N-6 polyunsaturated fatty acids (PUFAs) may be associated with increased risk of colon cancer, whereas n-3 PUFAs may have a protective effect. We examined the effects of docosahexaenoic acid (DHA), eicosapentaenoic acid and arachidonic acid on the colon carcinoma cell lines SW480 derived from a primary tumour, and SW620 derived from a metastasis of the same tumour. DHA had the strongest growth-inhibitory effect on both cell lines. SW620 was relatively more growth-inhibited than SW480, but SW620 also had the highest growth rate in the absence of PUFAs. Flow cytometry revealed an increase in the fraction of cells in the G 2 ⁄ M phase of the cell cycle, particularly for SW620 cells. Growth inhibition was apparently not caused by increased lipid peroxidation, reduced glutathione or low activity of glutathione peroxidase. Transmission electron microscopy revealed formation of cytoplasmic lipid droplets after DHA treatment. In SW620 cells an eightfold increase in total cholesteryl esters and a 190-fold increase in DHA-containing cholesteryl esters were observed after DHA treatment. In contrast, SW480 cells accumulated DHA-enriched triglycerides. Arachidonic acid accumulated in a similar manner, whereas the nontoxic oleic acid was mainly incorporated in triglycerides in both cell lines. Interestingly, nuclear sterol regulatory element-binding protein 1 (nSREBP1), recently associated with cell growth regulation, was downregulated after DHA treatment in both cell lines. Our results demonstrate cell-specific mechanisms for the processing and storage of cytotoxic PUFAs in closely related cell lines, and suggest downregulation of nSREBP1 as a possible contributor to the growth inhibitory effect of DHA.

Microdialysis of glycerol provides information about the extent and severity of intestinal damage after ischemia and about the ensuing recovery. The gut lumen is to be preferred as a site for placement of microdialysis catheters.

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X-ray microanalysis has been performed on freeze-dried cryosections of normal, hyperplastic, and neoplastic human prostates. Needle biopsies from prostates suspected to be malignant were collected from ten patients. Seven of these patients had fully developed nodular hyperplasia, whereas the remaining three specimens were histologically classified as moderately differentiated adenocarcinomas. Prostates with normal light microscopic appearance were obtained from two brain-dead kidney donors. The concentration of calcium in secretory vesicles was found to be several orders of magnitude higher than the concentration of magnesium and zinc in all of the glands studied, which is consistent with calcium being the major cation secreted by the prostatic acinar cells. Some elderly prostates and neoplastic prostates revealed even lower mean zinc:calcium ratios in secretory vesicles. Even though both elements varied considerably, the wide variation of the zinc:calcium ratios was due mainly to variations in the concentration of zinc. Large, electron-dense bodies occasionally were found in the cytoplasm of prostatic acinar cells. These bodies contained high concentrations of sulphur which by far was the dominating element.

The purpose of the present study was to use magnetic resonance imaging (MRI) as a tool for monitoring transplant-mediated repair of the adult rat visual pathway. We labelled rat olfactory ensheathing cells (OECs) using micron-sized particles of iron oxide (MPIO) and transplanted them by: i) intravitreal injection (ivit) and ii) intra-optic nerve (ON) injection (iON) in adult rats with ON crush (ONC) injury. We applied T(2)-weighted MRI and manganese-enhanced MRI (MEMRI) to visualise transplanted cells and ON axons at specific times after injury and cell engraftment. Our findings demonstrate that ivit MPIO-labelled OECs are unequivocally detected by T(2)-weighted MRI in vivo and that the T(1)-weighted 3D FLASH sequence applied for MEMRI facilitates simultaneous visualisation of Mn(2+-) enhanced regenerating retinal ganglion cell (RGC) axons and MPIO-labelled OEC grafts. Furthermore, analysis of MRI data and ultrastructural findings supports the hypothesis that iON OEC transplants mediate regeneration and remyelination of RGC axons post injury.