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C Trapp

Publications and source records attributed to C Trapp.

9 recordsLinked to original sources
PubMed2007

Deficiency of the Cockayne syndrome B (CSB) gene aggravates the genomic instability caused by endogenous oxidative DNA base damage in mice.

The Cockayne syndrome B protein (CSB) has long been known to be involved in the repair of DNA modifications that block the RNA polymerase in transcribed DNA sequences (transcription-coupled repair). Recent evidence suggests that it also has a more general role in the repair of oxidative DNA base modifications such as 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxoG). In mammalian cells, 8-oxoG is a substrate of the repair glycosylase OGG1. Mice without this enzyme accumulate 8-oxoG in the genome and have elevated spontaneous mutation rates. To elucidate the role of CSB in the prevention of mutations by oxidative DNA base damage, we have generated mice that are deficient in Csb or Ogg1 or both genes and carry a non-transcribed bacterial lacI gene for mutation analysis (Big Blue mice). Our results indicate that the overall spontaneous mutation frequencies in the livers of Csb(m/m)/Ogg1-/- -mice are elevated not only compared with heterozygous control mice (factor 3.3), but also with Ogg1-/- -animals (factor 1.6). Sequence analysis revealed that the additional mutations caused by CSB deficiency in an Ogg1-/- background are mostly G:C to T:A transversions and small deletions. For all mouse strains, the background levels of oxidative purine modifications in the livers correlate linearly with the numbers of G:C to T:A transversions observed. The data indicate that CSB is involved in the inhibition of mutations caused by spontaneous oxidative DNA base damage in a non-transcribed gene.

Animals↗
PubMed1993

Acquisition of manganous ions by mutans group streptococci.

The cariogenic bacteria Streptococcus sobrinus and S. cricetus were shown to have an absolute requirement for manganous ion in order to bind glucans or to adhere to glass in the presence of sucrose. The bacteria possessed a reasonably high affinity transport system for 54Mn2+, yielding a Km of about 12 microM. The Vmax for uptake of 54Mn2+ in S. sobrinus was increased when the bacteria were grown in Mn-depleted medium, but the Km remained the same. There was no evidence for two Mn2+ uptake systems, commonly observed for many bacteria. Ions such as Ca2+, Co2+, Co3+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+, Ni2+, and Zn2+ did not inhibit the uptake of 54Mn2+ by the bacteria, although Cd2+ was a potent inhibitor. Fractionation experiments showed that manganese was distributed in protoplasts (67%) and in the cell wall (33%). Approximately 80% of the 54Mn2+ in S. sobrinus was rapidly exchangeable with nonradioactive Mn2+. Electron spin resonance experiments showed that all of the manganese was bound or restricted in mobility. Proton motive force-dissipating agents increased the acquisition of 54Mn2+ by the streptococci, probably because the wall became more negatively charged when the cell could no longer produce protons.

Bacterial Adhesion↗
PubMed1983

Electron spin resonances of a living system (Drosophila) on normal and carcinogenic diets.

This investigation was a study of the free radical concentration of a living system, Drosophila melanogaster, by electron spin resonance spectroscopy. The paramagnetic content of the organism was measured as a function of age, mutant strain, and diet (normal vs. carcinogenic). In all cases, 4 to 6 days after ecdysis the free radical concentration decreased to approximately 70% of its value as measured shortly after ecdysis. The different mutant strains exhibited distinctly different free radical concentrations in accord with visual observations of the degree of pigmentation. Drosophila raised on a carcinogenic diet always showed a lower concentration of free radicals than the control groups on a normal diet.

Animals↗
PubMedDate not supplied

[Study of recovery and the post-anaesthetic period (author's transl)].

The authors compare recovery and the post-anaesthetic period in 45 patients anaesthetised with a combination of either pentothal, nitrous oxide, fluothane and dolosal (group 1, 24 subjects), or of pentothal, nitrous oxide and phenoperidine (group 2, 21 subjects). The quality of recovery was judged at the end of anaesthesia by determining of occurrence of the first response to 3 types of stimulation (calling the name, noise and pain) and the density of these responses during each minute. During the post-anaesthetic period the respective percentages of wakefulness and sleep were calculated. In this way the authors demonstrate a significant (P less than 0.01) shortening in recovery time for group 2, reactivity to own name occurring first in both groups, and a very significant (P less than 0.001) increase in the percentage of physiological sleep in subjects of group 2 during the post-anaesthetic stage.

Adolescent↗
PubMedDate not supplied

[Electroencephalographic features during enflurane anaesthesia in older children (author's transl)].

The authors report electroclinical changes observed during Enflurane anaesthesia, at various concentrations, in 25 children aged 4 to 14 years. EEG features are described from induction to surgical anesthesia (concentration 3-3.5%) and during overdoses (4-4.5%) with or without hyperventilation. Groups of spikes, low voltage sequences and electroclinical "seizures" (2 cases) only occur if the concentration of enflurane is not kept below 3.5%. A longitudinal study (24th hour, 3rd and 6th day) shows, by comparison with the pre-anaesthetic EEG, persistence in all cases of EEG slowing 24 hours after the anaesthesia, and in some patients EEG disturbances continue until the 6th day. These results are discussed in relation to data on the biodegradation of enflurane.

Adolescent↗
PubMedDate not supplied

[The E.E.G. of herpes encephalitis in children: 3 cases including one neonate (author's transl)].

The authors report 3 cases of herpes encephalitis in children aged respectively 15 days, 12 months and 18 months. In all 3 cases E.E.G. activity of a periodic nature was noted, which was continuous or intermittent, lateralised or focal in the temporal region, appearing from the 4th to 7th day. The periodicity (of the E.E.G. complex) was short and their stereotyped appearance particularly unusual in babies. In all 3 children convulsive seizures occurred before the discovery of the periodic activity. The latter was found to change in morphology and timing during the seizures. The disease process led to death of the neonate, and recovery with serious sequellae in the other two children. Possible relationships between the transitory nature of the periodic acitivity, the age and the eventual course of the disease, were discussed.

Electroencephalography↗
PubMedDate not supplied

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Computer Communication Networks↗