A metabolomics approach to characterize raw, pasteurized, and ultra-high temperature milk using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and multivariate data analysis.

We developed a metabolomics workflow using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry to determine the effect of thermal treatment on milk composition and metabolites based on multivariate data analysis. We analyzed raw, pasteurized, and UHT milk samples. The samples were first centrifuged to remove the fat layer and mixed with methanol to precipitate proteins. Subsequently, the supernatant was analyzed by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry in electrospray negative mode. Mass spectral data were acquired in MSE mode, a technique whereby both precursor and fragment mass spectral are simultaneously acquired by alternating between low and high collision energy (CE) during a single analytical run, to enable metabolite identification. Based on multivariate data analysis, these markers were significantly affected by thermal treatment. Among the 8 potential markers, we identified 7 oxylipids (9-hydroxydecanoic acid, 12-hydroxydodecanoic acid, 2-hydroxymyristic acid, 3-hydroxytetradecanoic acid, 5-hydroxyeicosatetraenoic acid, 3-hydroxyhexadecanoic acid, and 10-hydroxyoctadecanoic acid) and 1 phospholipid (LysoPE, hexadecanoyl-lysophosphatidylethanolamine). The oxylipids seemed to be adequate for distinguishing UHT milk from raw and pasteurized milk. The structures of the 8 potential markers were identified and characterized using informatics software. Our metabolomics workflow provides a fast approach for the identification of various types of milk.

Differentiation of mesenchymal stem cells to support peripheral nerve regeneration in a rat model.

Mesenchymal stem cells (MSCs) support axon regeneration across artificial nerve bridges but their differentiative capacity and ability to promote nerve regeneration remains unclear. In this study, MSCs isolated from bone marrow of Sprague-Dawley rats were characterized by plastic adherence and pluripotency towards mesodermal lineages. Isolated undifferentiated MSCs (uMSCs) were stimulated towards a Schwann cell (SC) phenotype using specific growth factors, and cell marker analysis was performed to verify SC phenotype in vitro. Differentiation resulted in temporally dependent positive immunocytochemical staining for the SC markers, glial fibrillary acidic protein (GFAP), S100, and nerve growth factor receptor (NGFR), with maximal marker expression achieved after 6days of treatment with differentiation media. Quantitative analysis demonstrated that ~50% of differentiated MSCs (dMSCs) have a SC phenotype. Using an indirect co-culture system, we compared the ability of dorsal root ganglion (DRG) cells to extend neurites in indirect contact with uMSCs and dMSCs as compared to SCs. The mean values of the longest length of the DRG neurites were the same for the dMSCs and SCs and significantly higher than the uMSC and DRG mono-culture systems (p < 0.05). In vivo, compared to an empty conduit, dMSC seeded collagen nerve conduits resulted in a greater number of sciatic motoneurons regenerating axons through the conduit into the distal nerve stump. We conclude that bone marrow-derived MSCs differentiate into a SC-phenotype that expresses SC markers transiently and sufficiently to support limited neurite outgrowth in vitro and axonal regeneration equivalent to that of SCs in vitro and in vivo. The nerve autograft remains the most effective conduit for supporting regeneration across nerve gaps.

Rolipram-induced elevation of cAMP or chondroitinase ABC breakdown of inhibitory proteoglycans in the extracellular matrix promotes peripheral nerve regeneration.

The inhibitory growth environment of myelin and extracellular matrix proteoglycans in the central nervous system may be overcome by elevating neuronal cAMP or degrading inhibitory proteoglycans with chondroitinase ABC (ChABC). In this study, we asked whether similar mechanisms operate in peripheral nerve regeneration where effective Wallerian degeneration removes myelin and extracellular proteoglycans slowly. We repaired transected common peroneal (CP) nerve in rats and either elevated cAMP in the axotomized neurons by subcutaneous rolipram, a specific inhibitor of phosphodiesterase IV, and/or promoted degradation of proteoglycans in the distal nerve stump by local ChABC administration. Rolipram treatment significantly increased the number of motoneurons that regenerated axons across the repair site at 1 and 2 weeks, and increased the number of sensory neurons that regenerated axons across the repair site at 2 weeks. Local application of ChABC had a similar effect to rolipram treatment in promoting motor axon regeneration, the effect being no greater when rolipram and ChABC were administered simultaneously. We conclude that blocking inhibitors of axon regeneration by elevating cAMP or degrading proteoglycans in the distal nerve stump promotes peripheral axon regeneration after surgical repair of a transected nerve. It is likely that elevated cAMP is sufficient to encourage axon outgrowth despite the inhibitory growth environment such that simultaneous enzymatic proteoglycan degradation does not promote more axon regeneration than either elevated cAMP or proteoglycan degradation alone.

Monoclonal antibody-defined human pancreatic cancer-associated antigens.

Three pancreatic cancer-associated antigens were characterized by use of monoclonal antibodies in immunobinding studies with various cellular and soluble target antigens, in immunoprecipitation, and in immunoperoxidase staining. C54-0 represents a tumor-associated Mr 122,000 antigen, which appears to be widely distributed on various epithelial tumors and to a lower extent on normal tissue. C1-N3 antigen exhibited a more restricted distribution, reacting with pancreatic and various gastrointestinal tract tumors as well as with chronically inflamed pancreatic tissue. The most specific antigen expression was observed for C1-P83 antigen, found on all exocrine tumors of the pancreas, but not on normal or chronically inflamed pancreatic tissue.