Psychosocial and environmental predictors of calcium intake, physical activity and bone health among adolescent girls

Objectives. The purpose of this study was to identify the psychosocial and environmental predictors and the pathways they use to influence calcium intake, physical activity and bone health among adolescent girls. Methods. A secondary data analysis using a cross-sectional and longitudinal study design was implemented to examine the associations of interest. Data from the Incorporating More Physical Activity and Calcium in Teens (IMPACT) study collected in 2001-2003 were utilized for the analyses. IMPACT was a 1½ year nutrition and physical activity intervention study conducted among 718 middle-school girls in central Texas. Hierarchical regression modeling and Structural Equation Modeling (SEM) were used to determine the psychosocial predictors of calcium intake, physical activity and bone health at baseline. Hierarchical regression was used to determine if psychosocial factors at baseline were significant predictors of calcium intake and physical activity at follow-up. Data was adjusted for included BMI, lactose intolerance, ethnicity, menarchal status, intervention and participation in 7th grade PE/athletics. Results. Results of the baseline regression analysis revealed that calcium self-efficacy and milk availability at home were the strongest predictors of calcium intake. Friend engagement in physical activity, physical activity self-efficacy and participation in sports teams were the strongest predictors of physical activity. Finally, physical activity outcome expectations, social support and participation in sports teams were significant predictors of stiffness index at baseline. Results of the baseline SEM path analysis found that outcome expectations and milk availability at home directly influenced calcium intake. Knowledge and calcium self-efficacy indirectly influenced calcium intake with outcome expectations as the mediator. Physical activity self-efficacy and social support had significant direct and indirect influence on physical activity with participation in sports teams as the mediator. Participation in sports teams had a direct effect on both physical activity and stiffness index. Results of regression analysis for baseline predicting follow-up showed that participation in sports teams, self-efficacy, outcome expectations and social support at baseline were significant predictors of physical activity at follow-up. Conclusion. Results of this study reinforce the relevance of addressing both, psychosocial and environmental factors which are critical when developing interventions to improve bone health among adolescent girls. ^

Studies on behavioral regulations of morphine tolerance in rats

Opioids remain the drugs of choice in chronic pain treatment, but opioid tolerance, defined as a decrease in analgesic effect after prolonged or repeated use, dramatically limits their clinical utility. Opioid tolerance has classically been studied by implanting spinal catheters in animals for drug administration. This procedure has significant morbidity and mortality, as well as causing an inflammatory response which decreases the potency of opioid analgesia and possibly affects tolerance development. Therefore, we developed and validated a new method, intermittent lumbar puncture (Dautzenberg et al.), for the study of opioid analgesia and tolerance. Using this method, opioid tolerance was reliably induced without detectable morbidity. The dose of morphine needed to induce analgesia and tolerance using this method was about 100-fold lower than that required when using an intrathecal catheter. Only slight inflammation was found at the injection site, dissipated within seven mm. ^ DAMGO, an opioid μ receptor agonist, has been reported to inhibit morphine tolerance, but results from different studies are inconclusive. We evaluated the effect of DAMGO on morphine tolerance using our newly-developed ILP method, as well as other intrathecal catheter paradigms. We found that co-administration of sub-analgesic DAMGO with morphine using ILP did not inhibit morphine tolerance, but instead blocked the analgesic effects of morphine. Tolerance to morphine still developed. Tolerance to morphine can only be blocked by sub-analgesic dose of DAMGO when administered in a lumbar catheter, but not in cervical catheter settings. ^ Finally, we evaluated the effects of Gabapentin (GBP) on analgesia and morphine tolerance. We demonstrated that GBP enhanced analgesia mediated by both subanalgesic and analgesic doses of morphine although GBP itself was not analgesic. GBP increased potency and efficacy of morphine. GBP inhibited the expression, but not the development, of morphine tolerance. GBP blocked tolerance to analgesic morphine but not to subanalgesic morphine. GBP reversed the expression of morphine tolerance even after tolerance was established. These studies may begin to provide new insights into mechanisms of morphine tolerance development and improve clinical chronic pain management. ^

A systematic review of community-based participatory research interventions in pediatric and adolescent populations

Background. Community-based participatory research (CBPR) is a collaborative approach to research actively involving community members in all aspects of the research process. CBPR is not a new research method, but an approach that has gained increased attention in the field of public health over the last several years. Recognition of the inequalities in health status associated with social and environmental factors have led to calls for a renewed focus on ecological approaches to research. Ecological approaches acknowledge that the health of the community is dependent on an interaction between behavioral and environmental factors affecting the entire population. While many published studies document the benefits of CBPR in difficult-to-reach populations and describe successful implementation of this approach in adult populations, relatively few studies have been conducted in child and adolescent populations. Given that children and adolescents are particularly sensitive to the effects of their physical environments and may also be distrustful of outsiders, ecological approaches involving the community as partners, such as CBPR, may be especially useful in this population. ^ Objective. This thesis reviews published studies using a community-based participatory research approach in children and adolescents to assess the appropriateness of this approach in this population. ^ Method. Studies using CBPR in youth populations were identified using Medline and other Internet searches through both MeSH heading and text-word searches. ^ Results. A total of 16 studies were identified and analyzed for this review. Nine of the sixteen studies were experimental or quasi-experimental design, with Asthma being the most commonly studied disease. ^ Conclusions. While many studies using CBPR were not conducted with the level of scientific rigor typically found in clinical trial research, the studies reviewed each contributed to a greater understanding of the problems they investigated. Furthermore, interventional studies provided lasting benefits to communities under study above what would be found in studies using more traditional research approaches. While CBPR may not be appropriate for all research situations due to the time and resources required, we conclude that is a useful approach and should be considered when conducting community-based research for pediatric and adolescent populations.^

Marketing physical activity and healthy eating: A literature review of recent social marketing campaigns and development of a social marketing plan for the CATCH program

Background. This culminating experience project was inspired by an independent study conducted at The University of Texas School of Public Health with Dr. Andrew Springer, DrPH, who works on the evaluation of the Coordinated Approach to Child Health (CATCH) program in Travis County, Texas. It was indicated that a social marketing plan could enhance current efforts for the CATCH program. The aims of the project were to (1) review and synthesize literature on social marketing, with a specific focus on diet, physical activity, and obesity prevention; and (2) apply the gained knowledge toward a practical solution – a social marketing plan for the CATCH program.^ Methods. The literature review aimed to answer the following questions: (1) What audiences (ethnic and age groups), settings, health behaviors, and behavioral science theories have been used in social marketing campaigns? (2) What features of social marketing were used (e.g. formative research, segmentation, and the marketing mix - including promotional strategies and communication channels)? (3) What were the outcomes of the social marketing campaigns? The search aimed to identify studies that met the following inclusion criteria: (a) The study explicitly stated that social marketing was used; (b) The intervention promoted physical activity and/or healthy eating; (c) The population was children, adolescents, young adults, and/or parents; (d) Results of the intervention were available in the published literature The literature review includes studies from the past five years (2004 to 2009). After reviewing the social marketing literature, the insight and knowledge gained was applied to develop a social marketing plan for the CATCH program. The plan was guided by Hands-on Social Marketing, A Step-by-Step Guide and the Center for Disease Control and Prevention's Social Marketing web course.^

Social cognitive theory and factors associated with Mexican-American parents' beliefs, attitudes and practices regarding communication with their adolescent children about sex

Latinos have the highest teen birth rate nationally. Cameron County, Texas is primarily Latino (Mexican-American). This mixed-method study (n=43) examines Mexican-American parents of adolescents' beliefs, attitudes and practices regarding communication with their adolescent children about sex. Social Cognitive Theory (SCT) constructs self-efficacy, behavioral determinism, environment, outcome expectations and reciprocal determinism can be influences on frequency and quality of parent-adolescent sex communication.^ This study describes Mexican-American parents' of adolescents recollections of their own experiences associated with learning about sexuality. It also examines the attitudes and practices regarding communication about sex and the self-efficacy and behavioral capability of participants to teach their adolescent children about sex and sexually transmitted infections. ^ Negative childhood experiences (shame, lies and trauma) of the parents in this study played a key role in terms of their desire to communicate more comprehensively about sexuality with their own children than did their parents. While participants' reported low self-efficacy and behavioral capability to communicate with their adolescent children about sex, they reported relatively high frequency and quality of communication, with 75% of participants receiving a high quality score and over 44% reporting frequent communication with their adolescent children about sex. A Chi square analysis and Fisher's Exact Score revealed no association between acculturation status, gender or having a child who has mothered/fathered a baby and the frequency or quality of communication about sex with adolescent children. Study participants also gave specific recommendations for method, content and setting of sex education for their children and themselves. Promotora delivery of information and education in a comfortable, culturally appropriate neighborhood setting, as well as parent –child learning sessions were identified as possible approaches to address improve self-efficacy and behavioral capability of parents communicating with their adolescent children about sex.^ The results of this analysis provide public health practitioners and interested community entities data to identify and develop interventions that use a theoretical, evidence-based framework for culturally appropriate interventions to encourage and equip Mexican-American parents to effectively communicate with their adolescent children about sexuality, and ultimately to address the high rates of teen pregnancy in this U.S.-Mexico border community. ^

African American and Hispanic adolescent STI and pregnancy prevention: Whose responsibility is it, anyway?

This dissertation utilized quantitative and qualitative methods to examine the role of responsibility in the prevention of sexually transmitted infections (STIs) and pregnancy through condom use and other sexual behaviors among young adolescents. Data were analyzed across race and gender and three papers were developed. The quantitative portion used logistic regression to assess associations between personal responsibility, as well as other know correlates, and reported condom use and condom use intentions as a means of STI and pregnancy prevention among 445 inner-city, high school adolescents. Responsibility to prevent pregnancy by providing the condom was associated with condom use at last sex and consistent condom use. Responsibility to prevent acquiring a STI by using a condom was significantly associated with consistent condom use. No significant associations were found between responsibility and condom use intentions. ^ The qualitative section of the dissertation project involved conducting 28 in-depth interviews among 9th and 10th grade, African American and Hispanic students who attended a large urban school district in South Central Texas. Perceptions of responsibility for preventing STIs and unintended pregnancy, as well as for condom use, were explored. Male and female adolescents expressed joint responsibility to prevent a STI or pregnancy. Perceptions of responsibility for providing and using the condoms were mixed. Despite the indication of both partners, mostly all participants implied that females, more so than the males, had the final responsibility to prevent contracting a STI, a pregnancy, to provide a condom, and to make sure a condom was used. Participants expressed the role of parents' involvement for preventing these outcomes as well as the need for more sexual health education and access to preventative methods. ^ The last section of this dissertation involved qualitative inquiry to ascertain perceptions of reasons why adolescents engage in anal and oral (non-coital) sex. Pleasure-seeking and giving as well social influence and pressure were described as the main reasons why teenagers have non-coital sex. Other reasons included conveniences of participating in these behaviors such as ease of performing oral sex and anal sex as a convenient alternative to vaginal sex. Sexual inexperience was an indicator for why anal sex occurs. Many of the reasons involved misperceptions and adolescents who practice these sexual behaviors place themselves at-risk for contracting a STI. ^ This dissertation increased the current knowledge base about adolescent sexual responsibility and non-coital behaviors. Future studies should explore perceptions of responsibility and actual sexual activity practices among adolescents to reduce the burden of STIs and pregnancy as well as help public health professionals develop programs for adolescent populations, schools, and communities where these issues persist.^

An evaluation of a behavioral change intervention for smokeless tobacco use

During the last three decades considerable attention has been placed on the reduction of tobacco use due to cigarette smoking. During this time, studies have been funded and programs have been developed that focus on both prevention and cessation of cigarette smoking. This intense focus has led to a significant decline in cigarette smoking. But now, use of another form of tobacco--smokeless tobacco--is gaining in popularity.^ In 1989, the National Cancer Institute funded a research study at The University of Texas M. D. Anderson Cancer Center, called Working Well, to develop, implement, and evaluate worksite health promotion programs aimed at reducing cancer risks. As part of this program, a behavioral intervention for smokeless tobacco use was developed. This dissertation evaluates the impact of that behavioral change intervention for smokeless tobacco use.^ Data collected during the Working Well program were analyzed to determine the effect of the intervention. The primary outcomes analyzed were smokeless tobacco cessation, stages of change movement, and prevalence. The secondary outcomes analyzed included the prediction of smokeless tobacco use, stage movement, and cessation. Primary outcome analyses were conducted using the worksite as the unit of analysis, while the secondary analyses were conducted using the individual as the unit of analysis.^ Approximately 20% of the male population used smokeless tobacco. Results of intervention analyses indicate that the Working Well program produced no intervention effect on any of the primary outcomes. At the final observation, the experimental worksites achieved a quit rate of 27%, while the control worksites achieved a quit rate of 26% (P = 0.78). Stage movement for the experimental worksites was 49%, while the control worksites experienced stage movement of 43% (P = 0.20). The results of the analyses on smokeless tobacco prevalence followed the same pattern. Predictors of smokeless tobacco use, cessation, and stage movement were also identified.^ Based on the results found in this study, smokeless tobacco should remain a research priority. Future research should focus on smokeless tobacco use, including the identification of the determinants of smokeless tobacco use and the development of measures and effective intervention strategies. ^

SOCIAL, ATTITUDINAL AND BEHAVIORAL CORRELATES OF WEIGHT CHANGE AMONG MEXICAN AMERICAN WOMEN (OBESITY, DIET, TEXAS)

In industrialized countries the prevalence of obesity among women decreases with increasing socioeconomic status. While this relation has been amply documented, its explanation and implications for other causal factors of obesity has received much less attention. Differences in childbearing patterns, norms and attitudes about fatness, dietary behaviors and physical activity are some of the factors that have been proposed to explain the inverse relation.^ The objectives of this investigation were to (1) examine the associations among social characteristics and weight-related attitudes and behaviors, and (2) examine the relations of these factors to weight change and obesity. Information on social characteristics, weight-related attitudes, dietary behaviors, physical activity and childbearing were collected from 304 Mexican American women aged 19 to 50 living in Starr County, Texas, who were at high risk for developing diabetes. Their weights were recorded both at an initial physical examination and at a follow-up interview one to two and one-half years later, permitting the computation of current Body Mass Index (weight/height('2)) and weight change during the interval for each subject. Path analysis was used to examine direct and indirect relations among the variables.^ The major findings were: (1) After controlling for age, childbearing was not an independent predictor of weight change or Body Mass Index. (2) Neither planned exercise nor total daily physical activity were independent predictors of weight change. (3) Women with higher social characteristics scores reported less frequent meals and less use of calorically dense foods, factors associated with lower risk for weight gain. (4) Dietary intake measures were not significantly related to Body Mass Index. However, dietary behaviors (frequency of meals and snacks, use of high and low caloric density foods, eating restraint and disinhibition of restraint) did explain a significant portion (17.4 percent) of the variance in weight change, indicating the importance of using dynamic measures of weight status in studies of the development of obesity. This study highlights factors amenable to intervention to reverse or to prevent weight gain in this population, and thereby reduce the prevalence of diabetes and its sequelae. ^

Parental influence on adolescent smoking initiation among Mexican origin youth

Smoking is often initiated in adolescence through trying or experimenting with cigarettes. Smoking initiation is the beginning critical stage in the smoking trajectory often resulting in addiction. This dissertation examined the effect of parenting variables on smoking initiation behavior among 11–14 year old Mexican origin adolescents, a largely understudied group. The participants in this study were part of a population-based cohort of Mexican origin adolescents residing in Houston, Texas. ^ Aim 1 of this study assessed the appropriateness of the Family Life Questionnaire (FLQ) among Mexican origin adolescents. Second order confirmatory factor analysis (CFA) was performed to examine the factor structure of the FLQ and measurement invariance testing was conducted to evaluate the cross-cultural validity of this scale. Aim 2 analyzed cross-sectional associations between parenting variables and adolescent ever tried smoking behavior while aim 3 focused on prospective examination of changes in parenting variables from baseline to final follow-up on ever tried smoking behavior among never smokers. ^ Overall, the results of the CFA indicated that the original factor structure of the FLQ, with alterations, was a good fit for the Mexican origin adolescents. The measurement invariance analysis of the modified FLQ scale indicated adequate measurement invariance. The aim 2 cross-sectional analyses indicated that family cohesion was significantly associated with lower odds of ever tried smoking. Authoritarian parenting was significantly associated with smoking initiation only at the baseline while family conflict was significantly associated with smoking initiation only at the two-year final home visit. The findings from the aim 3 prospective analysis indicated that changes in levels of family cohesion and conflict are important predictors of smoking initiation among those who have never tried smoking. Specifically, perceiving low levels of family cohesion and a decrease in the family cohesion over two years, as well as perceiving high levels of family conflict and an increase in conflict over two years was associated with smoking initiation among never smokers. ^ In general, the findings of this study provide important insights on the links between parenting and adolescent smoking and assist in designing prevention and intervention programs that emphasize the role of family bonding to prevent adolescent smoking behavior. Family education programs for Mexican culture could also highlight the positive effects of authoritarian practices and good family communication to prevent family conflict and subsequent smoking behavior.^

Association of coping styles & adolescent substance use

Adolescent substance use is a serious public health concern with long-lasting consequences. Although specific coping behaviors have been associated with adolescent substance use, less is known about the role of multidimensional coping styles that account for both positive and negative coping behaviors. This study examined the association of coping styles and substance use (alcohol, marijuana, and other illicit drugs) of 1,019 ethnically diverse high school students. Coping styles were categorized by high or low negative coping behaviors (e.g. distraction, social withdrawal, self-criticism, blame others, wishful thinking, resignation, and negative emotional regulation) and high or low positive coping behaviors (e.g. cognitive restructuring, problem-solving, social support, and positive emotional regulation). My hypothesis that high positive coping, regardless of the use of negative coping behaviors, would be protective against substance use was rejected. Logistic regression analyses controlling for age, gender, race, and parent education indicated that adolescents who relied primarily on adaptive coping were 45-67% less likely to report lifetime or past year substance use than any other coping style. However, mixed copers (i.e. high in both positive and negative coping behaviors) were 2 to 3 times as likely to report substance use than their adaptive coping counterparts.^

Understanding and Characterizing Shared Decision-Making and Behavioral Intent in Medical Uncertainty

Applying Theoretical Constructs to Address Medical Uncertainty Situations involving medical reasoning usually include some level of medical uncertainty. Despite the identification of shared decision-making (SDM) as an effective technique, it has been observed that the likelihood of physicians and patients engaging in shared decision making is lower in those situations where it is most needed; specifically in circumstances of medical uncertainty. Having identified shared decision making as an effective, yet often a neglected approach to resolving a lack of information exchange in situations involving medical uncertainty, the next step is to determine the way(s) in which SDM can be integrated and the supplemental processes that may facilitate its integration. SDM involves unique types of communication and relationships between patients and physicians. Therefore, it is necessary to further understand and incorporate human behavioral elements - in particular, behavioral intent - in order to successfully identify and realize the potential benefits of SDM. This paper discusses the background and potential interaction between the theories of shared decision-making, medical uncertainty, and behavioral intent. Identifying Shared Decision-Making Elements in Medical Encounters Dealing with Uncertainty A recent summary of the state of medical knowledge in the U.S. reported that nearly half (47%) of all treatments were of unknown effectiveness, and an additional 7% involved an uncertain tradeoff between benefits and harms. Shared decision-making (SDM) was identified as an effective technique for managing uncertainty when two or more parties were involved. In order to understand which of the elements of SDM are used most frequently and effectively, it is necessary to identify these key elements, and understand how these elements related to each other and the SDM process. The elements identified through the course of the present research were selected from basic principles of the SDM model and the “Data, Information, Knowledge, Wisdom” (DIKW) Hierarchy. The goal of this ethnographic research was to identify which common elements of shared decision-making patients are most often observed applying in the medical encounter. The results of the present study facilitated the understanding of which elements patients were more likely to exhibit during a primary care medical encounter, as well as determining variables of interest leading to more successful shared decision-making practices between patients and their physicians. Understanding Behavioral Intent to Participate in Shared Decision-Making in Medically Uncertain Situations Objective: This article describes the process undertaken to identify and validate behavioral and normative beliefs and behavioral intent of men between the ages of 45-70 with regard to participating in shared decision-making in medically uncertain situations. This article also discusses the preliminary results of the aforementioned processes and explores potential future uses of this information which may facilitate greater understanding, efficiency and effectiveness of doctor-patient consultations.Design: Qualitative Study using deductive content analysisSetting: Individual semi-structure patient interviews were conducted until data saturation was reached. Researchers read the transcripts and developed a list of codes.Subjects: 25 subjects drawn from the Philadelphia community.Measurements: Qualitative indicators were developed to measure respondents’ experiences and beliefs related to behavioral intent to participate in shared decision-making during medical uncertainty. Subjects were also asked to complete the Krantz Health Opinion Survey as a method of triangulation.Results: Several factors were repeatedly described by respondents as being essential to participate in shared decision-making in medical uncertainty. These factors included past experience with medical uncertainty, an individual’s personality, and the relationship between the patient and his physician.Conclusions: The findings of this study led to the development of a category framework that helped understand an individual’s needs and motivational factors in their intent to participate in shared decision-making. The three main categories include 1) an individual’s representation of medically uncertainty, 2) how the individual copes with medical uncertainty, and 3) the individual’s behavioral intent to seek information and participate in shared decision-making during times of medically uncertain situations.

Exploring parental factors and their influence on early adolescent sexual health

Black and Hispanic youth experience the largest burden of sexually transmitted infections, teen pregnancy, and childbirth (Hamilton, Martin, & Ventura, 2011). Minority youth are disporportionately more likely to sexually debut at every age and debut before the age of 13 compared to whites (Centers for Disease Control and Prevention, 2011). However, there is little known about pre-coital sexual activity or protective parental factors in early adolscent minority youth. Parental factors such as parent-child communication and parental monitoring influence adolescent sexual behaviors and pre-coital sexual behaviors in early adolescence. Three distinct methods were used in this dissertation. Study one used qualitative methods, semi-structured, in-depth, individual interviews, to explore parent-child communication in African American mother-early adolescent son dyads. Study two used quantitative methods, secondary data analysis of a cross sectional study, to conduct a moderation analysis. For study three, I conducted a systematic review of parent-based adolescent sexual health interventions. Study one found that mothers feel comfortable talking about sex with adolescents, provide a two-prong sexual health message, and want their sons to tell their when they are thinking of having sex. Study found that parental monitoring moderates the relation between parent-child communication and pre-coital sexual behaviors. Study three found that interventions use a variety of theory, methods, and strategies and that no parent-based programs target faith-based organizations, mother-son or father-daughter dyads, or parents of LGBTQ youth. Adolescent sexual health interventions should consider addressing youth-to-parent disclosure of sexual activity or intentions to debut, addressing both parent-child sexual health communication and parental monitoring, and using a theoretical framework.^

Ethnic comparisons of adolescent sexual risk -taking and preventive behavior

For adolescents, unprotected sexual intercourse is the primary cause of sexually transmitted disease (STD), including Human Immunodeficiency Virus (HIV) infection (virus which causes Acquired Immunodeficiency Syndrome (AIDS)), and pregnancy. Although many studies on adolescent sexual behavior have addressed racial/ethnic differences, few studies have examined the relation between race/ethnicity while controlling for other sociocultural and psychosocial variables. The purpose of this study is to examine the relationship between racial/ethnic categories and selected sociocultural and psychosocial variables, with reported adolescent sexual risk-taking and preventive behavior.^ A self-administered questionnaire was used to collect information from 3132 students in a Texas school district (Section 3.5.2). The instrument contained approximately 100 questions on demographic characteristics, sexual behavior, and psychosocial determinants of sexual behavior. Based on the findings of this study, the following major conclusions are made: (1) There are differences in reported sexual risk-taking and preventive behavior among Black, Hispanic and White adolescents in this study. The stratified analysis by gender further suggests significant gender differences in reported sexual behavior among the three racial/ethnic groups. (2) Gender, living arrangement, academic grades, and language spoken at home modified the association between reported sexual risk-taking and preventive behavior and race/ethnicity in this study. This suggests that these sociocultural variables should be considered in future research and practice involving multicultural populations. (3) There are differences in selected psychosocial determinants among the three racial/ethnic groups and between males and females. These differences were consistent with the reported sexual risk-taking and preventive behaviors among race/ethnicity and gender for adolescents in this study. The findings support the consideration of psychosocial determinants in research and interventions addressing adolescent sexual behavior among different racial/ethnic groups.^ Based on the results of this study, two recommendations for practice are made. First, health professionals developing interventions for adolescents from different cultural backgrounds and gender need to be familiar with the specific sociocultural and psychosocial factors which will reduce risky sexual behavior, and promote protective behavior. Second, the need for immediate, realistic, and continuous HIV/STD and pregnancy prevention programs for children and adolescents should be considered. ^

The LPS O -antigen is required for Myxococcus xanthus social motility and multicellular development

The gliding bacterium Myxococcus xanthus aggregates to form spore-filled fruiting bodies when starved at high density. All of the identified M. xanthus lipopolysaccharide (LPS) O-antigen biosynthesis mutants exhibit defective motility and fruiting-body development. To determine the cause of these phenotypes, the cell-surface properties of the LPS O-antigen mutants were compared to wild-type cells. The binding characteristics of wild-type and LPS O-antigen-defective strains to cationic resin indicate that the mutant cell surfaces are more electronegative. Antibiotic sensitivity and hexadecane adhesion assays indicate that the wild-type M. xanthus cell surface is hydrophobic, supporting the idea that phospholipids are present in the outer leaflet of the outer membrane. The absence of the LPS O-antigen appears to expose charges associated with phospholipids and LPS core/lipid A, resulting in a dramatic alteration of the cell-surface organization and charge. These differences may affect the interaction of the LPS O-antigen mutants with their substratum and neighboring cells, leading to defects in social and single-cell gliding motility and thus, deficiencies in fruiting body formation. ^ The LPS O-antigen biosynthetic mutations also bypass the requirement of 4521 gene expression for the cell-density signal, A signal. The 4521 gene is overexpressed in these mutants. This 4521 overexpression is dependent on the sensor kinase SasS. Co-development with wild-type cells, or the addition of crude polysaccharides or membrane vesicles restores the ability of LPS O-antigen mutants to form fruiting bodies and lowers 4521 developmental gene expression to wild-type levels. Wild-type vesicles may attach or incorporate into the outer membrane of the mutants that lack LPS O-antigen, restoring a wild-type periplasmic status and allowing for normal levels of 4521 activity and fruiting body formation. We propose that the LPS composition and the configuration of the outer membrane are important elements for the complex behavioral response of M. xanthus fruiting body development. ^