| 1. |
- Lundquist, Ingmar, et al.
(författare)
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Monoamines in pancreatic islets of guinea pig, hamster, rat, and mouse determined by high performance liquid chromatography
- 1989
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Ingår i: Pancreas. - 0885-3177. ; 4:6, s. 662-667
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies on the occurrence of catecholamines and serotonin in pancreatic islets using various histochemical and chemical methods have given widely different results. We therefore performed a comparative analysis of these amines in whole pancreas and islet tissue from hamster, guinea pig, rat, and mouse by the use of high performance liquid chromatography. Whole pancreas of guinea pig, hamster, and rat had a norepinephrine concentration of approximately 1.1 [mu]mol/kg of pancreatic wet weight. The mouse pancreas had less than one-half of that concentration. Epinephrine and dopamine concentrations were on the order of 0.02 [mu]mol/kg of pancreatic wet weight in all four species. The serotonin concentration was 2.1 [mu]mol/kg of pancreatic wet weight in the guinea pig pancreas and approximately 0.2 [mu]mol/kg in the other three species studied. The catecholamine concentrations were much higher in the pancreatic islets than in the exocrine pancreas. Thus, the norepinephrine concentration was approximately 35 [mu]mol/kg of islet wet weight in hamster islets and 5-10 [mu]mol/kg in rat, guinea pig, and mouse islets. The epinephrine concentration in islet tissue ranged between 1 and 7 [mu]mol/kg of islet wet weight and the dopamine concentration between 0.5 and 4 [mu]mol/kg except for guinea pig islets (12 [mu]mol/kg). The islet tissue in the mouse, rat, and guinea pig contained disproportionately more epinephrine and dopamine relative to norepinephrine than did the exocrine pancreas. Chemical sympathectomy (6- hydroxydopamine treatment) in the mouse reduced the norepinephrine and epinephrine concentrations in islet tissue to nondetectable levels, whereas the dopamine concentration was essentially unchanged, thus suggesting an extraneuronal source of this amine in addition to its occurrence in adrenergic nerves. The islets of hamster, rat, and mouse contained no serotonin, whereas guinea pig islets contained approximately 275 [mu]mol/kg of islet wet weight. We conclude that, although species differences exist, the pancreatic islets have markedly higher levels of catecholamines than the exocrine pancreas, and that serotonin occurs in the exocrine pancreas of all four species studied but in the endocrine pancreas only in the guinea pig.
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| 2. |
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| 3. |
- Lundborg, G, et al.
(författare)
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Intraneural edema following exposure to vibration
- 1987
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Ingår i: Scandinavian Journal of Work, Environment and Health. - 0355-3140. ; 13:4, s. 9-326
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral neuropathy represents a well-known complication from long-term exposure to vibration. In the present study an experimental model is presented with the purpose of analyzing the formation of intraneural edema following vibration exposure. Vibration (82 Hz, peak-to-peak amplitude 0.21 mm) was induced in the hind limb of rats by the use of vibrating electric motors during 4 h/d for 5 d. Tracer techniques (with albumin Evans blue and horseradish peroxidase) were used to study the permeability of intraneural microvessels after the vibration exposure on day 5. It was found that the vibration trauma in this model induced epineurial edema in the sciatic nerve. It is hypothesized that the formation of intraneural edema may be an important pathophysiological factor in the occurrence of vibration-induced neuropathy.
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| 4. |
- Bartosik, Jacek, et al.
(författare)
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Direct evidence for the cytomembrane derivation of Birbeck granules: the membrane-sandwich effect
- 1985
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Ingår i: Acta Dermato-Venereologica. - 1651-2057. ; 65:2, s. 157-160
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Tidskriftsartikel (refereegranskat)abstract
- Digitonin, which is known to cause extensive damage to cytomembranes in general, was found to have a most remarkable effect on epidermal Langerhans' cells. Thus, it generates a membrane-sandwiching process resulting in the formation of large discs which except for the differences in size have the same morphology as ordinary Birbeck granules. This demonstrates that the cytomembrane of the Langerhans' cell has the inherent ability to superimpose upon itself, leaving little doubt that the normal Birbeck granules derive from the cytomembrane.
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| 5. |
- Forslind, B., et al.
(författare)
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Elemental content of anagen hairs in a normal Caucasian population studies with proton induced X-ray emission (PIXE)
- 1986
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Ingår i: Scanning electron microscopy. - Chicago : IIT research institute. - 0586-5581. ; :Pt 1, s. 237-241
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Tidskriftsartikel (refereegranskat)abstract
- The elemental content of anagen hair fibers in a Caucasian population of healthy females and males in the age range 10-69 years was performed to constitute a baseline for further studies of pathological conditions. Proton induced X-ray emission (PIXE) analyses were performed on single hair fibers in triplicate from 103 individuals in order to determine sulfur, zinc, calcium, and chlorine content. The hair fibers were all anagen hairs collected from a site little influenced by genetic and hormonal influences 1.5 cm above the right ear of the probands. An area 5-8 mm from the follicle bottom was chosen for the analysis in all cases to minimize effect of hair-do contamination. The average sulfur content was 0.049 g/g and the average zinc content 170 micrograms/g. These results were not significantly influenced by chloroform/ethanol rinsing before analysis. The calcium and chlorine contents were 330 micrograms/g and 0.0033 g/g respectively. The latter data are expected to be more seriously influenced by external factors (e.g., contamination) than sulfur and zinc. No correlation between elemental concentration and sex was found for sulfur and zinc in the present material. PIXE analysis of single hair fibers yields valuable information on the elemental composition of hair fibers and can be rapidly and efficiently performed after simple mounting procedures.
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| 6. |
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| 7. |
- Hansson, Christer
(författare)
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Some indolic compounds as markers of the melanocyte activity
- 1988
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Ingår i: Acta dermato-venereologica. Supplementum. - 0365-8341. ; 138, s. 1-60
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Tidskriftsartikel (refereegranskat)abstract
- The melanocyte activity was studied by analysis of the urinary excretion of indolic and cysteinyldopa compounds. One eumelanin marker, 5,6-dihydroxy-indole-2-carboxylic acid was identified and quantified in normal urine. However, its low concentration and sensitivity to oxidation made it less suitable for clinical studies. A methylated derivative of this substance, 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI-2-C), was also demonstrated in normal urine. A quantitative method was worked out and the normal urinary concentration of this substance was as high as the concentration of 5-S-cysteinyldopa. The concentrations of the eumelanic marker 6-hydroxy-5-methoxyindole-2-carboxylic acid and the pheomelanic marker 5-S-cysteinyldopa were determined in the urine of psoriasis patients during PUVA treatment and also in the urine of subjects with different skin colour. The melanocyte activity in albinotic patients and in albinotic mice was studied by the same technique. Some in vitro experiments were performed to show that 5-S-glutathionyldopa has the molecular properties of forming a mercapto-substituted indole derivative. The following main conclusions were drawn: 1. 5,6-Dihydroxyindole-2-carboxylic acid and 6-hydroxy-5-methoxyindole-2-carboxylic acid are both present in measurable amounts in normal urine. 2. The urinary concentration of 6-hydroxy-5-methoxyindole-2-carboxylic acid increased during PUVA treatment in a similar way as for 5-S-cysteinyldopa. 3. The eumelanic marker 6-hydroxy-5-methoxyindole-2-carboxylic acid was excreted in larger quantities by people with genetically dark skin, whereas the pheomelanic marker 5-S-cysteinyldopa was not related to pigment type. 4. In the urine of one albino patient and in the urine of albinotic mice a total absence of 6-hydroxy-5-methoxyindole-2-carboxylic acid was found. The urinary concentrations of 5-S-cysteinyldopa in these subjects were measurable but lower than in pigmented subjects. Thus, 6-hydroxy-5-methoxy-indole-2-carboxylic acid seems to be a more specific melanocyte marker than the cysteinyldopas.
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| 8. |
- Jacobsson, B, et al.
(författare)
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Abnormality of adenylate cyclase regulation in human platelet membranes in renal insufficiency.
- 1985
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Ingår i: European journal of clinical investigation. - 0014-2972. ; 15:2, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- Adenylate cyclase in human platelets is under dual control of prostaglandins (PGI2 and PGE1) and catecholamines. The adenylate cyclase complex in membranes of platelets from ten patients with uraemia was investigated. The activation of the platelet cyclase by PGE1 is increased in the uraemic state, Vmax 4436 +/- 607 pmol cAMP mg-1 15 min-1. In the normal state Vmax is 2098 +/- 309 pmol cAMP mg-1 15 min-1. The alpha 2-adrenergic receptor was assayed with 3H-yohimbine binding. The density of receptors was equal in the uraemic (175 fmol mg-1 membrane protein) and the normal (170 fmol mg-1 membrane protein) states. Norepinephrine/3H-yohimbine competition binding revealed that catecholamines were bound with normal affinity in platelets in uraemia. Yet the inhibition of adenylate cyclase through the alpha 2-adrenergic receptor was diminished since Vmax values of adenylate cyclase with PGE1 and PGE2 + norepinephrine did not significantly differ. In the normal state, norepinephrine significantly (P less than 0.05) inhibited the PGE1 stimulated cyclase. It is concluded that platelet adenylate cyclase in the uraemia has an increased capacity for activation which is the result of both a sensitized stimulatory mechanism (prostaglandin mediated) and a deficient inhibitory mechanism (catecholamine mediated). It is suggested that a defect exists in the inhibitory nucleotide binding protein (NI) which is the coupling unit between the adenylate cyclase catalytic subunit (C).
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| 9. |
- Kagedal, Bertil, et al.
(författare)
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Automated high-performance liquid chromatographic determination of 5-S-cysteinyl-3,4-dihydroxyphenylalanine in urine
- 1989
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Ingår i: Journal of Chromatography A. - 0021-9673. ; 473, s. 359-370
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Tidskriftsartikel (refereegranskat)abstract
- An automated high-performance liquid chromatographic (HPLC) method has been developed for measurement of 5-S-cysteinyl-DOPA in urine (DOPA = 3,4-dihydroxyphenylalanine). The urinary sample was injected into an HPLC boronate column. With a mobile phase of 0.1 M phosphate buffer containing 0.2 mM disodium ethylenediaminetetraacetate (Na2EDTA) (pH 6.0) mixed with methanol (9:1), 5-S-cysteinyl-DOPA was adsorbed while most other compounds were washed away. By column switching, the column flow was reversed and 5-S-cysteinyl-DOPA was desorbed by a mobile phase of 0.1 M formic acid and 0.2 mM Na2EDTA at pH 3.0 and chromatographed on a reversed-phase column. The precision, as estimated from repeated analysis of an urinary sample and from duplicate analysis of a number of samples, ranged from 1.4 to 5.2% (coefficient of variation), and the analytical recovery was 93 +/- 4.1%. The method is suitable for use in the clinical laboratory.
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| 10. |
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