| 1. |
- Augustin, K, et al.
(författare)
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Green tea extracts lower serum folates in rats at very high dietary concentrations only and do not affect plasma folates in a human pilot study.
- 2009
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Ingår i: Journal of Physiology and Pharmacology. - 0867-5910 .- 1899-1505. ; 60:3, s. 103-108
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Tidskriftsartikel (refereegranskat)abstract
- Green tea catechins (GTC) have been shown to inhibit the activities of enzymes involved in folate uptake. Hence, regular green tea drinkers may be at risk of impaired folate status. The present experiments aimed at studying the impact of dietary GTC on folate concentrations and metabolism. In a human pilot study (parallel design) healthy men consumed for 3 weeks 6 capsules (approximately 670 mg GTC) per day (2 capsules with each principal meal) containing aqueous extracts of the leaves of Camellia sinensis (n=17) or placebo (n=16). No differences in plasma folate concentrations were observed between treatments. We further fed groups of 10 male rats diets fortified with 0, 0.05, 0.5, 1, or 5 g GTC/kg for 6 weeks. Only at the highest intake, GTC significantly decreased serum 5-methyl-tetrahydrofolate concentrations in rats, while mRNA concentrations of reduced folate carrier, proton-coupled folate transporter/heme carrier protein 1, and dihydrofolate reductase (DHFR) remained unchanged in intestinal mucosa. Using an in vitro enzyme activity assay, we observed a time- and dose-dependent inhibition of DHFR activity by epigallocatechin gallate and a green tea extract. Our data suggest that regular green tea consumption is unlikely to impair folate status in healthy males, despite the DHFR inhibitory activity of GTC.
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| 2. |
- Björnström, Karin, 1971-, et al.
(författare)
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Characterisation of the signal transduction cascade caused by propofol in rat neurons : From the GABAA receptor to the cytoskeleton
- 2008
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Ingår i: Journal of Physiology and Pharmacology. - 0867-5910 .- 1899-1505. ; 59:3, s. 617-632
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Tidskriftsartikel (refereegranskat)abstract
- The anaesthetic propofol interacts with the GABAA receptor, but its cellular signalling pathways are not fully understood. Propofol causes reorganisation of the actin cytoskeleton into ring structures in neurons. Is this reorganisation a specific effect of propofol as apposed to GABA, and which cellular pathways are involved? We used fluorescence-marked actin in cultured rat neurons to evaluate the percentage of actin rings caused by propofol or GABA in combination with rho, rho kinase (ROK), PI3-kinase or tyrosine kinase inhibitors, with or without the presence of extracellular calcium. Confocal microscopy was performed on propofol-stimulated cells and changes in actin between cellular compartments were studied with Western blot. Propofol (3 μg·ml-1), but not GABA (5 μM), caused transcellular actin ring formation, that was dependent on influx of extracellular calcium and blocked by rho, ROK, PI3-kinase or tyrosine kinase inhibitors. Propofol uses rho/ROK to translocate actin from the cytoskeleton to the membrane and its actin ring formation is dependent on an interaction site close to the GABA site on the GABAA receptor. GABA does not cause actin rings, implying that this is a specific effect of propofol.
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| 3. |
- Fedkiv, Olexandr, et al.
(författare)
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Growth is dependent on the exocrine pancreas function in young weaners but not in growing-finishing pigs
- 2009
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Ingår i: Journal of Physiology and Pharmacology. - 0867-5910. ; 60:Suppl. 3, s. 55-59
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Konferensbidrag (refereegranskat)abstract
- A correlation between the exocrine pancreatic function and growth has been previously demonstrated in growing pigs but the data are inconsistent. This was investigated by studying the growth performance of pigs with exocrine pancreatic insufficiency (EPI) at different ages and maintained under similar conditions. Twelve 7 week old (10.5 +/- 1.3 kg) weaners, and twelve 16 week old (43 +/- 5 kg) growing-finishing pigs were used in the experiments, and 6 pigs from each group were operated and pancreatic duct-ligated. Starting at 3-5 weeks after the operation, when EPI had developed, weekly recordings of feed consumption and growth were done before, during and after feed supplementation with porcine pancreatin (Creon (R) 10000). In weaner pigs, EPI caused growth arrest while it did not affect the growth of older pigs, as compared to respective un-operated groups of pigs. The daily feed consumption (DFC) was lower in the weaner EPI-pigs while it was similar in the growing-finishing EPI-pigs, as compared to un-operated pigs. Feed supplementation with Creon (R) improved the DFC and growth in both the EPI and un-operated pigs. In conclusion, the results showed the importance of the exocrine pancreatic function for growth in weaner pigs, while in older animals it played a minor role in growth. Feed supplementation with pancreatin increased the appetite and ensured an improved feed conversion.
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| 4. |
- Harrison, A. P., et al.
(författare)
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Biological effects of 2-oxoglutarate with particular emphasis on the regulation of protein, mineral and lipid absorption/metabolism, muscle performance, kidney function, bone formation and cancerogenesis, all viewed from a healthy ageing perspective state of the art - review article
- 2008
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Ingår i: JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY. - 0867-5910. ; 59, s. 91-106
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Konferensbidrag (refereegranskat)abstract
- The fact that men and women are living longer than they have ever done before is something in which we can all rejoice. However, the process of ageing is associated with changes in skeletal, muscular, gastrointestinal, neural hormonal and metabolic processes that seriously affect an individual's performance and quality of life. Indeed, Such changes can be contributory to a loss of independence in the elderly. This state-of-the art address highlights the main changes found to occur with ageing whilst simultaneously reporting findings of in vivo and in vitro studies designed to elucidate the potential of the Krebs cycle intermediate - alpha-ketoglutaric acid (AKG) in protecting elderly body systems from failing and degradation, The topics of paramount importance include impaired bone structure and strength, amino acid and mineral absorption, muscle performance, as well as highlighting the role of Krebs cycle intermediates in the debilitating changes that occur with end-stage renal failure and the regulation of the lipid metabolism. Finally, focus will be given to the role of 2-oxoglutarate as a potent protective factor in connection with the development of malignant cells in the body.
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| 5. |
- Hellmén, Eva
(författare)
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Transcriptomic profile of two canine mammary cancer cell lines with different proliferative and anti-apoptotic potential
- 2009
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Ingår i: Journal of Physiology and Pharmacology. - 0867-5910 .- 1899-1505. ; 60, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to identify the genes responsible for the high growth rate and antiapoptotic potential in selected canine mammary cancer cells. cDNA canine microarrays were used to compare the transcriptome in simple carcinoma CMT-U27 and spindle-cell tumor CMT-U309 cell lines. In CMT- U27 cell line the growth rate (shorter cell cycle), anti-apoptotic potential (higher expression of Bcl-2) was higher and spontaneous and induced apoptosis was lower. Comparison of transcriptomes revealed 333 genes which expression differed similarly. We focused on genes involved in cell proliferation, adhesion and apoptosis, and selected 29 of them. The high growth rate and anti-apoptotic potential in CMT-U27 cells was associated with enhanced expression of genes (at the level of transcripts) involved in Ca(2+) signaling pathway (Calmodulin 1, 2, 3 and SPSB2) and growth hormone cellular pathway. The low-proliferative and pro-apoptotic phenotype of CMT-U309 cells was more dependent on TGF beta, neuregulin I pathways and adhesion-related molecules.
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| 6. |
- Rügheimer, Louise, et al.
(författare)
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Renal Hyaluronan Content During Experimental Uncontrolled Diabetes in Rats
- 2008
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Ingår i: Journal of Physiology and Pharmacology. - 0867-5910 .- 1899-1505. ; 59:1, s. 115-128
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Tidskriftsartikel (refereegranskat)abstract
- With diabetes mellitus, the ability of the kidneys to maintain fluid balance is affected. Hyperglycaemia increases production of hyaluronan in cultured kidney cells implying that diabetes promotes induction of hyaluronan in the kidney. The aim of the present study was to determine if the interstitial matrix component hyaluronan is differently distributed within the kidney in diabetic rats compared to non-diabetic rats. Furthermore, to test if diabetic rats are able to respond with diuresis upon a hypotonic fluid load. The normal heterogeneous intrarenal distribution of hyaluronan was confirmed in non-diabetic control rats, with 60-fold more in the papilla than in the cortex. In diabetic animals, the cortical hyaluronan was unaffected but the papillary hyaluronan content was 3-fold higher than in non-diabetic rats. This increase correlated with a more than three-fold induction of the papillary hyaluronansynthase 2 mRNA expression. In non-diabetic animals, 2 h water loading increased papillary hyaluronan (+93%) and diuresis (17-fold). In diabetic animals, baseline diuresis was 8-fold higher than in non-diabetic animals, which correlated with hyperglycaemia, glucosuria and proteinuria. Water loading in diabetic animals did not further increase papillary hyaluronan or diuresis: the urine flow rate decreased. To conclude, papillary hyaluronan is elevated in diabetic rats, which coincides with induction of hyaluronan-synthase 2 mRNA, hyperglycaemia, glucosuria, proteinuria and overt diuresis. The inability to respond to a water load with further diuresis may be related to the already elevated papillary hyaluronan and the inability to change hyaluronan during water loading.
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| 7. |
- Sahlin, Kent, et al.
(författare)
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Turning down lipid oxidation during heavy exercise--what is the mechanism?
- 2008
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Ingår i: Journal of Physiology and Pharmacology. - 0867-5910 .- 1899-1505. ; 59:4, s. 19-30
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Tidskriftsartikel (refereegranskat)abstract
- A high potential for lipid oxidation is a sign of metabolic fitness and is important not only for exercise performance but also for health promotion. Despite considerable progress during recent years, our understanding of how lipid oxidation is controlled remains unclear. The rate of lipid oxidation reaches a peak at 50-60% of (V) over dotO(2) (max) after which the contribution of lipids decreases both in relative and absolute terms. In the high-intensity domain (> 60% (V) over dotO(2 max)), there is a pronounced decrease in energy state, which will stimulate the glycolytic rate in excess of the substrate requirements of mitochondrial oxidative processes. Accumulation of glycolytic products will impair lipid oxidation through an interaction with the carnitine-mediated transfer of FA into mitochondria. Another potential site of control is Acyl-CoA synthetase (ACS), which is the initial step in FA catabolism. The activity of ACS may be under control of CoASH and energy state. There is evidence that additional control points exist beyond mitochondrial influx of fatty acids. The electron transport chain (ETC) with associated feed-back control by redox state is one suggested candidate. In this review it is suggested that the control of FA oxidation during heavy exercise is distributed between ACS, CPT1, and ETC.
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| 8. |
- Tobin, Gunnar, 1954, et al.
(författare)
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Muscarinic receptor subtypes in the alimentary tract
- 2009
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Ingår i: JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY. - 0867-5910. ; 60:1, s. 3-21
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Forskningsöversikt (refereegranskat)abstract
- Acetylcholine is a transmitter in preganglionic autonomic and postganglionic parasympathetic nerves and a non-neuronal paracrine mediator in the alimentary tract. Acetylcholine is involved in the control of almost any function within these organ systems, and almost every cell type expresses multiple muscarinic receptor subtypes. Although muscarinic receptors at non-neuronal effector cells commonly are of the M3 subtype, the population usually consists of a mixture of muscarinic receptor subtypes often co-acting postsynaptically. However, the pattern of heterogeneity of varies between different tissues. The population in gland parenchymal tissue often consists of a mixture of M1 and M3 receptors, smooth muscle tissue of the gut of M2 and M3, blood vessels of M1, M3, M4 and M5 and neuronal cells of M1 and M4. Nitric oxide production, effects on inflammation and proliferation may involve M1, M3 and M5 receptors. Muscarinic receptors expressed on nerve terminals may indirectly modulate the responses by inhibition or facilitation of neuronal transmission in the autonomic nervous system. The present review describes signalling mechanisms, expression and functional effects of muscarinic receptors in salivary glands and in the gastrointestinal tract.
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