Biomedical subjects

T Svendsen

Publications and source records attributed to T Svendsen.

16 recordsLinked to original sources

PubMed1997

[Nicotine dependence among Norwegian smokers and possible consequences for preventive actions].

This article presents data on nicotine dependence among daily smokers in Norway in terms of Fagerströms Test for Nicotine Dependence (FTND). Nicotine dependence was higher among those smoking hand-rolled cigarettes than among those smoking manufactured cigarettes, in spite of the fact that the average number of cigarettes smoked per day was the same for both groups. The dependence also increased the lower the age of starting to smoke daily. Nicotine dependence was higher among daily smokers with a low level of education than among smokers with a higher level of education. This difference was explained by a difference in the proportion of respondents who smoked hand-rolled cigarettes in the two groups. The data are discussed in light of Norwegian research showing that hand-rolled cigarettes can contain two to three times as much nicotine and tar as manufactured cigarettes. When smokers of hand-rolled cigarettes are less motivated to quit they are exposed to greater health injury than smokers of manufactured cigarettes. The price of (and tax on) a hand-rolled cigarette is about half the price of a manufactured cigarette. Raising the tax on rolling tobacco would be very effective in promoting health and would have the particularly precise effect of reducing the differences in occurrence of disease and premature death among different social groups.

Adolescent↗

PubMed1997

Tobacco use among young adults in Norway, 1973-95: has the decrease levelled out?

OBJECTIVE: To describe the prevalence of tobacco use among young Norwegian adults, 1973-1995. DESIGN: Cross sectional personal and telephone surveys. SETTING: Norway, 1973-1995. PARTICIPANTS: Population based samples of Norwegians aged 16-74 years. RESULTS: A trend to a decline in tobacco use among young adult Norwegians during the 1960s and 1970s levelled out during the 1980s. Hence, the total prevalence of smoking in Norway decreased by only two percentage points from 1980 to 1993, as compared to approximately 10 percentage points in many other European countries. An increase in smoking prevalence (and in the use of snuff among males) in the age group 16-19 years has been observed in recent years. Thus smoking prevalence among young males and females in 1995 was comparable to that observed in the early 1980s. CONCLUSIONS: Trends in tobacco use reflect an underutilization of preventive measures in general, and health education measures in particular. Financial resources appropriated for health education and information were reduced by 90% during the 1980s.

Adolescent↗

PubMed1996

[Smoking habits and use of snuff in Norway 1973-95. Has the declining trend levelled off?].

A number of studies indicate that the prevalence of smoking declined among young Norwegian adults during the 1960s and 1970s. The present paper shows, however, that this decreasing trend seemed to level out during the 1980s. Hence the total prevalence of smoking in Norway decreased by only two percent units from 1980 to 1993, as compared with approximately 10% in many other European countries. Among persons aged 16-19 years an increased prevalence of smoking has been observed in most recent years. Consequently, in 1995 the smoking prevalences among young males and females were about the same as observed around 1980. These trends in smoking prevalence and use of snuff are discussed with particular reference to the lack of emphasis on preventive measures that has characterised the Norwegian tobacco policy during the last decades; especially that the funds allocated for tobacco-related health education and information were reduced by 90% during the 1980s.

Adolescent↗

PubMed1989

Energy is required for maximal adherence of Neisseria gonorrhoeae to phagocytic and nonphagocytic cells.

The possibility that gonococcal energy might play a role in the interaction of Neisseria gonorrhoeae with both phagocytic and nonphagocytic cells was examined. Respiratory chain inhibitors including KCN and amobarbital resulted in reduction in gonococcal association with human neutrophils. Similar results were seen with HeLa cells and the human promyelocytic (HL-60) cell line. Identical conditions did not affect the opsonin-dependent association of Staphylococcus aureus with the same cell types. New protein synthesis by gonococci did not account for the observed reduction in association. These results suggest that energy is needed for maximal opsonin-independent association of gonococci with mammalian cells.

Aerobiosis↗

PubMed1988

Phagocyte-derived lactate stimulates oxygen consumption by Neisseria gonorrhoeae. An unrecognized aspect of the oxygen metabolism of phagocytosis.

O2 consumption resulting from interaction of Neisseria gonorrhoeae and human neutrophils represents a composite of O2 consumed by the two cell systems. Experiments studying the relative contribution of each system suggested the possibility that gonococci increased their metabolic activity in response to interaction with neutrophils. This hypothesis was confirmed by demonstrating that undifferentiated HL-60 cells, which are unable to undergo a respiratory burst, induce a two- to three-fold increase in gonococcal O2 consumption. Gonococcal capacity to adhere to HL-60 cells did not correlate with extent of metabolic stimulation. Stimulatory activity was demonstrable in cell-free supernatant from neutrophils or HL-60 cells, and increased with duration of incubation. Supernatant applied to a G-15 Sephadex column yielded fractions that stimulated gonococcal O2 consumption. Elution profiles were similar for HL-60 cells, neutrophils, and a stimulatory factor previously isolated from pooled human serum. This stimulatory factor(s) failed to adhere to DEAE or C-18 HPLC columns. Stimulatory activity release from myeloid cells was inhibited by incubation at 4 degrees C or in the presence of NaF, indicating a critical role for glucose metabolism. Lactate, the principal product of resting neutrophil glucose catabolism, was demonstrable in cell-free supernatants after incubation at 37 degrees C. Lactate accumulation was inhibited by NaF and decreased temperature of incubation. Lactate at levels present in cell-free supernatant increased gonococcal O2 consumption twofold and restored stimulatory activity to dialyzed serum. Live, but not heat-killed gonococci eliminated lactate released from neutrophils during phagocytosis. Gonococci are able to utilize host-derived lactate to enhance their rate of O2 metabolism.

Cell Line↗

PubMed1987

Bacteria form intracellular free radicals in response to paraquat and streptonigrin. Demonstration of the potency of hydroxyl radical.

The generation of oxygen reduction products by Neisseria gonorrhoeae FA1090 upon exposure to streptonigrin (SNG) and paraquat (PQ2+) and their toxicity was examined. N. gonorrhoeae exhibited maximal cyanide-insensitive respiration, which was employed as an indicator of superoxide (O2-) formation, in the presence of 0.064 mM streptonigrin and 90 mM PQ2+, respectively. Using the concentrations of SNG and PQ2+ described above, complete lethality (greater than 10(8) cells/ml) was observed among cells exposed to SNG, whereas PQ2+ reduced viability by only 3 logs. In an attempt to determine the oxygen radical species generated by gonococci when exposed to SNG, dimethyl sulfoxide, Fe3+, KCN, and the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), we were able to detect .OH manifested as the methyl adduct (DMPO-CH3). The production of the latter species was not inhibited by catalase, suggesting intracellular .OH generation. When PQ2+ was substituted for SNG, only low levels of DMPO-CH3 were observed, the production of which ceased within 8 min. SNG and PQ2+, added to a O2(-)- generating system in the presence of Fe3+, promoted increased .OH generation. The iron chelator diethyl-enetriaminepentaacetic acid enhanced the generation of spin-trapped .OH and O2- in the presence of PQ2+. The addition of catalase to this system, however, eliminated the DMPO-CH3 signal, showing that the .OH in this system was extracellular. PQ2+-mediated generation of extracellular .OH in the presence of Fe3+-diethylenetriaminepentaacetic acid EDTA did not enhance the killing of gonococci by PQ2+. These data show that the lethality of SNG relative to PQ2+ is due to the inherent ability of SNG to catalyze the formation of critical levels of intracellular .OH, detectable through the use of spin trapping techniques.

Cyanides↗

PubMed1987

Role of extracellular iron in the action of the quinone antibiotic streptonigrin: mechanisms of killing and resistance of Neisseria gonorrhoeae.

The quinone antibiotic streptonigrin is believed to kill bacteria by promoting formation of oxygen radicals. This antibiotic has also been used to select resistant bacterial mutants, some of which vary in iron utilization. We examined the effects of streptonigrin on Neisseria gonorrhoeae and several types of gonococcal mutants. Streptonigrin (0.025 microgram/ml) efficiently killed gonococcal strain FA1090, and this effect depended on iron. Streptonigrin-resistant mutant FA6271 had normal iron uptake but was moderately deficient in total iron. Resistance most likely resulted from failure of FA6271 to divert electrons to streptonigrin, as demonstrated by a reduction in KCN-insensitive respiration (a hallmark of the action of quinones) and superoxide formation. Other mutants selected for inability to use human iron-binding proteins (strains FA6273 and FA6275) had no increase in streptonigrin MIC and no decrease in KCN-insensitive respiration. Mutants did not demonstrate an increase in superoxide dismutase or catalase. Streptonigrin killing of gonococci depended on a reaction(s) in which extracellular iron was important, presumably because iron was required for catalysis of hydroxyl radical. The results suggest that a membrane component may be a target for the actions of streptonigrin.

Catalase↗

PubMed1984