| 1. |
- Acosta, Stefan, et al.
(författare)
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Long-term testosterone stimulation induces hyperplasia in the guinea-pig prostate.
- 2004
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Ingår i: Prostate Cancer and Prostatic Diseases. - : Springer Science and Business Media LLC. - 1476-5608 .- 1365-7852. ; 7:3, s. 227-231
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Tidskriftsartikel (refereegranskat)abstract
- The relation between supraphysiologic circulating testosterone levels and prostatic diseases is unclear and difficult to study in men. Animal models may be advantageous. Based on a pilot study, testosterone enantate 50 mg (n=12) or 25 mg (n=12) was administered to guinea-pigs intramuscularly every 3 weeks, for either 7 or 14 months. The histopathology of the prostate was described. Epithelial hyperplasia was found in 14/21 animals receiving testosterone and in 7/12 very old animals, but no such changes were found in the sham or castrated animals. Testosterone stimulation seems to induce epithelial hyperplasia, but not cancer, in the guinea-pig prostate.
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| 2. |
- Acosta, Stefan, et al.
(författare)
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Neuroendocrine cells and nerves in the prostate of the guinea pig: effects of peripheral denervation and castration
- 2001
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Ingår i: The Prostate. - 0270-4137. ; 46:3, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Neuroendocrine (NE) cells and nerves in the prostate gland are thought to play a central role in the regulation of growth, cellular differentiation and homeostasis of secretory activity. The objective of this experimental study was to describe the effects of peripheral denervation and castration on NE cells and nerves in the guinea pig prostate. METHODS: Guinea pigs underwent sham-operation, unilateral and bilateral hypogastric nerve resection, extirpation of the right anterior major pelvic ganglion (AMPG), autotransplantation of prostatic tissue and castration. Cryostat sections of prostatic tissue were examined with immunohistochemistry by using serotonin (5-HT) and chromogranin A (CgA) and various neuropeptides. RESULTS: The number of 5-HT-IR NE cells was four-fold higher than CgA-IR NE cells. The innervation pattern was uniform throughout the gland with subepithelial nerves in close proximity to NE cells. Autotransplants of prostatic tissue showed total loss of nerves, but the number and morphology of 5-HT-IR NE cells were unaltered. Extirpation of the right AMPG showed significant reduction in prostate weight, decreased density of nerve terminals in the superior part of the ipsilateral prostate, whereas the number and morphological feature of 5-HT-IR NE cells remained unaffected in the entire prostate. Castration induced atrophy of the gland with a significant reduction in weight (unpaired t-test, P < 0.001), but without effect upon 5-HT-IR NE cells. CONCLUSIONS: The guinea pig seems to be a useful animal model for studies on the role of the NE cells in the prostate. NE cells seem to be independent of innervation and androgens. It seems that other factors influence the NE cell population to a greater extent.
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| 3. |
- Dabek, M, et al.
(författare)
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alpha-ketoglutarate (AKG) absorption from pig intestine and plasma pharmacokinetics
- 2005
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Ingår i: Journal of Animal Physiology and Animal Nutrition. - : Wiley. - 0931-2439 .- 1439-0396. ; 89:11-12, s. 419-426
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Tidskriftsartikel (refereegranskat)abstract
- To study the absorption, metabolism and kinetics, the AKG ( in different concentrations) was administered intravenously, intra-portally, orally and directly into the ileum or duodenum of pigs, chronically fitted with portal and jugular catheters and T-shaped cannula at the duodenum and ileum. Additionally, this study was conducted to determine the influence of low pH, Fe2+ or/ and SO42- on AKG gut absorption and conversely FeSO4 and FeSO4/AKG on Fe2+ gut absorption. It is concluded that AKG was significantly better absorbed from the upper small intestine than from the distal sections. Furthermore, low pH, Fe2+ and/or SO42- ions enhanced AKG absorption. The AKG administered to the portal vein was rapidly eliminated from the blood (half-life less than 5 min). The short lifetime for AKG is probably dependent on quick metabolism in the enteorcyetes and liver. However, the prolonged half-life can be related to its low AKG blood concentration. The Fe2+ concentrations in blood increased after FeSO4 and FeSO4/AKG duodenal infusion. The implication of above observations is important for practical application of the AKG in animal and human nutrition as well in medicine.
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| 4. |
- Arciszewski, Marcin, et al.
(författare)
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Lipopolysaccharide induces cell death in cultured porcine myenteric neurons.
- 2005
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Ingår i: Digestive Diseases and Sciences. - : Springer Science and Business Media LLC. - 1573-2568 .- 0163-2116. ; 50:9, s. 1661-1668
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Tidskriftsartikel (refereegranskat)abstract
- Enteric bacteria execute, via lipopolysaccharide (LPS), a pathogenic role in intestinal inflammation. The effects of LPS on survival and neurotransmitter expression in cultured porcine myenteric neurons were investigated. Myenteric neurons were isolated and cultured for 6 days in medium, in LPS (100 ng/ml) with or without α-ketoglutarate or the nitric oxide synthase (NOS) inhibitor L-NAME, in α-ketoglutarate or in the NO donor SNAP. Neuronal survival and expression of vasoactive intestinal peptide (VIP) and NOS were evaluated by immunocytochemistry. Addition of LPS significantly decreased neuronal survival; only 40% survived, compared to controls run in parallel. The LPS-induced neurotoxic effect was not counteracted by the simultaneous presence of α-ketoglutarate or L-NAME. Either SNAP or α-ketoglutarate influenced neuronal survival. Culturing, particularly in the presence of LPS, markedly increased the proportion of VIP-immunoreactive neurons; NOS-immunoreactive neurons were unchanged. The reported LPS-induced neurotoxicity indicates loss of enteric neurons as a consequence of intestinal inflammation.
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| 5. |
- Arévalo Sureda, Ester, et al.
(författare)
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Maturation of the intestinal epithelial barrier in neonatal rats coincides with decreased FcRn expression, replacement of vacuolated enterocytes and changed Blimp-1 expression
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Background: The intestinal barrier is immature in newborn mammals allowing for transfer of bioactive macromolecules, e.g. protecting antibodies, from mother's milk to the blood circulation and in neonatal rodents lasts until weaning. This passage involves the neonatal-Fc-receptor (FcRn) binding IgG in the proximal and highly endocytic vacuolated enterocytes in the distal immature small intestine (SI). Recent studies have suggested an involvement of the transcription factor B-lymphocyte-induced maturation-protein-1 (Blimp-1) in the regulation of SI maturation in mice. Hence, the objective of the present study was to monitor the development of the intestinal barrier function, in relation to Blimp-1 expression during both natural and precociously induced intestinal maturation in rats. Results: During the suckling period IgG plasma levels increased, while after gut closure it temporarily decreased. This corresponded to a high expression of FcRn in the proximal SI epithelium and the presence of vacuolated enterocytes in the distal SI. The immature foetal-type epithelium was replaced after weaning or induced precocious maturation, by an adult-type epithelium with FcRnneg cells in the proximal and by non-vacuolated enterocytes in the distal SI. In parallel to this epithelial shift, Blimp-1 expression decreased in the distal SI. Conclusion: The switch from foetal- to adult-type epithelium, with decreased proximal expression of FcRn and distal replacement of vacuolated enterocytes, was concurrent in the two SI regions and could be used for monitoring SI maturation in the rat. The changes in expression of Blimp-1 in the distal SI epithelium followed the maturation pattern.
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| 6. |
- Bayliak, Maria M., et al.
(författare)
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Dietary alpha-ketoglutarate increases cold tolerance in Drosophila melanogaster and enhances protein pool and antioxidant defense in sex-specific manner
- 2016
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Ingår i: Journal of Thermal Biology. - : Elsevier BV. - 0306-4565. ; 60, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Alpha-ketoglutarate (AKG) is an important intermediate in Krebs cycle which bridges the metabolism of amino acids and carbohydrates. Its effects as a dietary supplement on cold tolerance were studied in Drosophila melanogaster Canton S. Two-day-old adult flies fed at larval and adult stages with AKG at moderate concentrations (5-10 mM) recovered faster from chill coma (0 °C for 15 min or 3 h) than control ones. The beneficial effect of AKG on chill coma recovery was not found at its higher concentrations, which suggests hormetic like action of this keto acid. Time of 50% observed mortality after 2 h recovery from continuous cold exposure (-1 °C for 3-31 h) (LTi50) was higher for flies reared on 10 mM AKG compared with control ones, showing that the diet with AKG enhanced insect cold tolerance. In parallel with enhancement of cold tolerance, dietary AKG improved fly locomotor activity. Metabolic effects of AKG differed partly in males and females. In males fed on AKG, there were no differences in total protein and free amino acid levels, but the total antioxidant capacity, catalase activity and low molecular mass thiol content were higher than in control animals. In females, dietary AKG promoted higher total antioxidant capacity and higher levels of proteins, total amino acids, proline and low molecular mass thiols. The levels of lipid peroxides were lower in both fly sexes reared on AKG as compared with control ones. We conclude that both enhancement of antioxidant system capacity and synthesis of amino acids can be important for AKG-promoted cold tolerance in D. melanogaster. The involvement of AKG in metabolic pathways of Drosophila males and females is discussed.
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| 7. |
- Berthelot, V, et al.
(författare)
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Hepatic metabolism of propionate and methylmalonate in growing lambs
- 2002
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Ingår i: Livestock Production Science. - 0301-6226. ; 74:1, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- The hepatic extraction ratio or propionate and the net hepatic flux of methylmalonate (MMA) were investigated in six Suffolk lambs (32.7 +/- 1.7 kg BW) implanted with catheters in a mesenteric artery and in the portal, hepatic, and ruminal veins and a cannula in the rumen. The lambs were fed a pelleted barley-based diet (1.1 kg DM per day) and subjected to three intravenous infusion protocols separated by at least 7 days: saline (C; control), butyrate (B; 0.2 mmol/h/kg BW) or lactate (L; 0.96 mmol/h/kg BW). The solutions were infused continuously into the ruminal vein for 13 h. At the same time as the intravenous infusion treatments, propionate (1.78 mmol/h/kg BW) was infused intraruminally for 4 h starting 4 h after the initiation of the experimental protocol. Arterial, portal and hepatic blood samples were obtained during the last 10 h of the infusion protocol. Blood flow was measured by down stream dilution of p-aminohippuric acid. The hepatic extraction ratio of propionate decreased from 85 +/- 3 to 75 +/- 1% after intraruminal infusion of propionate and the net splanchnic appearance of propionate increased threefold with the doubling of the net portal appearance of propionate. Intravenous infusion of lactate or butyrate did not affect the hepatic extraction ratio or net splanchnic flux of propionate. The net portal appearance, net hepatic flux and net splanchnic appearance of MMA were not (P > 0.10) different from zero in all situations. The arterial concentration of MMA increased with increasing absorption rate of propionate but remained below 2 mumol/l throughout the experiment. The results of the present study do not support the hypothesis that the MMA possibly incorporated into methyl-branched chain fatty acids in adipose tissue of intensively-reared lambs is of hepatic origin.
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| 8. |
- Brueggemann, Dagmar A., et al.
(författare)
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Muscle contraction and force: the importance of an ancillary network, nutrient supply and waste removal
- 2008
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 9:8, s. 1472-1488
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Tidskriftsartikel (refereegranskat)abstract
- Muscle contraction studies often focus solely on myofibres and the proteins known to be involved in the processes of sarcomere shortening and cross-bridge cycling, but skeletal muscle also comprises a very elaborate ancillary network of capillaries, which not only play a vital role in terms of nutrient delivery and waste product removal, but are also tethered to surrounding fibres by collagen "wires". This paper therefore addresses aspects of the ancillary network of skeletal muscle at both a microscopic and functional level in order to better understand its role holistically as a considerable contributor to force transfer within muscular tissue.
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| 9. |
- Buddington, KK, et al.
(författare)
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A non-terminal surgical procedure for chronic collection of exocrine pancreatic secretions from unrestrained dogs (Canis familiaris)
- 2002
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Ingår i: Contemporary Topics in Laboratory Animal Science. - 1060-0558. ; 41:1, s. 31-37
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Tidskriftsartikel (refereegranskat)abstract
- The ability of dogs to adaptively modulate secretion by the exocrine pancreas to match changes in the amounts and sources of macronutrients is poorly understood. We evaluated the use of re-entrant pancreatic catheters as a non-terminal, temporary approach for the chronic collection of exocrine pancreatic secretion using unrestrained dogs fed diets differing in composition. Re-entrant catheters were surgically placed in the accessory pancreatic duct of two adult mongrel dogs. Secretions were collected for 40 days, during which the dogs were fed three diets with different amounts and sources of macronutrients. The volume of secretion was recorded, protein content was measured, and the activities of trypsin, chymotrypsin, amylase, and lipase were assayed. Inter-dog variation was detected for the volume of secretion (ml/h) but not for protein content (mg/ml) or activities (U/ml) of the enzymes. The volume and composition of the secretion differed among diets. The responses were delayed about 4 days, were transient, and did not coincide with the changes in diet composition. We found that the re-entrant catheters were suitable for studying the exocrine pancreatic secretion of dogs. Our findings were inconclusive about the influence of diet but suggested that adult dogs have a limited and nonspecific response of pancreatic secretion.
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| 10. |
- Buddington, Karyl K., et al.
(författare)
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Selective and Concentrative Enteropancreatic Recirculation of Antibiotics by Pigs
- 2024
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Ingår i: Antibiotics. - 2079-6382. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Antibiotics that are efficacious for infectious pancreatitis are present in pancreatic exocrine secretion (PES) after intravenous administration and above minimal inhibitory concentrations. We measured concentrations of four antibiotics by tandem liquid chromatography–mass spectroscopy in plasma and PES after enteral administration to juvenile pigs with jugular catheters and re-entrant pancreatic-duodenal catheters. Nystatin, which is not absorbed by the intestine nor used for infectious pancreatitis (negative control), was not detected in plasma or PES. Concentrations of amoxicillin increased in plasma after administration (p = 0.035), but not in PES (p = 0.51). Metronidazole and enrofloxacin that are used for infectious pancreatitis increased in plasma after enteral administration and even more so in PES, with concentrations in PES averaging 3.1 (±0.5)- and 2.3 (±0.6)-fold higher than in plasma, respectively (p′s < 0.001). The increase in enrofloxacin in PES relative to plasma was lower after intramuscular administration (1.8 ± 0.5; p = 0.001). The present results demonstrate the presence of a selective and concentrative enteropancreatic pathway of secretion for some antibiotics. Unlike the regulated secretion of bile, the constitutive secretion of PES and intestinal reabsorption may provide a continuous exposure of pancreas tissue and the small intestine to recirculated antibiotics and potentially other therapeutic molecules. There is a need to better understand the enteropancreatic recirculation of antibiotics and the associated mechanisms.
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