Brazil, and used in folk medicine against infections and asthma. We have studied different extracts and some isolated compounds from this plant for antibacterial activity. From the extracts of the stem bark beta-sitosterol, betulinic acid and sericic acid were isolated. The minimal inhibitory concentration (MIC) for Staphylococcus aureus were: ethanolic extract (MIC = 1.5 mg/ml); ethyl acetate extract (MIC = 2.0 mg/ml); and sericic acid (MIC = 1.0 mg/ml). Escherichia coli was resistant until 5 mg/ml.

The effect of employment and welfare on family structure: explaining the time trend of female-headed families.

PIP: The author critically reviews various hypotheses that have been put forward in order to explain the rise in the number of female-headed single-parent families among both blacks and whites in the United States. Specifically, regression of time series data is used to examine the relative effects of welfare benefits, male and female employment rates, and changing social values.^ieng