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1.

001-es BibID:BIBFORM053853
Első szerző:Sanden, Monique J. T. van Der
Cím:An in vitro model of aging : the influence of increasing physical density on enzyme activities of trypsin, xanthine oxidase and superoxide dismutase / Monique J. T. van Der Sanden, Katalin Nagy, Imre Semsei, Imre Zs.-Nagy
Dátum:1995
ISSN:0167-4943
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology and Geriatrics. - 20 : 3 (1995), p. 273-282. -
További szerzők:Nagy Katalin Semsei Imre (1954-) (vegyész, gerontológus) Zs. Nagy Imre
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2.

001-es BibID:BIBFORM053848
Első szerző:Semsei Imre (vegyész, gerontológus)
Cím:In vitro studies on the OH* and O2-* free radical scavenger properties of idebenone in chemical systems / I. Semsei, K. Nagy, I. Zs.-Nagy
Dátum:1990
ISSN:0167-4943
Megjegyzések:OH(*) free radicals were generated by Fenton reaction in the presence of bovine serum albumin (BSA). The decreasing water-solubility of BSA with increasing Fe(2+) concentrations of the system is a sensitive indicator of the cross-linking effects of the OH(*) free radicals. Idebenone (oxidized form) was solubilized for this experiment in DMSO and added to the system in final concentrations of 0.01 or 0.1%. Neither of these concentrations displayed any protective effect against the insolubilization of BSA. Therefore, oxidized idebenone has to be considered as a substance which reacts with OH(*) free radicals slower than the BSA itself, i.e., its oxidized form is not an efficient scavenger of this type of free radicals under the given circumstances. The ability of idebenone to scavenge superoxide radicals was tested in ( [Formula: see text] ) the pyrogallol system; and (ii) the xanthine-xanthine oxidase-nitro blue tetrazolium (XXO-NBT) system. Idebenone did not show any O(2)(-*) radical scavenging ability as revealed by these two in vitro methods, in the concentration ranges studied (up to 75 or 220 microg/ml, respectively). On the contrary, an increasing O(2)(-*) radical generation was observed with increasing concentrations of the drug in both test systems used. The possible biological significance of these observations is discussed in the light of other results like ESR spin trapping and measurements of superoxide dismutase (SOD) activity in various tissues.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology snd Geriatrics. - 11 : 3 (1990), p. 187-197. -
További szerzők:Nagy Katalin Zs. Nagy Imre
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3.

001-es BibID:BIBFORM053847
Első szerző:Semsei Imre (vegyész, gerontológus)
Cím:The effects of idebenone on DNA and RNA contents as well as synthesis rates of total and poly(A)+ RNA in brain of normal, old C57BL/6J mice and in experimental partial cerebral ischemia of rats / I. Semsei, R. G. Cutler, I. Zs.-Nagy
Dátum:1990
ISSN:0167-4943
Megjegyzések:Effects of idebenone on RNA and DNA contents as well as on synthesis rates of total and poly(A)(+) RNA in the brain were measured in two animal models: (1) Normal young and old, male C57BL/6J mice (6 and 32 months). Idebenone suspended in 5% gum arabic was applied in 50 mg/kg/day dose to old mice for 1 month through a gastric tube. (2) Adult female CFY rats (14-18 months) in which experimental partial cerebral ischemia was induced by bilateral common carotid artery occlusion. Idebenone was administered intraperitoneally in two dose (10mg/kg and 100 mg/kg body weight) 30 min before the interruption of carotid blood flow. DNA content remained invariate during aging in the brain; idebenone treatment did not exert any influence on this parameter. RNA content as well as total and poly(A)(+) RNA synthesis rates, which were measured by incorporation of tritiated uridine into RNA, decreased significantly with age in brain. Idebenone treatment did not cause any essential change of the metabolism of RNA under the given conditions. The RNA and DNA contents of brain were influenced neither by experimental partial cerebral ischemia nor by treatment with idebenone during the ischemia. Partial cerebral ischemia decreased the rate of total and poly(A)(+) RNA synthesis in the brain about 15-45% depending on the methods and basis of expression. This decline could totally be prevented by intraperitoneal application of 10 mg/kg idebenone 30 min before the onset of the partial ischemia. The dose of 100 mg/kg idebenone also elevated the rate of RNA synthesis; however, this increase remained statistically insignificant.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology And Geriatrics. - 11 : 3 (1990), p. 293-306. -
További szerzők:Cutler, Richard G. Zs. Nagy Imre
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4.

001-es BibID:BIBFORM053843
Első szerző:Semsei Imre (vegyész, gerontológus)
Cím:Effects of ionic strength on the activity of superoxide dismutase in vitro / I. Semsei, I. Zs.-Nagy
Dátum:1984
ISSN:0167-4943
Megjegyzések:Changes in superoxide dismutase (SOD) activity were studied in vitro at increasing NaCl or KCl concentrations. SOD activity was measured using two different systems of superoxide radical generation: pyrogallol autoxidation, and xanthine-xanthine oxidase reaction. Pyrogallol autoxidation was directly measured by spectrophotometry, whereas in the second case cytochrome c reduction was followed at 550 nm. The inhibition of SOD on those parameters was taken as measure of SOD activity. Increasing concentrations of NaCl and KCI significantly increased the rate of pyrogallol autoxidation. The inhibitory effect of SOD significantly decreased under the influence of these salts and followed an exponential curve. The two salts studied resulted in essentially identical changes in SOD activity. Increasing concentrations of NaCl and KCl decreased the rate of cytochrome c reduction in the xanthine-xanthine oxidase system. When correcting the results for these primary effects, SOD activity also displayed in this system an exponential decay with increasing salt concentrations. The results are interpreted in terms of the known charge distribution pattern on the surface of the SOD molecule, and of the age-dependent increase of the intracellular potassium and sodium concentrations in the postmitotic cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology and Geriatrics. - 3 : 4 (1984), p. 287-295. -
További szerzők:Zs. Nagy Imre
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5.

001-es BibID:BIBFORM053841
Első szerző:Semsei Imre (vegyész, gerontológus)
Cím:In vivo stimulation of nerve cells by phytohemagglutinin : II. Alterations in the rate of total and mRNA synthesis in the brain cortex of old rats / I. Semsei, I. Zs.-Nagy
Dátum:1983
ISSN:0167-4943
Megjegyzések:Bacto-phytohemagglutinin-P (PHA-P) was administered in form of a single intralumbar injection of 2 mg/100 g body weight dose to 24- to 28-mth-old female CGY rats. The accuracy of the injection technique was checked by adding 2% lidocaine to the injection mixture, which resulted in a transient and symmetric paralysis of the posterior limbs when reaching the cerebrospinal fluid. The total RNA content of the liver and brain cortex were measured, and phenolic extraction of RNA was performed the brain cortex. Poly(A) +RNA (mRNA) was separated from the total RNA of the brain cortex by oligo(dT)-cellulose chromatography. Pulse labeling with tritiated uridine was performed 45 min before killing the animals and the incorporation of the radiolabel was measured in the respective RNA classes and corrected for the nucleotide pool size. The rates of total and mRNA synthesis are expressed in percentages of the young untreated rats and compared to old untreated animals. The effects of PHA-P was studied at 4, 10, 20 and 44 h after its injection. A considerable increase of the total RNA content of the brain cortex was measured during the first 10 h of the experiment followed by a slow decrease. However, the RNA content of the brain cortex was still significantly higher at the end of experiment compared to untreated old rats. The rate of total RNA synthesis increased significantly during the first 10 h and remained constantly high until 44 h. The rate of mRNA synthesis increased to a higher extent than that of the total RNA, and also remained high until 44 h.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology and Geriatrics. - 2 : 4 (1983), p. 307-316. -
További szerzők:Zs. Nagy Imre
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6.

001-es BibID:BIBFORM053840
Első szerző:Semsei Imre (vegyész, gerontológus)
Cím:In vivo studies on the age-dependent decrease of the rates of total and mRNA synthesis in the brain cortex of rats / I. Semsei, F. Szeszák, I. Zs.-Nagy
Dátum:1982
ISSN:0167-4943
Megjegyzések:The membrane hypothesis of aging (Zs.-Nagy, I., 1978, J. Theor. Biol. 75, 189-195) attributes the primary role in cellular aging to an age-dependent decrease of the passive potassium permeability of the cell membrane which is due most probably to free-radical damage of the membrane components. As a consequence, the intracellular and intranuclear ionic strength increases resulting in a condensation of the chromatin and a slowing down of the synthetic processes performed by the nucleus. In this concept it was of importance to reveal whether the rates of total and mRNA synthesis display any age-dependent alteration parallel with the change of membrane permeability of the brain nerve cells. Experiments were performed using tritiated uridine incorporation measurements and suitable preparation techniques in young, adult and old rats (1.5, 13 and 25 mth of age, respectively). Comparisons of the incorporation rates revealed a very considerable decrease in the rate of synthesis of both the total and polyadenylated RNA (polyA + RNA) between the ages of 13 and 26 mth. The old animals displayed only about 55 and 67% of the rate of synthesis for the 2 classes of RNA, respectively, as compared to the young and adult rats, if the results are expressed as dpm/mg RNA. However, the decreases are even more pronounced (34 and 41%) if the results are expressed on a dry weight basis. The results obtained are compatible with the membrane hypothesis of aging.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology and Geriatrics. - 1 : 1 (1982), p. 29-42. -
További szerzők:Szeszák Ferenc Zs. Nagy Imre
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7.

001-es BibID:BIBFORM053851
Első szerző:Semsei Imre (vegyész, gerontológus)
Cím:Effect of age on the activity of ceruloplasmin of human blood / I. Semsei, F. Jeney, T. Fülöp
Dátum:1993
ISSN:0167-4943
Megjegyzések:Aminoxidase activity of ceruloplasmin was measured in the serum of 120 people (between 45 and 102 years of age) using the p-phenylenediamine method. A negative linear age-correlation (-30% for the whole lifespan; P < 0.01) was established in this activity with increasing age, nevertheless the total copper content of blood did not change in the same age-range as measured by an atomic absorption spectrophotometric method. Increasing ionic strength, in vitro, caused an exponential decline in blood ceruloplasmin aminoxidase activity of both middle aged and elderly subjects. The age-dependent decrease in ceruloplasmin activity could have a negative effect on the antioxidant functions of blood, and finally on the aging process itself.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Archives of Gerontology and Geriatrics. - 17 : 2 (1993), p. 123-130. -
További szerzők:Jeney Florence Fülöp Tamás (1928-) (népegészségügyi szakember, egészségfejlesztő)
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