| 31. |
- Berggren Söderlund, Maria, et al.
(författare)
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Concentrations of retinoids in early pregnancy and in newborns and their mothers.
- 2005
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Ingår i: American Journal of Clinical Nutrition. - 1938-3207. ; 81:3, s. 633-636
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Tidskriftsartikel (refereegranskat)abstract
- Background: Retinoids are vital for embryonic development; both excesses and deficiencies of vitamin A are known to give similar patterns of birth defects. Concentrations of retinol in newborns and in pregnant women have been investigated, but concentrations of the biologically active metabolite all-trans retinoic acid and its isomer 13-cis retinoic acid have not. Objective: We measured serum concentrations of these retinoid derivatives in newborns and their mothers and in women in the first trimester of pregnancy, when embryonic differentiation (organogenesis) takes place. Design: In this descriptive study, 10 newborns from normal deliveries and their mothers and 16 healthy women in their first trimester of pregnancy were studied. Seventeen healthy women served as control subjects. all-trans and 13-cis Retinoic acid and retinol concentrations were measured by HPLC. Results: The newborns had significantly lower retinol concentrations (1.0 mu mol/L) than did their mothers (1.7 mu mol/L; P = 0.013). Serum all-trans retinoic acid was also significantly lower in the newborns (3.4 nmol/L) than in their mothers (5.8 nmol/L; P = 0.008). In addition, serum concentrations of 13-cis retinoic acid were significantly lower in the newborns (2.0 nmol/L) than in their mothers (2.6 nmol/L; P = 0.005). The serum concentrations of all-trans retinoic acid and retinol did not correlate in any group. Conclusion: Retinol concentrations do not accurately reflect the concentrations of the biologically active derivative all-trans retinoic acid.
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| 32. |
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| 33. |
- Bitzén, Ulrika, et al.
(författare)
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Retinyl palmitate is a reproducible marker for chylomicron elimination from blood
- 1994
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 54:8, s. 611-613
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Tidskriftsartikel (refereegranskat)abstract
- To study the individual variation in chylomicron clearance rate, young healthy volunteers were given a p.o. dose of 50,000 IU retinyl palmitate in the morning to label their chylomicrons. Serial blood samples were then obtained in the time interval 4-8 h after retinyl palmitate intake, to closely monitor the clearance of retinyl ester from the blood. The procedure was repeated in an identical way two days later. The calculated individual halflives for retinyl palmitate clearance ranged from 1.54 to 9.90 h, i.e. a more than five-fold variation. The intraindividual variation was much less (relative SD 11%). Retinyl palmitate clearance (and probably chylomicron clearance) is, thus, relatively constant within the same individual on different occasions but varies considerably between individuals.
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| 34. |
- Boren, Jan, et al.
(författare)
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The molecular mechanism for the genetic disorder familial defective apolipoprotein B100
- 2001
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:12, s. 9214-9218
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Tidskriftsartikel (refereegranskat)abstract
- Familial defective apolipoprotein B100 (FDB) is a genetic disorder in which low density lipoproteins (LDL) bind defectively to the LDL receptor, resulting in hypercholesterolemia and premature atherosclerosis. FDB is caused by a mutation (R3500Q) that changes the conformation of apolipoprotein (apo) B100 near the receptor-binding site. We previously showed that arginine, not simply a positive charge, at residue 3500 is essential for normal receptor binding and that the carboxyl terminus of apoB100 is necessary for mutations affecting arginine 3500 to disrupt LDL receptor binding. Thus, normal receptor binding involves an interaction between arginine 3500 and tryptophan 4369 in the carboxyl tail of apoB100. W4369Y LDL and R3500Q LDL isolated from transgenic mice had identically defective LDL binding and a higher affinity for the monoclonal antibody MB47, which has an epitope flanking residue 3500. We conclude that arginine 3500 interacts with tryptophan 4369 and facilitates the conformation of apoB100 required for normal receptor binding of LDL. From our findings, we developed a model that explains how the carboxyl terminus of apoB100 interacts with the backbone of apoB100 that enwraps the LDL particle. Our model also explains how all known ligand-defective mutations in apoB100, including a newly discovered R3480W mutation in apoB100, cause defective receptor binding.
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| 35. |
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| 36. |
- Di, Dongmei, et al.
(författare)
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ABCA1 upregulating apolipoproein M expression mediates via the RXR/LXR pathway in HepG2 cells
- 2012
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 421:1, s. 152-156
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Tidskriftsartikel (refereegranskat)abstract
- We have previously reported that liver X receptor (LXR) agonist, TO901317, could significantly inhibit hepatic apolipoprotein M (apoM) expression. It has been reported that TO901317 could activate the ATP-binding cassette transporter A1 (ABCA1) that mediates cholesterol efflux to the lipid-poor apoA1, which is an essential step for the high-density lipoprotein (HDL) formation. It is unknown if ABCA1 may regulate hepatic apoM expression. In the present study, HepG2 cells were cultured with the synthetic LXR agonists, TO901317 or GW3965 in the presence or absence of ABCA1 antagonist, disodium 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS). The mRNA levels of ABCA1, apoM and liver receptor homolog-1 (LRH-1) determined by the real-time RT-PCR. It demonstrated that both TO901317 and GW3965 could significantly enhance ABCA1 expression, and simultaneously, inhibit LRH1 expression. However, TO901317 alone could significantly inhibit apoM expression, while GW3965 alone did not influence apoM expression. ABCA1 antagonist, DIDS, have no effects on GW3965 induced upregulation of ABCA1 and downregulation of LRH1. However, apoM mRNA level was significantly decreased when the cells cultured with GW3965 together with DIDS. The present study demonstrated that apoM expression could be elevated by ABCA1 via the RXR/LXR pathway and LRH1 does not involve in the regulation of apoM by the activation of ABCA1, although the direct regulative pathway(s) between ABCA1 and apoM gene is still unknown yet. The detailed mechanism needs further investigation. (C) 2012 Elsevier Inc. All rights reserved.
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| 37. |
- Ekbom, Tord, et al.
(författare)
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Decrease in high density lipoprotein cholesterol during prolonged storage. CELL Study Group
- 1996
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 56:2, s. 97-101
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Tidskriftsartikel (refereegranskat)abstract
- Different studies on the stability of high density lipoprotein cholesterol (HDL) in frozen serum or plasma have yielded conflicting results, namely increase, decrease, or no change at all during prolonged storage under freezing conditions. As part of a major trial on lipid-lowering strategies we statistically demonstrated a time-related decrease in HDL cholesterol during storage up to 46 months at -20 degrees C. We therefore re-analysed 85 frozen samples that had been analysed fresh and then stored from 26 to 46 months, using the dextran sulphate 500/Mg2+ method. A linear regression analysis of change in HDL cholesterol on time was performed. The slope was significantly negative (p < 0.0005). The regression equation was (decrease in HDL) = 0.05 - 0.008 x (time in months), i.e. after 6 months' storage at -20 degrees C there was almost a 1% decrease in the HDL cholesterol concentration per month of storage.
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| 38. |
- Ekelund, Mats, et al.
(författare)
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Effects of total parenteral nutrition on lipid metabolism in rats
- 1994
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Ingår i: JPEN. - : Wiley. - 0148-6071. ; 18:6, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The pathophysiologic mechanisms behind the development of liver steatosis during total parenteral nutrition (TPN) and the possible relationship to alterations of lipoprotein lipase activities in different tissues are not fully known. It is also unknown whether continuous and discontinuous administration of TPN affect lipid metabolism differently. METHODS: TPN, including 8.4 g of triglycerides per kilogram per day, was given for 10 days to two groups of male Sprague-Dawley rats that received the infusions discontinuously and continuously, respectively. Freely fed rats were used as controls. RESULTS: TPN led to hyperlipidemia and accumulation of triglycerides in the liver. High-density lipoproteins were enriched in triglycerides, whereas high-density lipoprotein cholesterol and phospholipid levels were low. The activities of hepatic lipase were markedly decreased, and lipoprotein lipase activities in adipose tissue and in cardiac muscle were both up-regulated. The increased levels of cholesterol and phospholipids in the serum of TPN animals were more pronounced after discontinuous administration. CONCLUSIONS: TPN including lipids interferes with the normal regulation of lipid metabolism. Although the mechanisms remain obscure, the elevation of lipoprotein lipase activities seems functionally important to accommodate the increased input of triglycerides during TPN. Possibly, the observed alterations in lipase activities may be attributed to a state of hypothyroidism.
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| 39. |
- Ekström, Ulf, et al.
(författare)
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A Swedish family with a mutation in the peripherin/RDS gene (Arg-172-Trp) associated with a progressive retinal degeneration
- 1998
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Ingår i: Ophthalmic Genetics. - : Swets & Zeitlinger Publishers. - 1744-5094 .- 1381-6810. ; 19:3, s. 149-156
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To clinically characterize a Swedish family with autosomal dominant retinitis pigmentosa due to a mutation, Arg-172-Trp, in the peripherin/RDS gene. METHODS: Full clinical evaluation including kinetic visual field testing, measurement of dark-adaptation threshold, and full-field electroretinography in seven patients with autosomal dominant retinitis pigmentosa and three healthy family members. Denaturing gradient gel electrophoresis (DGGE) was used for mutation screening in seven patients and six healthy members of the family. RESULTS: Three of four siblings from the middle generation and four of the younger generation were heterozygous for the peripherin /RDS Arg-172-Trp mutation. The mutation segregated with the disease. Visual acuity decreased progressively with age and visual fields were moderately constricted in young patients, while central scotoma and constriction of the fields were detected in the family members above 50 years of age. The results from full-field electrography were comparable with a widespread retinal degeneration. CONCLUSIONS: Earlier, the peripherin/RDS Arg-172-Trp mutation was associated primarily with a macular degeneration phenotype. One previous study indicated that this mutation also can give rise to a degeneration of the more peripheral parts of the retina. In the present study, a widespread retinal degeneration is seen in the patients above 50 years of age, carrying the Arg-172-Trp mutation.
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| 40. |
- Ekström, Ulf, et al.
(författare)
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An efficient screening procedure detecting six novel mutations in the LDL receptor gene in Swedish children with hypercholesterolemia
- 1995
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Ingår i: Human Genetics. - 1432-1203. ; 96:2, s. 147-150
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Tidskriftsartikel (refereegranskat)abstract
- Familial hypercholesterolemia (FH) is an autosomal semi-dominant disorder caused by defects in the low density lipoprotein receptor (LDLR) gene and is a well-documented risk factor for developing cardiovascular disease. The LDLR genes of five Swedish children with FH were examined in this study. Initial mutation screening was performed by denaturing gradient gel electrophoresis (DGGE) with enzymatically amplified exon-sized fragments, each containing a tailing GC-rich requence. The GC-clamped fragments had been synthesized with a restriction site adjacent to the intron-corresponding sequence to allow detachment of the clamps, thereby rendering the fragments suitable for subsequent analysis by single-strand conformation polymorphism (SSCP) analysis of samples from patients with no DGGE-detectable mutations. In addition, all the LDLR genes of the patients were screened for large alterations by restriction fragment length polymorphism analysis. Following this strategy, seven different, potentially disease-causing mutations were detected in the five children with FH. Six of the alterations, five single-base substitutions and one dinucleotide deletion, have not previously been described. DGGE detected six of the mutations and SSCP the seventh.
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