Biomedical subjects

R Alcaraz

Publications and source records attributed to R Alcaraz.

6 recordsLinked to original sources

PubMed1999

Site-specific recombination of bacteriophage P22 does not require integration host factor.

Site-specific recombination by phages lambda and P22 is carried out by multiprotein-DNA complexes. Integration host factor (IHF) facilitates lambda site-specific recombination by inducing DNA bends necessary to form an active recombinogenic complex. Mutants lacking IHF are over 1,000-fold less proficient in supporting lambda site-specific recombination than wild-type cells. Although the attP region of P22 contains strong IHF binding sites, in vivo measurements of integration and excision frequencies showed that infecting P22 phages can perform site-specific recombination to its maximum efficiency in the absence of IHF. In addition, a plasmid integration assay showed that integrative recombination occurs equally well in wild-type and ihfA mutant cells. P22 integrative recombination is also efficient in Escherichia coli in the absence of functional IHF. These results suggest that nucleoprotein structures proficient for recombination can form in the absence of IHF or that another factor(s) can substitute for IHF in the formation of complexes.

Attachment Sites, Microbiological↗

PubMed1997

An experimental analysis of sociocultural variables in sales of cigarettes to minors.

OBJECTIVES: This study assessed the role of age, racial/ethnic group, and gender, as well as that of other sociocultural variables, in minors' access to tobacco. METHODS: Thirty-six minors attempted to purchase cigarettes once in each of 72 stores (2592 purchase attempts). The minors represented equal numbers of girls and boys; 10-year-olds, 14-year-olds, and 16-year-olds; and Whites, Blacks, and Latinos. Equal numbers of stores were in Black, White, and Latino neighborhoods. RESULTS: Older children were more likely than younger ones to be sold cigarettes, and Latino children were more likely than Whites to be sold cigarettes. Older Black children (irrespective of gender) were the single most likely group to be sold cigarettes. Cigarettes were significantly more likely to be sold to children by male than female clerks and in specific sociocultural contexts. CONCLUSIONS: Interventions with retailers must address sociocultural variables to improve effectiveness in reducing minors' access to tobacco.

Adolescent↗

PubMedDate not supplied

Asking age and identification may decrease minors' access to tobacco.

BACKGROUND: Many merchant education programs entail efforts to increase cashiers' requests for minors' age and/or identification (proving themselves old enough to purchase cigarettes) as a means of decreasing minors' access to tobacco. However, whether such questions are actually associated with decreased sales to minors has never been investigated. We present the first investigation of the role of such questions in sales of tobacco to minors. METHODS: Thirty-six minors, representing equal numbers of girls, boys, whites, blacks, and Latinos and of 10-, 14-, and 16-year-olds, each attempted to purchase cigarettes once in each of 72 stores, for a total of 2,567 purchase attempts. The frequency of asking the children their age and/or for identification (ID) was analyzed along with the role of these questions in subsequent sales. RESULTS: The data revealed that requesting age/ID was rare (occurring 17% of the time) despite the laws in California requiring clerks to do so. When age was asked, however, minors were refused cigarettes 95.8% of the time, and when ID was requested, they were refused cigarettes 99.0% of the time. Asking for ID may be more strongly associated with decreased sales than asking age. For example, for 16-year-olds, asking age decreased sales from 57.2% (when no questions were asked) to 8.5% of the time, and asking ID decreased sales to 2.4% of the time. CONCLUSIONS: These data provide empirical support for the widespread belief that the success of interventions with retailers can be improved by enhancing efforts to increase merchants' requests for children's ID.

Adolescent↗

PubMedDate not supplied

The effects on children of participating in studies of minors' access to tobacco.

BACKGROUND: Ethical concerns about the effect on children of participating in studies of minors' access to tobacco are frequently raised by human subjects' committees but have not been assessed empirically. Data on the effects of such participation on the smoking-related behavior of minors are needed. METHOD: Forty-eight children were screened and selected in 1993 to participate in a study of minors' access to tobacco. All 48 attended tobacco-education workshops, none were smokers, and all denied an intention to smoke in the future. Thirty-six of them were (randomly) assigned to the experimental group who made 2,567 purchase attempts (PAs) between 1993 and 1994, and 11 were assigned to a control group who made no PAs. Two years after screening (1 year after completion of the study) all were sent a follow-up questionnaire assessing current intentions to smoke and other smoking-related behaviors. RESULTS: Minors who made PAs were significantly less likely than those who did not to indicate an intention to smoke in the future; only 12.5% of experimental vs 71.4% of control group minors intended to (or might) smoke in the future. Minors who made PAs also were significantly more likely than those who had not to discuss smoking with peers and to encourage peers and family to quit smoking or to avoid initiating smoking. In 2,567 PAs, minors were never physically threatened, touched, or harmed, and they were treated with verbal hostility in only 73 (2.8%) of their PAs. CONCLUSIONS: These findings suggest that participating in a study of minors' access to tobacco does not increase smoking or intentions to smoke among the minors. Rather, such participation may be associated with low intentions to smoke and with increased tobacco-control efforts on the part of the minors. The effects of participating in such studies may be positive for the minors, their families, and their peers. Participating in such studies does not place minors at risk for physical harm, and their risk for verbal abuse is low.

Adolescent↗

PubMedDate not supplied

Minors' access to single cigarettes in California.

OBJECTIVE: As the cost of a pack of cigarettes continues to increase, minors may resort to purchasing single cigarettes ("loosies"), but no clear data on their rate of access to singles are available. This study examined the availability of singles to minors by gender, age, and ethnicity. DESIGN: In a factorial experiment, 36 minors of different sexes, ages, and ethnic groups each attempted to purchase a single cigarette once in half of a group of 72 randomly selected stores in middle-class California communities, for a total of 1,271 single cigarette purchase attempts. RESULTS: Minors were able to purchase singles 7.9% of the time, with this access rate being significantly higher (16.2%) for older (16-year-old) minors. Minors were typically charged 15 cents for the single, and singles were sold by 28 of the 72 (38.9%) stores. CONCLUSIONS: Minors have considerable access to single cigarettes in middle-class, California communities, despite California laws banning their sale. Minors' rate of access to singles in poorer communities and in states that lack legislation against selling them is probably significantly higher. Because singles facilitate cigarette purchases by minors who lack money, any legislation that increases the cost of a pack of cigarettes must also explicitly ban the sale of singles.

Adolescent↗

PubMedDate not supplied

An instrument for assessing the quality of tobacco-control policies: the ACT-L scale.

BACKGROUND: Efforts to prevent and decrease tobacco use and tobacco-related disease include improving the quality of tobacco-control laws to make them more stringent in controlling tobacco advertising, youth access, and exposure to environmental tobacco smoke (ETS). However, because there are no instruments to empirically evaluate the quality of such laws, it has been difficult to demonstrate that their quality is associated with decreased youth access or tobacco-related morbidity. We present the first instrument for empirically assessing the quality of tobacco-control policies. METHODS: Recommendations for the content of an ideal, comprehensive tobacco-control policy were used as the 55 items in the Assessment of the Comprehensiveness of Tobacco Laws Scale (ACT-L Scale). Raters evaluated 71 tobacco-control laws with the scale; 70 of these were actual California laws and 1 was a model law from Americans for Non-smokers' Rights (ANR). RESULTS: Interrater (r = 0.64-0.89) and internal-consistency (r = 0.63-0.88) reliability of the scale and subscales were high, and validity was established by demonstrating that the ANR model law received a significantly higher total score (mean = 18.75) than all actual laws (mean = 2.04). California tobacco-control laws were poor in all areas (youth access, ETS, tobacco advertising). CONCLUSIONS: The ACT-L scale can be used to compare and evaluate the quality of tobacco-control laws, highlight areas in which further policy efforts are needed, quantify improvement in such policies, and empirically demonstrate the positive health impact of high-quality tobacco-control laws.

Adolescent↗