| 1. |
- Håkansson, H., et al.
(författare)
-
In vivo and in vitro toxicity of fractionated fish lipids, with particular regard to their content of chlorinated organic compounds
- 1991
-
Ingår i: Pharmacology and Toxicology. - : Wiley. - 0901-9928 .- 1600-0773. ; 69:6, s. 459-471
-
Tidskriftsartikel (refereegranskat)abstract
- Six different lipid matrices (the intact lipid (IL), four lipid fractions with different polarity, and the free fatty acids (FFAs) obtained by hydrolysis of the triacylglycerol (TAG) containing fraction) were obtained from salmon (Salmo salar) and eel (Anguilla anguilla), each collected at a contaminated and a comparatively uncontaminated catch site along the coast of Scandinavia. The lipid matrices were studied in toxicological test systems representing various biological functions of different organ systems from several species and trophic levels. The results were evaluated with particular respect to the concentrations of extractable organically bound chlorine (EOCl) in the matrices tested. In some test systems, the specimens with a higher EOCl concentration appeared to be more toxic. For example, the TAG containing fraction (F2) from Idefjord eel, having a higher EOCl content than F2 from Oslofjord eel, reduced the number and hatchability of eggs laid by zebrafish. Both IL and F2 of Idefjord eel increased mortality and reduced the oxygen/nitrogen-ratio in blue mussels. Non-polar compounds (F1) from Bothnian Sea salmon induced 7-ethoxyresurofin O-deethylase (EROD) activity in rainbow trout hepatocytes, whereas F1 from Senja salmon did not. F1 from Bothnian Sea salmon also reduced the number of T-cells in foetal mouse thymus anlagen in vitro compared with the cell number in anlagen exposed to F1 from Senja salmon. A positive correlation between EOCl concentration and test response was found for EROD activity in rainbow trout hepatocytes and for ATP-leakage in Erlich ascites tumour cells when testing the phospolipid containing fraction (F4). However, in most test systems the fish oils, irrespective of EOCl content, were of low toxicity, and the observed effects need to be verified in future studies.
|
|
| 2. |
- Granstam, S O, et al.
(författare)
-
Effects of cigarette smoke and nicotine on duodenal bicarbonate secretion in the rabbit and the rat.
- 1990
-
Ingår i: Journal of Clinical Gastroenterology. - 0192-0790 .- 1539-2031. ; 12 Suppl 1, s. S19-24
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of short-time exposure to cigarette smoke on duodenal mucosal bicarbonate secretion were studied in anesthetized rabbits and rats. The bicarbonate secretion was measured by continuous titration of recirculating luminal perfusate. In artificially ventilated rabbits, intermittent exposure to cigarette smoke during two 10-min periods caused a marked (approximately 40%) decrease (p less than 0.01) in duodenal bicarbonate secretion. After the exposures, secretion gradually recovered and had returned to the pre-exposure rate after 50 min. The decrease in secretion was associated with decreases in heart rate (approximately 15%) and blood pressure (approximately 30%) that, however, were of shorter duration. Neither reduced amounts of smoke (1/6 or 1/3) nor nicotine (25-1,000 micrograms/kg, intravenously) had any major effect on the bicarbonate secretion. In the spontaneously breathing rat, smoke was administered for 1-2 breaths every 30 s during a 5-min period. This exposure resulted in a significant (p less than 0.05) decrease in bicarbonate secretion and some increase in the blood pressure. Exposure to smoke had no effect on the secretion in rats with both splanchnic nerves cut, suggesting neural sympathetic mediation of the smoke-induced inhibition.
|
|
| 3. |
- Holm, Lena, et al.
(författare)
-
Duodenal alkaline secretion in rabbits : influence of artificial ventilation.
- 1990
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 138:4, s. 471-8
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of artificial ventilation on duodenal alkaline secretion and blood flow was studied in sodium pentobarbital-anaesthetized rabbits. A duodenal segment (approximately 3 cm) was cannulated in situ and continuously perfused with isotonic saline, and the bicarbonate secretion was titrated by pH-stat. Compared with the spontaneous breathing state, artificial ventilation improved the respiratory status of the animal, increasing Po2 and decreasing both Pco2 and plasma bicarbonate. Duodenal blood flow as measured with laser-Doppler flowmetry was not altered but the alkaline secretion was reduced. Pretreatment with the alpha 2-adrenoceptor antagonist yohimbine (0.5 mg kg-1 i.v., followed by 0.5 mg kg-1 h-1 i.v.) or the ganglionic blocker hexamethonium (10 mg kg-1 i.v.) did not affect the decline in duodenal alkaline secretion in response to artificial ventilation. Nor did these pretreatments affect the changes in plasma bicarbonate and Pco2 or significantly alter the blood flow. Increasing Pco2 in the respirator air increased the plasma Pco2 and bicarbonate concentration as well as the duodenal bicarbonate secretion. Pretreatment with the carbonic anhydrase inhibitor acetazolamide (80 mg kg-1 i.v.) reduced the bicarbonate secretion, and artificial ventilation induced a further reduction. Increasing Pco2 in the respirator in the animals pretreated with acetazolamide did not affect the bicarbonate secretion. Duodenal alkaline secretion was thus always reduced on artificial ventilation. The mechanism for this reduction does not seem to involve the sympathetic nervous system or the blood flow, but appears to be the consequence of alterations in the plasma concentration of bicarbonate and the plasma Pco2.
|
|
| 4. |
- Holm, Lena, et al.
(författare)
-
Microscopy of acid transport at the gastric surface in vivo.
- 1990
-
Ingår i: Journal of internal medicine. Supplement. - 0955-7873. ; 732, s. 91-5
-
Tidskriftsartikel (refereegranskat)abstract
- In vivo microscopy of the gastric surface, and pH-sensitive dyes, were used to study the movement of acid formed in the gastric crypts across the mucus layer adherent to the gastric surface and into the lumen. Rats were anaesthetized and the stomach gently exteriorized. When the pH-sensitive dye Congo red was applied luminally to stain the gel, predominantly red spots (pH greater than 5) and occasional blue spots (pH less than 3), located above the outlets of the crypts, were observed in spontaneously-secreting mucosae. Maximal stimulation of acid secretion (pentagastrin, 40 micrograms kg-1 h-1) resulted in the appearance only of blue spots, but the pH in the mucus gel between the crypts remained more alkaline, as indicated by pink staining. The fluorescence dye acridine orange was injected intravenously to an estimated blood concentration of 10(-5)M in another type of experiment. This dye is concentrated and secreted by the parietal cells. Pronounced fluorescence was observed within spots of the gastric surface corresponding to the outlets of the gastric crypts, but no fluorescence was detected outside these areas. The results obtained with both dyes strongly suggest that acid (and pepsin) is transported across the mucus gel only at restricted sites.
|
|
| 5. |
- Holm, William, et al.
(författare)
-
Negative magnetoresistance in an yba2cu3O7-delta thin-film
- 1994
-
Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 194, s. 2309-2310
-
Tidskriftsartikel (refereegranskat)abstract
- Negative magnetoresistance was observed in a thin YBa2Cu3O7-delta film which could be correlated with the presence of magnetic impurities. After empirical compensation for this effect the fluctuation conductivity was well described by the Aronov-Hikami-Larkin theory.
|
|
| 6. |
|
|
| 7. |
- Lundberg, G, et al.
(författare)
-
Inmatning av sebrafisk, Brachydanio rerio, med halogenerade substanser extraherade från lax och ål. Studier av bioackumulering och reproduktionskapacitet.
- 1992
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fiskoljor extraherades från ål (Anguilla anguilla) och lax (Salmo salar). Fiskarna var fångade i både förorenade och relativt opåverkade områden. Toxiciteten av oljorna samt en fraktion (triacylglyceroler och fria fettsyror) av oljorna testades med avseende på effekter orsakade av Extraherbar Organiskt bunden Klor (EOCl). Sebrafiskhonor (Brachydanio rerio) utfodrades med frystorkade mygglarver som kontaminerats med de olika fiskoljorna och fraktionerna varefter bioackumulering av EOCl och reproduktionskapacitet (antal lagda ägg och kläckningsprocent) studerades. Den fraktionerade oljan från ål fångad i ett förorenat område var mer toxisk än motsvarande fraktion från ett relativt opåverkat område. Utfodring med de ursprungliga fiskoljorna gav inga skillnader i reproduktionskapacitet trots skillnader i halten EOCl. Analyserad halt EOCl i oljorna visade god korrelation med koncentrationerna i oljorna även om upptagseffektiviteten varierade för de olika oljorna. De funna effekterna kunde inte enbart förklaras av EOCl-intaget men utfodringsförsöket visade ändå att exponering för kontaminerat foder är en relevant metod för att studera biologiska effekter orsakade av lipofila ämnen.
|
|
| 8. |
|
|
| 9. |
- Mårin, P, et al.
(författare)
-
The morphology and metabolism of intraabdominal adipose tissue in men.
- 1992
-
Ingår i: Metabolism: clinical and experimental. - 0026-0495. ; 41:11, s. 1242-8
-
Tidskriftsartikel (refereegranskat)abstract
- Mass, morphology, and metabolism of total adipose tissue and its subcutaneous, visceral, and retroperitoneal subcompartments were examined in 16 men with a wide variation of total body fat. Computerized tomography (CT) scans showed that the intraabdominal fat mass comprised approximately 20% of total fat mass. Visceral and retroperitoneal fat masses were approximately 80% and 20% of total intraabdominal fat mass, respectively. Enlargement of intraabdominal fat depots was due to a parallel adipocyte enlargement only. Direct significant correlations were found between these adipose tissue masses and blood glucose and plasma insulin levels, blood pressure, and liver function tests, while glucose disposal rate during euglycemic glucose clamp measurements at submaximal insulin concentrations (GDR), plasma testosterone, and sex hormone-binding globulin concentrations correlated negatively. The correlations for glucose, insulin, and GDR were strongest with visceral fat mass. Adipose tissue lipid uptake, measured after oral administration of labeled oleic acid in triglyceride, was approximately 50% higher in omental than in subcutaneous adipose tissues. Adipocytes from omental fat also showed a higher lipolytic sensitivity and responsiveness to catecholamines. Furthermore, these adipocytes were less sensitive to the antilipolytic effects of insulin. Both lipid uptake and lipolytic sensitivity and responsiveness showed strong correlations (r = 0.8 to 0.9) to blood glucose and plasma insulin concentrations and also to the GDR (negative), while no such correlations were found with lipid uptake in subcutaneous or retroperitoneal abdominal adipose tissues. Taken together, these results suggest a higher turnover of lipids in visceral than in the other fat depots, which is closely correlated to systemic insulin resistance and glucose metabolism in men.
|
|
| 10. |
- Nylander, O, et al.
(författare)
-
Vasoactive intestinal polypeptide reduces hydrochloric acid-induced duodenal mucosal permeability.
- 1993
-
Ingår i: American Journal of Physiology. - 0002-9513 .- 2163-5773. ; 264:2 Pt 1, s. G272-9
-
Tidskriftsartikel (refereegranskat)abstract
- The duodenum in anesthetized rats was perfused with HCl, and mucosal integrity was assessed by measuring the clearance of 51Cr-labeled EDTA from blood to lumen and/or by morphological examination (lesion score). Duodenal blood flow was determined by laser Doppler flowmetry and luminal alkalinization as well as H+ disappearance by backtitration. Intravenous infusion of vasoactive intestinal polypeptide (VIP; 13.5 micrograms.kg-1.h-1) increased luminal alkalinization threefold and decreased clearance of 51Cr-EDTA by 50%. VIP also decreased arterial blood pressure and induced a small and irregular decrease in duodenal blood flow. Perfusion with 10 mM HCl increased clearance of 51Cr-EDTA 2.1-fold, but the lesion score was not different from that in saline-perfused animals. Perfusion with 20 mM HCl increased clearance of 51Cr-EDTA four-fold and induced a greater lesion score than did 10 mM. Perfusion with either 10 or 20 mM HCl did not affect the duodenal blood flow. VIP reduced the rise in clearance of 51Cr-EDTA in response to 10 mM but not that to 20 mM HCl. Intravenous injection of prazosin (50 micrograms/kg) decreased luminal alkalinization, clearance of 51Cr-EDTA, blood pressure, and duodenal blood flow. In prazosin-pretreated rats, perfusion with 10 mM HCl increased clearance of 51Cr-EDTA 2.6-fold, and the lesion score was greater in this group than in animals infused with VIP. A positive linear correlation was obtained between HCO3- secretion and the mean rate of H+ disappearance.(ABSTRACT TRUNCATED AT 250 WORDS)
|
|
