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1
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Inhibitory effects of pentamidine analogues on protein biosynthesis in vitro.

100%
Bielawski K., Galicka A., Bielawska A., Średzińska K.
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2000
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vol. 47
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issue 1
113-120
EN
Pentamidine despite its rather high toxicity, is currently in clinical use. For development of new drugs of this type it is important to know the mechanism of their action. Two new amidines (I and II) and 4',6-diamidino-2-phenylindole (DAPI) were found in preliminary experiments to inhibit protein synthesis in vitro in the cell-free rat liver system. The three compounds differed in the precise mode of action. The inhibitory effect of I on the activity of the eukaryotic elongation factor eEF-2 and ribosomes seems to suggest that the binding site of eEF-2 on the ribosome was blocked by this compound. eEF-2 has been identified as the primary target of II and eEF-1 as the primary target of DAPI in the system studied.
2
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Effect of cadmium on collagen content and solubility in rat bone.

100%
Galicka A., Brzóska M. M., Średzińska K., Gindzienski A.
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vol. 51
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issue 3
825-829
EN
The toxic action of cadmium in the bone tissue is known, but its mechanisms are still unexplained. We examined whether Cd influences collagen content and its solubility in the femoral bone of three-week-old female rats exposed to 5 or 50 mg Cd/l in drinking water. Non-cross linked collagen was extracted with 0.5 M acetic acid, and two acid-insoluble collagen fractions were extracted with pepsin and 4.0 M guanidine hydrochloride, respectively. SDS/PAGE showed the presence of two collagen types, I and V, in all three extracted fractions. Exposure of rats to Cd for 6 months increased the amount of acid-soluble collagens type I and V and decreased the level of acid-insoluble collagens. The amount of total collagen extracted from the bones of rats exposed to 50 mg Cd/l was reduced by about 14% as compared to control and those intoxicated with 5 mg Cd/l. The solubility of type I bone collagen (determined as the percentage of acetic-soluble fraction of total collagen) was increased 2.9- and 3.0-fold in rats intoxicated with 5 and 50 mg Cd/l, respectively. Similarly, the solubility of type V collagen was increased 2.3- and 2.7-fold, respectively. Our results indicate that Cd treatment affects bone collagen by decreasing its content and increasing its solubility.
3
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Studies on type I collagen in skin fibroblasts cultured from twins with lethal osteogenesis imperfecta.

100%
Galicka A., Wołczyński S., Gindzieński A.
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2003
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vol. 50
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issue 2
481-488
EN
Studies on type I procollagen produced by skin fibroblasts cultured from twins with lethal type II of osteogenesis imperfecta (OI) showed that biosynthesis of collagen (measured by L-[5-3H]proline incorporation into proteins susceptible to the action of bacterial collagenase) was slightly increased as compared to the control healthy infant. SDS/PAGE showed that the fibroblasts synthesized and secreted only normal type I procollagen. Electrophoretic analysis of collagen chains and CNBr peptides showed the same pattern of electrophoretic migration as in the controls. The lack of posttranslational overmodification of the collagen molecule suggested a molecular defect near the amino terminus of the collagen helix. Digestion of OI type I collagen with trypsin at 30°C for 5 min generated a shorter than normal α2 chain which melted at 36°C. Direct sequencing of an asymmetric PCR product revealed a heterozygous single nucleotide change C→G causing a substitution of histidine by aspartic acid in the α2 chain at position 92. Pericellular processing of type I procollagen by the twin's fibroblasts yielded a later appearance of the intermediate pC-α1(I) form as compared with control cells.
4
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A novel Gly to Arg substitution at position 388 of the α1 chain of type I collagen in lethal form of osteogenesis imperfecta.

88%
Galicka A., Wolczynski S., Lesniewicz R., Chyczewski L., Gindzienski A.
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2002
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vol. 49
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issue 2
443-450
EN
Cultured skin fibroblasts from a proband with a lethal form of osteogenesis imperfecta produce two forms of type I collagen chains, with normal and delayed electrophoretic migration; collagen of the proband's mother was normal. Peptide mapping experiments localized the structural defect in the proband to α1(I) CB8 peptide in which residues 123 to 402 are spaned. Direct sequencing of amplified cDNA covering this region revealed a G to A single base change in one allele of the α1(I) chain, that converted glycine 388 to arginine. Restriction enzyme digestion of the RT-PCR product was consistent with a heterozygous COL1A1 mutation. The novel mutation conforms to the linear gradient of clinical severity for the α1(I) chain and results in reduced thermal stability by 3°C and intracellular retention of abnormal molecules.
5
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Glutathione reductase activity correlates with concentration of extracellular matrix degradation products in synovial fluid from patients with joint diseases

76%
Średzińska K., Galicka A., Porowska H., Średziński Ł., Porowski T., Popko J.
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issue 4
635-640
EN
The mechanisms underlying cartilage matrix degradation in joint diseases is not fully understood but reactive oxygen species are implicated as main causative factors. Comparative studies of glutathione reductase (GR) activity in synovial fluid from patients with rheumatoid arthritis (RA), reactive arthritis (ReA) and osteoarthritis (OA) as well as correlations between GR activity and concentration of the major cartilage components in synovial fluid are presented in this study. We found significantly higher activity of GR in RA (about three-fold) and ReA (about two-fold) than in OA. In RA and ReA patients, GR activity in synovial fluid correlates negatively with the concentrations of collagen and degradation products of sulfated glycosaminoglycans. In OA patients the activity of GR was significantly lower than in RA and ReA, which positively correlated with the concentration of collagen and showed a tendency for positive correlation with the degradation products of sulfated glycosaminoglycans. Our results suggest that in RA and ReA patients increased activity of GR does not prevent the increased degradation of collagen and proteoglycans by ROS.
6
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Mutations in the COL1A1 and COL1A2 genes associated with osteogenesis imperfecta (OI) types I or III

64%
Augusciak-Duma A., Witecka J., Sieron A., Janeczko M., Pietrzyk J., Ochman K., Galicka A., Borszewska-Kornacka M., Pilch J., Jakubowska-Pietkiewicz E.
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2018
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vol. 65
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issue 1
79-86
EN
Although over 85% of osteogenesis imperfecta (OI) cases are associated with mutations in the procollagen type I genes (COL1A1 or COL1A2), no hot spots for the mutations were associated with particular clinical phenotypes. Eight patients that were studied here, diagnosed with OI by clinical standards, are from the Polish population with no ethnic background indicated. Previously unpublished mutations were found in six out of those eight patients. Genotypes for polymorphisms (Sp1 - rs1800012 and PvuII - rs412777), linked to bone formation and metabolism were determined. Mutations were found in exons 2, 22, 50 and in introns 13 and 51 of the COL1A1 gene. In COL1A2, one mutation was identified in exon 22. Deletion type mutations in COL1A1 that resulted in OI type I had no effect on collagen type I secretion, nor on its intracellular accumulation. Also, a single base substitution in I13 (c.904-9 G>T) was associated with the OI type I. The OI type III was associated with a single base change in I51 of COL1A1, possibly causing an exon skipping. Also, a missense mutation in COL1A2 changing Gly→Cys in the central part of the triple helical domain of the collagen type I molecule caused OI type III. It affected secretion of the heterotrimeric form of procollagen type I. However, no intracellular accumulation of procollagen chains could be detected. Mutation in COL1A2 affected its incorporation into procollagen type I. The results obtained shall help in genetic counseling of OI patients and provide a rational support for making informed, life important decisions by them and their families.
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