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Biomedical subjects

H de Vries

Publications and source records attributed to H de Vries.

At least 127 records · Page 7Linked to original sources
PubMed1976

The mitochondrial ribosomes of Neurospora crassa. II. Comparison of the proteins from Neurospora crassa mitochondrial ribosomes with ribosomal proteins from Neurospora cytoplasm, from rat liver mitochondria and from bacteria.

1. It has been shown by Datema et al. (Datema, R., Agsteribbe, E. and Kroon, A.M. (1974) Biochim. Biophys. Acta 335, 386--395) that Neurospora mitochondria isolated in a Mg2+-containing medium (or after homogenization of the mycelium in this medium and subsequent washing of the mitochondria in EDTA-containing medium) possess 80-S ribosomes; mitochondria homogenized and isolated in EDTA medium yield 73-S ribosomes. The ribosomal proteins of the subunits of 80-S and 73-S ribosomes were compared by two-dimensional electrophoresis. The protein patterns of the large, as well as of the small subunits are very similar but not completely identical; the most conspicuous difference is that the large subunit of 80 S contains about eight more proteins than the large subunit of 73 S. 2. The contamination by Neurospora cytoplasmic 77-S ribosomes in the 80-S preparations, if present, is only minor. 3. Neurospora cytoplasmic ribosomes contain 31 proteins in the large, and 21 proteins in the small subunit. 4. Neurospora 80- mitochondrial ribosomes contain 39 proteins in the large, and 30 proteins in the small subunit 30 proteins. 5. Rat liver mitochondrial ribosomes contain 40 proteins in the large and at least 30 proteins in the small subunit. About 50% of these proteins has an isoelectric point below pH 8.6. 6. The pattern of Paracoccus denitrificans is very similar to that of other bacterial ribosomes, the large subunit contains 29, the small subunit 18 proteins.

Animals↗
PubMedDate not supplied

The impact of a computer-tailored nutrition intervention.

BACKGROUND: Nutrition education tailored to individual characteristics of people might be more effective than general nutrition education. Nowadays, the use of computers makes individualized feedback available for larger groups. METHODS: The impact of tailored nutrition information on changes in fat, vegetable, and fruit consumption was tested in a randomized trial among 347 employees of a major oil company. Respondents in the experimental group received computer-generated feedback letters tailored to their personal dietary behavior, attitudes, perceived social influences, self-efficacy expectations, and awareness levels. Respondents in the control group received general nutrition information. RESULTS: Respondents in the experimental group decreased their fat consumption significantly more than the control group between baseline and posttest. A significant effect of tailoring was also found for changes in attitudes and intentions toward reducing fat intake and increasing fruit and vegetable consumption. Furthermore, respondents in the experimental group were more satisfied with the nutrition information they received and more often reported changing their diet or intention as a result of the information. CONCLUSIONS: It is concluded that computer-tailored nutrition information is a promising means of stimulating people to change their diet toward dietary recommendations.

Analysis of Variance↗
PubMedDate not supplied

Saying "no" to environmental tobacco smoke: determinants of assertiveness among nonsmoking employees.

BACKGROUND: Nonsmokers' assertiveness can help regulate smoking in worksites by enhancing the salience of nonsmoking social norms. This study examined determinants of employees' assertiveness toward smoking colleagues. METHODS: Cross-sectional data were collected from 898 nonsmoking Dutch employees. Potential determinants were chosen using the attitude-social influence-efficacy model. RESULTS: Fifty-one percent of nonsmoking employees asked co-workers not to smoke. Assertive respondents had colleagues who more often acted assertively toward smokers at work, had a more positive attitude to asking colleagues not to smoke, and had a higher perceived self-efficacy. Moreover, assertive employees more often perceived hindrance from environmental tobacco smoke (ETS) and had more negative beliefs about ETS at work. CONCLUSIONS: What matters is whether ETS is perceived as bothersome and harmful. It is likely that both conditions must be met for nonsmokers to behave assertively. Worksite educational programs could focus more on increasing nonsmokers' awareness of the harmfulness of regular exposure to ETS at work to increase social pressure on employees who smoke in places that are shared by smokers and nonsmokers. However, the effectiveness of such strategies is yet unknown.

Adult↗
PubMedDate not supplied

Cost-effectiveness of smoking cessation modalities: comparing apples with oranges?

BACKGROUND: Although the results of self-help and group treatments for smoking cessation are known, the cost effectiveness and participants' characteristics of these treatments remain mostly undetermined. METHODS: Consecutive samples of 84 self-help manual requesters and 83 group participants in a Dutch community-based smoking cessation program were subjected to telephone interviews before treatment and after a 6-month follow-up. Participants' baseline characteristics were compared and contrasted with a random sample of nonparticipating smokers (N = 924). Cost effectiveness rates were computed from the perspectives of the society, the steering group, and the participants. RESULTS: Participants appeared to be more "hardcore smokers" than nonparticipants. Self-help manual requesters seemed easier quitters than group participants. Self-help was at least three times as cost effective as group treatment from the perspective of the program provider and over four times as cost effective from the viewpoint of the participants. When taking savings through not smoking into account, return on the social investment was positive. CONCLUSIONS: From a social perspective, the project seemed cost effective, compared with medical interventions. Since both modalities attracted different groups of smokers, cost effectiveness comparisons may incorporate the comparison of apples with oranges, and referral to either modality should be based on smokers' characteristics and the societal value placed on health as well.

Adult↗
PubMedDate not supplied

Participation in a breast cancer screening program: influence of past behavior and determinants on future screening participation.

BACKGROUND: This study analyzed the relationship between past screening behavior, determinants, intention, and future screening participation in the Dutch national breast cancer screening program. METHODS: Participation at the first and second screening rounds was monitored. Furthermore, between the first and the second screening rounds, women received a questionnaire (response 58%, n = 395). The questionnaire was based on the ASE model, including attitude (consequences, anticipated regret, and moral obligation), social influence (support and modeling), and self-efficacy. Other distal variables assessed were previous screening behavior, evaluation of screening characteristics, and demographics. RESULTS: Participants at the second screening differed from nonparticipants on all ASE determinants. Stepwise multiple regression analyses showed that for previous participants and nonparticipants different ASE determinants and distal variables explained the variance in intention to participate in the next screening (30 to 45%). Logistic regression analyses showed that past behavior and intention (which mediated the effects of the ASE variables) were significant predictors of participation in the second screening. CONCLUSIONS: Differences between previous participants and nonparticipants in determinants of intention and future screening behavior can be used to improve participation and adherence to breast cancer screening.

Aged↗
PubMedDate not supplied

Antecedents of smoking cessation among adolescents: who is motivated to change?

BACKGROUND: In recent years many longitudinal studies have examined the predictors of smoking acquisition. However, only a few studies have focused on the precursors of smoking cessation. The current study is one of the first concentrating on longitudinal predictors of young people's smoking cessation. METHODS: Subjects were 215 smokers ages 14-15 years who were reinterviewed 3 years later. These smokers were allocated to four groups based on their motivation to quit and actual quitting behavior at the last wave. Independent variables were smoking-specific cognitions, social influences, and aspects of smoking habits. RESULTS: Univariate comparisons between the four groups showed that those with a positive attitude toward smoking and lower self-efficacy were less likely to be motivated to quit 3 years later. No long-term effects of environmental influences were found. Aspects of smoking habits, such as intensity and frequency of smoking, and the context of cigarette use affected the motivation to quit. Logistic regression analyses were conducted to examine differences in predictors between the groups in more detail. These analyses revealed that differences mainly in attitudes and self-efficacy affected whether subjects were absolutely not motivated to quit or had actually quit 3 years later. Differences in smoking behavior affected the allocation to the more closely related groups (e.g., preparing versus quitting). CONCLUSIONS: Adolescents' motivation to quit is affected by smoking-related cognitions and habitual factors. More research is needed to decide whether the relation between intensity and frequency of smoking and the likelihood to quit later on should be interpreted in terms of differences in smoking initiation or in terms of preparation to quit.

Adolescent↗
PubMedDate not supplied

Psycho-social determinants and motivational phases in smoking behavior of cardiac inpatients.

BACKGROUND: To explore possibilities for health education, this study analyzed the differences in motives regarding smoking cessation of cardiac inpatients in various motivational phases. The Attitude-Social influence-Efficacy Model (ASE model) was used to assess motives, while motivational phases were measured with concepts from the Transtheoretical Model. METHODS: Data on smoking behavior, attitudes, social influences, self-efficacy expectations, and motivational phases were collected from a sample of 532 cardiac inpatients. A revised typology of the Transtheoretical Model was used for measuring motivational phases and resulted in four groups: smokers in precontemplation, smokers in contemplation, externally motivated actors, and internally motivated actors. Analysis of variance with Tukey's multiple comparison test was used to study differences in psycho-social determinants between these four groups. RESULTS: As hypothesized, externally motivated actors differed from internally motivated actors in having less positive attitudes, less social support, and lower self-efficacy expectations. Attitudes and social support were most positive among smokers in contemplation and internally motivated actors. Self-efficacy expectations were lowest among subjects in precontemplation and contemplation. CONCLUSIONS: Subjects in different motivational phases differed in their psycho-social determinants. Therefore, it is recommended that stage-tailored education be developed. Finally, externally motivated actors have to be approached in a different way than internally motivated actors.

Analysis of Variance↗