Body image and physical activity in Latinas

Women with negative body image engage in less physical activity. The purpose of this study is to examine the relationship between body image and physical activity in Latinas participating in a lifestyle program. Participants (age 43.8 ± 10.1 years and BMI 30.4 ± 5.2 kg/m2) were enrolled in a 12-month culturally and linguistically adapted, individually tailored, intervention focused on increasing moderate-to-vigorous intensity physical activity (MVPA). Longitudinal assessments were conducted on body image dissatisfaction (BID) using the Figure Rating Scale, MVPA using the 7-day PAR interview, and objectively measured body weight. Pre-intervention BID did not significantly predict MVPA change. Participants experienced considerable reduction in BID. Greater MVPA engagement and weight loss were independently related to BID reduction. Acculturation did not moderate these relationships. Body image improved in Latinas participating in a cognitive and behavioral physical activity intervention regardless of weight loss and acculturation level.

Barriers and Facilitators to Muscle-Strengthening Activity Among Latinas in the U.S.: Results From Formative Research Assessments

BACKGROUND

Latinas are disproportionately affected by low physical activity (PA) levels and related health conditions (e.g., diabetes, obesity). Few Latinas in the U.S. (17%) meet the National PA Guidelines for both aerobic PA and muscle-strengthening activity (MSA), yet, research to date in this population has focused almost exclusively on aerobic PA. Performing regular MSA is linked with numerous health improvements and reduced mortality; thus, may be key to addressing health disparities in this community. This study examined perspectives on engaging in MSA among Latinas enrolled in two aerobic PA RCTs.

METHODS

Brief quantitative surveys were conducted to assess interest in MSA among Latinas (N = 81), along with 19 follow-up in-depth semi-structured interviews on knowledge, barriers, and facilitators for engaging in regular MSA. Interview transcripts were analyzed by two independent bilingual researchers using a directed content analysis approach.

RESULTS

Eighty-one Latinas (18-65 years) completed the survey. Most (91%) expressed interest in learning more about MSA and 60% reported not knowing how to do MSA as a substantial MSA barrier. Interview results indicated Latinas were aware of health benefits of MSA and motivated to engage in MSA but reported barriers (e.g., perception that MSA is for men, a taboo topic, and lack of knowledge on how to do MSA).

CONCLUSION

This study contributes to a critical gap in PA research among Latinas. Findings will inform future culturally appropriate MSA interventions in this at-risk population. Addressing MSA and aerobic PA together in future interventions will provide a more comprehensive approach to reducing PA-related health disparities in Latinas than aerobic PA alone.

Pasos Hacia La Salud II: A Superiority RCT Utilizing Technology to Promote Physical Activity in Latinas

INTRODUCTION

Latinas face an increased risk for chronic diseases associated with insufficient physical activity (PA). The researchers previously showed that a website-based intervention could increase PA among insufficiently active Latinas, yet rates of meeting national PA guidelines were low. The original intervention was enhanced by adding additional features, content, and points of contact, including via text messaging. This study tests the efficacy of the enhanced intervention compared with the original, aimed at maximizing and sustaining PA gains across 24 months. It also examines if increases in PA differed by baseline PA.

STUDY DESIGN

The researchers conducted a superiority randomized controlled trial (data collected 2018-2022, analyzed 2023).

SETTING/PARTICIPANTS

Participants were 195 Spanish-speaking Latinas ages 18-65 in the Providence, RI area.

INTERVENTION

The original intervention is an empirically supported Spanish-language, individually-tailored, website-delivered PA intervention. The enhanced intervention includes text messaging and additional data-driven content and interactive features.

MAIN OUTCOME MEASURES

Total weekly minutes of moderate to vigorous PA (MVPA) was measured via accelerometry and self-report at 6, 12, 18, and 24 months.

RESULTS

Participants in both groups increased their MVPA over 24 months. There were no significant between-group differences at 6 or 12 months; at 18 months the enhanced intervention group had higher levels of self-reported (mean (sd): 90.35 (43.55) vs 70.18 [9.99]) and accelerometer-measured (66.21 [18.26] vs 60.27 [16.00]) MVPA compared to the original intervention group. They also had higher levels of self-reported (111.17 [23.35] vs 81.44 [1.82]) and accelerometer-measured (63.76 [15.12] vs 54.86 [14.59]) MVPA at 24 months. Baseline PA moderated the intervention effect.

CONCLUSIONS

This study demonstrates the potential to enhance the efficacy of website-based PA interventions by utilizing text messaging, and adding more interactive features, content, and phone support. These enhancements may be particularly beneficial in supporting long-term PA maintenance.

TRIAL REGISTRATION

This study is registered at www.

CLINICALTRIAL

gov (NCT03491592).

Improving Relational Functioning in Mother-Daughter Dyads With Obesity

Family-level interventions have the potential to address intergenerational obesity among Mexican American women. Given that poor family functioning is associated with worse weight loss outcomes, this study tested a weight management program aimed at improving relational functioning in mothers and daughters with obesity. Mexican American mothers and their adult daughters were randomly assigned to participate in a 16-week group-based standard behavioral (SB) weight loss program without or with relationship skills training (SRT). Relational functioning was assessed via observational behavioral coding using the Global Structural Family Rating Scale. General relational functioning and specifically positive alliance patterns and conflict avoidance improved significantly more in the SRT group than in the SB group. Average weight changes included percent weight loss of -5.6% in the SRT group versus -3.9% in the SB group and body mass index reduction of -2.2 kg/m2 in the SRT group versus -1.2 kg/m2 in the SB group. More participants in the SRT group (75%) than in the SB group (40%) tended to achieve at least 3% weight loss. Greater changes in positive alliance patterns increased the likelihood of losing 3% of body weight. Improving relational functioning in mother-daughter dyads may promote favorable outcomes in a behavioral weight loss intervention.

Increases in Muscle-Strengthening Activities Among Latinas in Seamos Saludables

BACKGROUND

Only 17% of Latinas meet national physical activity (PA) guidelines for both moderate-to-vigorous aerobic and muscle-strengthening PA. Additional health benefits are derived from the combination of aerobic and muscle-strengthening PA (vs. aerobic alone), yet there is paucity in research on muscle-strengthening activity in Latinas. The aim of this study was to examine changes in muscle-strengthening activity from baseline to 6 and 12 months in Seamos Saludables, a 12-month PA randomized controlled trial for Latinas.

METHODS

A secondary data analysis was conducted among 131 Latinas ages 18-65 years, who were randomized to either a PA Intervention or a Wellness Control. Self-reported muscle-strengthening exercise was measured at baseline, 6 months, and 12 months via adapted muscle-strengthening questions from the Behavioral Risk Factor Surveillance System.

RESULTS

There was a 16-minute/week difference in median minute/week of muscle-strengthening activity between Intervention and Wellness at 6 months (SE = 7.91, p = .04) and 45-minute/week difference at 12 months (SE = 25.80, p = .06) adjusting for baseline. Significantly more PA Intervention participants met muscle-strengthening guidelines of 2 or more days/week at 6 months versus Wellness Control participants (odds ratio [OR] = 4.29, 95% confidence interval [CI] = [1.03, 17.84]).

CONCLUSION

Results from the current study showed that Latinas engaged in muscle-strengthening activity in an intervention that emphasized primarily aerobic PA outcomes, suggesting they may be interested in engaging in muscle-strengthening activities. Future interventions targeting both aerobic and muscle-strengthening activity could achieve greater health improvements and help more Latinas reach the full national PA guidelines.ClinicalTrials.gov Identifier. NCT01583140.

Acculturation, Communication Competence, and Family Functioning in Mexican-American Mother-Daughter Dyads

Little is known of how intergenerational acculturation discrepancy relates to communication skills differences that may influence relationship quality among parents and adult children. Mexican-American mother-daughter dyads (n = 59) were studied using the Actor Partner Interdependence Model to examine dyadic associations of acculturation and communication competence with family functioning and mediation analysis to determine the indirect effect of acculturation discrepancy on family functioning through communication competence differences. Communication competence of mothers exerted significant actor and partner effects on daughter-perceived cohesion and closeness. Higher acculturation discrepancy predicted greater communication competence difference which in turn was associated with lower cohesion and closeness. There was a significant indirect effect of acculturation discrepancy on daughter-perceived cohesion through communication competence difference. Communication competence of mothers impacts their own as well as their daughters' perceptions of dyad cohesion and closeness. Intergenerational discrepant acculturation contributes to discordant communication skills that impair family functioning, which has implications for psychological well-being.

Individual and Family Factors in Disordered Eating Patterns of Mexican-American Women

OBJECTIVE

In this study, we examined the contribution of individual- (acculturation, body mass index, and body size satisfaction) and family- (maternal weight-related messages and disordered eating patterns) level factors in predicting bulimic and dieting behaviors in young Mexican-American women with overweight or obesity.

METHODS

We recruited adult Mexican- American mother-daughter dyads from the community. We conducted correlational analysis and hierarchical regression.

RESULTS

Daughters who were less satisfied with their body size reported higher symptoms of bulimic (r = -.34, p < .01) or dieting behavior (r = -.36, p < .01). Daughters who received more positive maternal messages on eating and weight had mothers with lower symptoms of bulimic (r = -.43, p < .01) or dieting behavior (r = -.30, p < .05). Maternal symptoms of bulimic behavior were the strongest predictor of daughters' bulimic behavior (ß = .379, p = .007), and body size satisfaction was the strongest predictor of daughters' dieting behavior (ß = -.372, p = .008) in adjusted models.

CONCLUSION

Mexican-American women who are less satisfied with their body size and have mothers with elevated symptoms of bulimic behavior are at risk for disordered eating patterns. Intervening at the individual level on body image and family level on maternal modeling of eating behavior may help support healthy weight management behaviors.

Assessing Maternal Support for Physical Activity in Latina Adolescents

Objectives: We developed a comprehensive measure to evaluate 11 domains of maternal social support for physical activity (PA) among Latina adolescents. Methods: The 26-item questionnaire included a version for mothers to rate how often they engaged in behaviors supporting their daughters' PA, and a version for daughters to rate how often their mothers engaged in the same behaviors. Bivariate correlations examined associations between mother-daughter perceived support for daughter's moderate-to-vigorous PA (MVPA), and associations between daughter's perceived support for PA and current MVPA. Results: Twenty-one Latina adolescents, which included 20 adolescent-mother dyads, enrolled in the study. Mother-daughter ratings of support showed significant positive correlations for reminders (r = .573, p = .01), watching daughters' sports (r = .566, p = .01), limit-setting (r = .564, p = .01), encouragement (r = .561, p = .01), transportation (r = .544, p = .02). We found statistically significant associations between MVPA and daughters' ratings of their mothers valuing (r = .544, p = .02) and facilitating PA (r = .48, p = .05). Conclusions: Mothers accurately perceive several supportive behaviors for PA given to daughters, but only daughters' perception of received support predicts their MVPA.

Psychometrics of the self-efficacy for physical activity scale among a Latina women sample

Background

Even though Latinos have become a priority population for the promotion of physical activity in the United States, several widely used scales in physical activity promotion research have not been validated among this population, particularly in Spanish. This study aims to assess the validity and other psychometrics of the Self-Efficacy for Physical Activity scale among a sample of Spanish-speaking Latina women who participated in the Pasos Hacia La Salud intervention. We also explored alternatives for scale simplification.

Methods

Data from 205 women corresponding to baseline, 6-month, and 12-month time points were analyzed. Internal consistency was assessed. A series of Spearman correlations, t-tests, linear regressions, and logistic regressions were used to assess the concurrent and predictive validity of the Self Efficacy for Physical Activity scale against both self-report and accelerometer-measured physical activity, using both continuous and categorical outcome data. Item Response Theory and factor analysis methods were used to explore alternatives to simplify the scale. Psychometric tests were repeated with the simplified scale.

Results

Cronbach’s alpha for the original scale was .72, .76, and .78 for baseline, 6-month, and 12-month data respectively. All concurrent validity tests conducted with 6-month and 12-month data, but not with baseline data, were statistically significant. Self-efficacy at 6 months was also predictive of physical activity at 12 months for all tests except one. Based on plots of Option Characteristic Curves, a modified version of the scale was created. Psychometric results of the modified scale were similar to those of the original scale.

Conclusions

This study confirmed the scale’s reliability and validity, and revealed that the scale’s accuracy improves when some response items are collapsed, which is an important finding for future research among populations with low literacy levels.

Egocentric networks and physical activity outcomes in Latinas

OBJECTIVE

Despite data linking the social environment to physical inactivity in Latinas, research on social network predictors of physical activity (PA) is limited. This study examined social network predictors of PA change in Latinas.

METHODS

Egocentric network data were collected from 102 adult Latinas (egos) participating in a randomized controlled PA intervention trial for underactive women. Moderate-to-vigorous PA (MVPA) was measured in minutes per week using the 7-Day PA Recall Interview and accelerometers at baseline and 12 months. Analyses characterized social network structure, composition, tie strength, homogeneity, and support for PA and determined the relationship between network characteristics and PA outcomes.

RESULTS

Networks had an average of four social ties (alters). Networks were high in density and transitivity and low in components, indicating high cohesion. Networks were primarily composed of females, Latinos, Spanish-speakers, and family members. Relationship ties were strong as evidenced by close living proximity, in-person contact, high emotional closeness, and long relationship duration. There was high homogeneity in demographics and PA behaviors. Multivariate analyses revealed that network size, familial ties, contact frequency, and ego-alter dissimilarities in age and running but similarities in walking, were associated with increased MVPA. Networks high in support for PA in the form of complimenting ego on exercise, taking over chores to allow ego to exercise, and co-participating with ego in exercise were also associated with greater MVPA.

CONCLUSION

These findings contribute to better understanding interpersonal processes that may influence behavior change in a group with especially low levels of PA.

Rationale and study protocol for Unidas por la Vida (United for Life): A dyadic weight-loss intervention for high-risk Latina mothers and their adult daughters

BACKGROUND

Half of Mexican-American women are under-active and nearly 78% are overweight/obese. The high lifetime risk of developing type 2 diabetes necessitates a culturally appropriate lifestyle intervention.

PURPOSE

Unidas por la Vida is a novel dyadic intervention that capitalizes on the centrality of family in Latino culture to mobilize an existing family dyad as a resource for health behavior change. The intervention aims to improve health behaviors and promote weight loss in two at-risk members of the same family: mothers with type 2 diabetes and their overweight/obese adult daughters who are at risk for developing diabetes.

METHODS

Participants (N = 460 mother-adult daughter dyads) will be randomized into one of three conditions: 1) dyadic participation (mothers-daughters) in a lifestyle intervention; 2) individual participation (mothers alone; unrelated daughters alone) in a lifestyle intervention; and 3) mother-daughter dyads in a minimal intervention control group.

RESULTS

The primary outcome is weight loss. Secondary outcomes include physical activity, dietary intake, physiological measures (e.g. HbA1c), and body composition. Both the dyadic and individual interventions are expected to produce greater weight loss at 6, 12, and 18 months than those in minimal intervention control group, with women assigned to the dyadic intervention expected to lose more weight and to maintain the weight loss longer than women assigned to the individual intervention.

CONCLUSION

Because health risks are often shared by multiple members of at-risk families, culturally appropriate, dyadic interventions have the potential to increase the success of behavior change efforts and to extend their reach to multiple family members.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02741037.

Weight and weight control behaviors of Latinas and their social ties

OBJECTIVE

Shared behaviors have been implicated in the clustering of obesity among socially connected people. This study determined how weight and weight control behaviors of participants and their social ties are related and how these factors are associated with weight change in participants.

METHOD

Adult Latinas participating in a lifestyle intervention completed an egocentric network measure of weight and weight control behaviors. Participant weight was objectively measured at baseline and 12 months. Multivariable regression models determined the relationship between weight and weight control behaviors of participants and their social ties.

RESULTS

Participants and their social ties shared similarities in weight control behaviors and weight change. Participants who reported social ties that had lost weight were more likely to eat small portions and low-fat foods, but those with social ties that had gained weight were more likely to use herbal supplements. Participants who reported more social ties who exercised, drank liquid meal replacements, took herbal supplements, and self-weighed were more likely to lose weight whereas those with fewer social ties that exercised were more likely to gain weight. Weight loss and weight gain by social ties predicted participant weight loss and weight gain, respectively.

CONCLUSIONS

Given that weight and weight control behaviors of Latinas reflect that of their social ties, targeting existing social networks for lifestyle interventions may more effectively improve and sustain health-promoting behaviors and outcomes. (PsycINFO Database Record

Where Do Women Get Advice About Weight, Eating, and Physical Activity During Pregnancy?

BACKGROUND

Most women report not receiving information about gestational weight gain (GWG) from prenatal providers, but less is known about other sources of information and their potential impacts on GWG. The purpose of this study was to investigate sources of information about diet, physical activity, and weight control during pregnancy, and the impact of information sources on maternal GWG.

MATERIALS AND METHODS

Participants were 183 women with normal weight and 172 women with overweight/obesity who had enrolled in a prenatal lifestyle intervention trial. At 6 weeks postpartum, women were asked whether they had received information about "diet, physical activity, or weight control" from 12 sources uninvolved in the trial (e.g., physician, Internet, and friend) and, if received, the extent to which they followed the advice. Information sources were examined in relation to odds of exceeding Institute of Medicine (IOM) GWG guidelines based on measured weights.

RESULTS

Most women reported receiving information from a book (60.6%) or the Internet (58.3%). Advice from physicians, dietitians, or nurses was reported in 55.6%, 48.2%, and 33.9% of women, respectively. Reported receipt of information from physicians was associated with reduced Odds Ratio ([95% Confidence Interval] = 0.55 [0.35-0.88]; p = 0.01) of exceeding IOM GWG guidelines. Reported receipt of information from other sources was not related to GWG.

CONCLUSIONS

Books and the Internet were the most prevalent information sources reported for prenatal diet, physical activity, and weight control. However, of all sources, only physician provision of information was associated with reduced odds of excessive GWG.

Racial/Ethnic Differences in Weight-Loss Strategies among US Adults: National Health and Nutrition Examination Survey 2007-2012

BACKGROUND

Dieting, exercising, and seeking professional help have been associated with intentional weight loss among adults.

OBJECTIVE

This study examined the use of diet (eg, ate less, ate less fat, or switched to low-calorie foods), exercise, diet and exercise, and professional help (eg, weight-loss program or prescribed diet pills) for weight loss among non-Hispanic whites, Mexican Americans, and non-Hispanic blacks.

DESIGN

Cross-sectional data from the 2007-2012 National Health and Nutrition Examination Survey were used.

PARTICIPANTS

Males and females (n=9,046) aged 20 to 65 years were included.

MAIN OUTCOME MEASURE

The weight history questionnaire assessed weight-loss attempts and use of weight-loss strategies in the past year.

STATISTICAL ANALYSES PERFORMED

Multivariate logistic regression models were used to estimate associations of race/ethnicity with strategies to lose weight. Models controlled for age, sex, education, and body mass index. In fully adjusted models, interactions of race/ethnicity by sex were tested.

RESULTS

Lower proportions of Mexican Americans (35%) and non-Hispanic blacks (35%) than non-Hispanic whites (39%) reported trying to lose weight. Among those who tried to lose weight, non-Hispanic blacks were less likely than non-Hispanic whites to use diet (odds ratio [OR] 0.78, 95% CI 0.67 to 0.90) or exercise (OR 0.83, 95% CI 0.70 to 0.99) for weight loss. Mexican Americans (OR 0.71, 95% CI 0.53 to 0.95) and non-Hispanic blacks (OR 0.71, 95% CI 0.52 to 0.95) were also less likely than non-Hispanic whites to use professional help for weight loss. The relationships between race/ethnicity and weight-loss strategy were stronger for females than males.

CONCLUSIONS

Targeted efforts are needed to address racial/ethnic disparities in weight-loss attempts and use of recommended strategies especially among females.

Social support and physical activity change in Latinas: Results from the Seamos Saludables trial

OBJECTIVE

Family responsibilities and poor social support are barriers to physical activity among Latinas. This study evaluated the effects of a home- and print-based intervention on social support, moderating effects of familial ties on support and moderate-to-vigorous physical activity (MVPA), and mediating effects of support on MVPA.

METHOD

Participants were randomized to receive through the mail either individually tailored physical activity intervention or general wellness print materials. Familial ties and social support were assessed by marital and child status and the social support for physical activity measure, respectively. MVPA was measured using the 7-day Physical Activity Recall Interview and accelerometer. Assessments were conducted at baseline, 6 months posttreatment, and 12 months follow-up.

RESULTS

Participants (n = 266; 40.6 ± 9.9 years old) were mostly immigrant and Spanish-speaking Latinas. The intervention group achieved greater increases in family and friend support compared to the wellness control group from baseline to posttreatment and follow-up (p < .05). Intervention changes in support did not depend on marital or child status. The intervention also increased minutes per week of MVPA more than the wellness control (p < .05) and the effect did not depend on marital or child status. There were significant indirect effects of treatment, indicating the intervention achieved greater increases in MVPA by increasing family (ab = 5.21, SE = 2.94, 95% confidence interval [CI] = 0.91-14.11) and friend (ab = 6.83, SE = 5.15, 95% CI = 0.16-20.56) support.

CONCLUSIONS

The intervention improved and sustained support from family and friends and MVPA irrespective of familial ties. Social support mediated increases in MVPA. (PsycINFO Database Record

Latino Civic Group Participation, Social Networks, and Physical Activity

OBJECTIVES

We examined whether social networks and resource awareness for physical activity may mediate the relationship between civic group participation and physical activity.

METHODS

This is a cross-sectional study of a randomly selected sample of 335 Latinos (mean age 42.1 ± 16.4 years) participating in the San Diego Prevention Research Center's 2009 Household Community Survey. Serial multiple mediation analysis tested the hypothesis that civic group participation is associated with meeting physical activity recommendations through an indirect mechanism of larger social networks followed by greater knowledge of physical activity community resources.

RESULTS

The indirect effects of level of civic group participation as well as religious, health, neighborhood, or arts group participation on meeting national physical activity recommendations were significant in models testing pathways through social network size and physical activity resource awareness. The direct effect was only significant for health group indicating that participating in a health group predicted physical activity independent of social network size and awareness of physical activity resources.

CONCLUSION

Belonging to civic groups may promote physical activity engagement through social network diffusion of information on community physical activity resources which has implications for health.

Pasos Hacia La Salud: a randomized controlled trial of an internet-delivered physical activity intervention for Latinas

Background

Internet access has grown markedly in Latinos during the past decade. However, there have been no Internet-based physical activity interventions designed for Latinos, despite large disparities in lifestyle-related conditions, such as obesity and diabetes, particularly in Latina women. The current study tested the efficacy of a 6-month culturally adapted, individually tailored, Spanish-language Internet-based physical activity intervention.

Methods

Inactive Latinas (N = 205) were randomly assigned to the Tailored Physical Activity Internet Intervention or the Wellness Contact Control Internet Group. Participants in both groups received emails on a tapered schedule over 6 months to alert them to new content on the website. The primary outcome was minutes/week of moderate to vigorous physical activity (MVPA) at 6 months as measured by the 7-Day Physical Activity Recall; activity was also measured by accelerometers. Data were collected between 2011 and 2014 and analyzed in 2015 at the University of California, San Diego.

Results

Increases in minutes/week of MVPA were significantly greater in the Intervention Group compared to the Control Group (mean difference = 50.00, SE = 9.5, p < 0.01). Increases in objectively measured MVPA were also significantly larger in the Intervention Group (mean differences = 31.0, SE = 10.7, p < .01). The Intervention Group was also significantly more likely to meet national physical activity guidelines at 6 months (OR = 3.12, 95 % CI 1.46–6.66, p < .05).

Conclusion

Findings from the current study suggest that this Internet-delivered individually tailored intervention successfully increased MVPA in Latinas compared to a Wellness Contact Control Internet Group.

Trial registration

NCT01834287.

Adapting Technological Interventions to Meet the Needs of Priority Populations

Cardiovascular diseases (CVD) comprise the leading cause of mortality worldwide, accounting for 3 in 10 deaths. Individuals with certain risk factors, including tobacco use, obesity, low levels of physical activity, type 2 diabetes mellitus, racial/ethnic minority status and low socioeconomic status, experience higher rates of CVD and are, therefore, considered priority populations. Technological devices such as computers and smartphones are now routinely utilized in research studies aiming to prevent CVD and its risk factors, and they are also rampant in the public and private health sectors. Traditional health behavior interventions targeting these risk factors have been adapted for technology-based approaches. This review provides an overview of technology-based interventions conducted in these priority populations as well as the challenges and gaps to be addressed in future research. Researchers currently possess tremendous opportunities to engage in technology-based implementation and dissemination science to help spread evidence-based programs focusing on CVD risk factors in these and other priority populations.

The relationship of social support with treatment adherence and weight loss in Latinos with type 2 diabetes

OBJECTIVE

Little is known about the effects of social support on weight loss in Latinos. This study determined whether sex moderated and treatment adherence mediated the association between social support and weight loss.

METHODS

Data from 278 Latino males and females with type 2 diabetes in the Intensive Lifestyle Intervention of the Look AHEAD trial were analyzed. Multivariable modeling tested for moderation and parallel multiple mediator modeling simultaneously tested the mediating effects of adherence to physical activity, diet, and session attendance on the relationship between baseline social support and percent weight loss at 1 year.

RESULTS

Social support for physical activity (having family and friends join in physical activity) was related to weight loss. Adherence to physical activity was related to both social support for physical activity and weight loss. Sex did not moderate these relationships. Adherence to physical activity completely mediated the relationship between social support for physical activity and weight loss.

CONCLUSIONS

Increasing companionship for physical activity may be an effective intervention strategy to promote behaviors important for weight loss among Latinos.

Content and perception of weight-related maternal messages communicated to adult daughters

PURPOSE

This study examined communication between mothers and overweight daughters on weight or weight-related behaviors through the perspective of adult daughters.

METHODS

Qualitative thematic analysis was used to analyze in-depth individual interviews conducted with 15 adult daughters.

RESULTS

Mothers who actively engaged in weight management behaviors, such as dieting and exercising regularly, transmitted these behaviors through modeling and served as continuous sources of verbal guidance on the topic. Weight management was discussed frequently and explicitly. Daughters relied on mothers for motivation in the form of supportive statements consisting of specific recommendations on weight management practices, encouragement to attempt or continue weight management practices, empathy with the struggle of managing weight, and affirmation of practices conducive to weight management. Mothers who did not engage in weight management behaviors were not viewed as credible sources for advice on diet and exercise. Daughters did most of the advice giving and modeling on weight management behaviors. Weight management was discussed infrequently and cautiously. Daughters perceived weight-related messages from mothers as unsolicited and critical.

CONCLUSION

The results suggest that shared lifestyle goals among family members are important for facilitating supportive communication and engagement in health-promoting behaviors and have implications for family-based weight management interventions.

Using interactive Internet technology to promote physical activity in Latinas: Rationale, design, and baseline findings of Pasos Hacia La Salud

Internet-based interventions show promise as an effective channel for promoting physical activity. However, a paucity of research has been conducted among underserved groups despite recent increases in Internet access and physical activity-related health disparities in these communities. Thus, the current randomized controlled trial will test the efficacy of an individually tailored, Internet-based physical activity intervention for Latinas. This program was culturally and linguistically adapted for the target population through extensive formative research. Two hundred eighteen sedentary Latinas were randomly assigned to the Tailored Physical Activity Internet Intervention or the Wellness Contact Control Internet Group. The Physical Activity Internet Intervention, based on Social Cognitive Theory and the Transtheoretical Model, utilizes a website with features including self-monitoring, goal setting, discussion forum, links to online resources, individually tailored and motivation-matched physical activity feedback reports, and exercise tip sheets. Participants receive regular emails over the first 6months with a tapered dose during the second 6months (maintenance phase) to alert them to new content on the website. The main outcome is differences in minutes/week of moderate to vigorous physical activity at six months as measured by the 7-Day Physical Activity Recall and accelerometer data. High reach, low cost, culturally relevant Internet-based interventions that encourage physical activity among Latinas could help reduce health disparities and thus have a substantial positive impact on public health.

Twelve-month physical activity outcomes in Latinas in the Seamos Saludables trial

BACKGROUND

Physical activity interventions designed for Latinas have shown short-term behavior change, but longer-term change and maintenance is rarely measured.

PURPOSE

To assess physical activity change at 12 months, following 6-month tapered completion of an RCT of a physical activity intervention for Latinas.

METHODS

Two hundred sixty-six underactive (<60 minutes/week physical activity) Latinas were randomized to an individually tailored, culturally and linguistically adapted physical activity intervention, or a wellness contact control. Participants received the materials through the mail for 6 months, then received booster doses at 8, 10, and 12 months. Minutes per week of moderate to vigorous physical activity were measured by the 7-Day Physical Activity Recall interview at baseline and 6 and 12 months. Data were collected at Brown University between 2009 and 2013, and analyses were conducted in 2013.

RESULTS

At 12 months, increases in moderate to vigorous physical activity were significantly greater in the intervention than in the wellness group (mean difference=52 minutes/week, SE=9.38, p<0.01), with both groups showing slight increases in moderate to vigorous physical activity from 6 to 12 months. Intervention participants were also more likely to meet national moderate to vigorous physical activity guidelines (OR=3.14, p=0.01).

CONCLUSIONS

The intervention was more effective than the wellness control at 12 months, and physical activity increases from baseline to 6 months were maintained, suggesting the intervention may lead to sustainable behavior change.

TRIAL REGISTRATION

This study is registered at Clinicaltrials.gov NCT01583140.

Social network characteristics associated with health promoting behaviors among Latinos

OBJECTIVE

This study examined the relationship between social network characteristics and health promoting behaviors (having a routine medical check-up, consuming no alcohol, consuming no fast food, and meeting recommendations for leisure-time physical activity and sleep duration) among Latinos to identify potential targets for behavioral interventions.

METHOD

Personal network characteristics and health behavior data were collected from a community sample of 393 adult Latinos (73% women) in San Diego County, California. Network characteristics consisted of size and composition. Network size was calculated by the number of alters listed on a name generator questionnaire eliciting people with whom respondents discussed personal issues. Network composition variables were the proportion of Latinos, Spanish-speakers, females, family, and friends listed in the name generator. Additional network composition variables included marital status and the number of adults or children in the household.

RESULTS

Network members were predominately Latinos (95%), Spanish-speakers (80%), females (64%), and family (55%). In multivariate logistic regression analyses, gender moderated the relationship between network composition, but not size, and a health behavior. Married women were more likely to have had a routine medical check-up than married men. For both men and women, having a larger network was associated with meeting the recommendation for leisure-time physical activity.

CONCLUSION

Few social network characteristics were significantly associated with health promoting behaviors, suggesting a need to examine other aspects of social relationships that may influence health behaviors.

The Seamos Saludables study: A randomized controlled physical activity trial of Latinas

BACKGROUND

Latinas in the U.S. are less physically active than non-Latino white women and also report higher levels of diabetes, obesity, and other conditions related to inactivity. Interventions are needed to address disparities in this high-risk group.

PURPOSE

To evaluate the efficacy of a culturally adapted, Spanish-language, individually tailored, computer expert system-driven physical activity print-based intervention for adult Latinas.

DESIGN

RCT.

SETTING/PARTICIPANTS

Participants were 266 inactive adult Latinas who participated between 2009 and 2012.

INTERVENTION

Participants were randomized to one of two treatment arms: a 6-month tailored physical activity intervention condition or wellness contact control. For both conditions, print materials were delivered by mail.

MAIN OUTCOME MEASURES

The main outcome measure was change in weekly moderate-to-vigorous physical activity (MVPA) measured by the 7-Day Physical Activity Recall interview, which was administered at baseline and post-intervention (6 months). Participants also wore accelerometers for a week at baseline and follow-up. Analyses were conducted in 2013.

RESULTS

Increases in minutes/week of MVPA measured by the 7-Day PAR were significantly greater in the intervention group compared to the control group (mean difference=41.36, SE=7.93, p<0.01). This difference was corroborated by accelerometer readings (rho=0.44, p<0.01). Further, results indicate that intervention participants had greater increases in self-efficacy, cognitive processes, and behavioral processes at 3 months compared to control paricipants (p's<0.05).

CONCLUSIONS

The tailored Spanish-language intervention was effective in increasing MVPA among predominantly low-income, less-acculturated Latinas. Such print-based interventions are poised for widespread dissemination, and thus may help address health disparities.

Physical activity in Latinas: social and environmental influences

Latinas are the largest, fastest growing female ethnic minority group in the USA, and also report the lowest levels of physical activity. Following the framework of the social ecological model, this review examines unique social and environmental factors that influence physical activity in Latinas. Research shows that Latinas receive little social support for activity despite having large, close-knit social networks. Interventions incorporating social support components are generally efficacious. Latinas also face many environmental barriers, including crime, heat, traffic, lack of facilities and a fear of immigration enforcement, and there have been few attempts to address environmental barriers in Latino communities. Successful future interventions will need to consider unique social and environmental barriers affecting Latinas, and help Latinas learn to incorporate social networks into physical activity participation.

Impact of Baseline BMI upon the Success of Latina Participants Enrolled in a 6-Month Physical Activity Intervention

High rates of obesity in Latinas highlight the need to determine if physical activity interventions are equally effective across the body mass index (BMI) range. Thus, this study assessed how BMI impacts success of Spanish-speaking Latinas in a culturally and linguistically adapted theory-based physical activity intervention (N = 45). Longitudinal regression models tested the relationship between baseline BMI and outcomes. Overall, a trend for a negative association was found between baseline BMI and self-reported physical activity and theoretical constructs targeted by the intervention over time. For example, someone with a 25 kg/m(2) BMI would report, on average, 27.5 more minutes/week of activity compared to someone with a 30 kg/m(2) BMI at followup. Furthermore, higher baseline BMI was significantly associated with lower self-efficacy, behavioral and cognitive processes of change, and family social support over time. These findings suggest that participants with higher BMI may need additional intervention to promote physical activity.

A culturally adapted physical activity intervention for Latinas: a randomized controlled trial

BACKGROUND

In the U.S., Latinos report particularly high levels of inactivity and related chronic illnesses and are in need of intervention. Thus, the purpose of the current study was to culturally and linguistically adapt an empirically supported, individually tailored physical activity print intervention for Latinos and then conduct an RCT of the modified program.

DESIGN

An RCT was conducted.

SETTING/PARTICIPANTS

The sample included 93 overweight/obese (80%) Latinas with low income and acculturation.

INTERVENTION

Data were collected in 2007-2008 and analyzed by intent-to-treat in 2009. Participants were randomly assigned to either (1) a culturally and linguistically adapted physical activity intervention (Seamos Activas) or (2) a wellness contact control condition.

MAIN OUTCOME MEASURES

Self-report physical activity, as measured pre- and post-intervention (6 months, 87% retention) by the 7-Day Physical Activity Recall.

RESULTS

Moderate-intensity (or greater) physical activity increased from an average of 16.56 minutes/week (SD=25.76) at baseline to 147.27 (SD=241.55) at 6 months in the intervention arm (n=45), and from 11.88 minutes/week (SD=21.99) to 96.79 (SD=118.49) in the wellness contact control arm (n=48). No between-group differences were seen in overall physical activity. Intervention participants reported significantly greater increases in cognitive (F[1, 91]=9.53, p=0.003) and behavioral processes of change (F[1, 91]=8.37, p=0.005) and available physical activity supplies and equipment at home (F[1, 91]=4.17, p=0.04) than control participants.

CONCLUSIONS

Results supported the hypothesized feasibility, acceptability, and preliminary efficacy of individually tailored physical activity print interventions among Latinas. Although more research is needed to corroborate these findings, such high-reach, low-cost approaches have great potential to positively affect public health.

TRIAL REGISTRATION

NCT00724165.

Health Promotion in Latinos

This article provides a review of health promotion research conducted among Latinos. The authors examined 31 intervention studies promoting physical activity and/or healthy diet in Latino samples. Overall, findings suggested that Latinos are responsive to interventions promoting physical activity and healthy diet, despite facing numerous barriers to health promotion. In fact, 12 of the 21 studies that measured physical activity and 19 of the 26 studies that measured dietary behavior reported that the intervention produced significant improvements in those health behaviors. Design strengths of these studies included the high rates of retention and large number of randomized controlled trials. However, there were concerns regarding the lack of diversity in the samples (mostly Mexican American women), limiting the generalizability of the findings and the underutilization of objective measures of physical activity and diet behavior in intervention studies.

Soluble adenylyl cyclase is required for activation of sperm but does not have a direct effect on hyperactivation

Soluble adenylyl cyclase (SACY) is an essential component of cAMP-signalling cascades that activate sperm motility and capacitate sperm. SACY activity is stimulated by HCO(3)(-) and Ca(2+). Sperm from Sacy(-/-) (null) mice were immotile or weakly motile, but cAMP analogues N(6),2'-O-dibutyryladenosine 3',5'-cyclic monophosphate (dbcAMP) and adenosine 3',5'-cyclic monophosphate acetoxymethyl ester (cAMP-AM) activated motility. Null sperm activated by dbcAMP quickly developed hairpin bends at the junction of the midpiece and principal piece, which could be prevented by omitting HCO(3)(-). Treating Sacy(-/-) sperm with thimerosal or NH(4)Cl to raise flagellar cytoplasmic Ca(2+) could not substitute for cAMP analogues in activating motility; however, sperm activated with cAMP-AM hyperactivated after thimerosal treatment. Treating activated wild-type sperm with SACY inhibitor KH7 did not prevent hyperactivation from developing during capacitation in vitro, although high doses impaired motility. These results indicate that, while the SACY/cAMP signalling pathway is required for motility activation, it is not directly involved in triggering hyperactivation.

Behavioral aspects of weight loss in type 2 diabetes

Recent research has clearly shown that lifestyle intervention can reduce the risk of diabetes in those with impaired glucose tolerance; weight reduction appears to be the primary determinant of this effect. Weight loss can also improve glycemic control and cardiovascular risk factors in those with diabetes; however, the long-term impact of weight loss on cardiovascular morbidity and mortality is still under investigation. An important finding is that modest weight losses of just 5% to 10% of initial body weight appear sufficient to produce these benefits for diabetes prevention and cardiovascular risk reduction.

Sperm Motility Defects and Infertility in Male Mice with a Mutation in Nsun7, a Member of the Sun Domain-Containing Family of Putative RNA Methyltransferases1

Poor sperm quality is the major cause of infertility in humans. Other than sex-linked factors, the genetic basis for male infertility is poorly defined, largely due to practical difficulties in studying the inheritance of this trait in humans. As an alternative, we have conducted forward genetic screens in mice to generate relevant models. We report on the identification and characterization of a chemically-induced mutation, Ste5Jcs1, which causes affected male mice to be sterile or subfertile. Mutant sperm exhibited depressed progressive motility associated with a rigid flagellar midpiece (but not principal piece) segment, which could not be rescued by treatment with agents that stimulate cAMP or calcium signaling pathways. Overall mutant sperm ultrastructure appeared normal, including the axoneme, although the midpiece mitochondrial sheath showed abnormal electron density patterns. Positional cloning of Ste5Jcs1 led to the identification of a mutation in a novel gene called Nsun7, which encodes a protein with a Sun domain that is homologous to tRNA and rRNA cytosine methyltransferases. Therefore, Ste5Jcs1 mutation uncovers a previously unrecognized biological process in sperm that underscores the functional compartmentalization of the midpiece and principal piece of the flagellum.

Bovine Sperm Hyperactivation Is Promoted by Alkaline-Stimulated Ca2+ Influx1

Sperm hyperactivated motility is characterized by high flagellar bend amplitude and asymmetrical beating, which are detected by computer-assisted sperm motility analysis as increased curvilinear velocity and lateral head movement. It is required for sperm penetration of the oocyte zona pellucida during fertilization and is induced by an increase in flagellar Ca(2+). Our objective was to determine whether pH plays a role in promoting Ca signaling of hyperactivated motility. The cell-permeant weak base NH(4)Cl increased curvilinear velocity and amplitude of lateral head movement of bovine sperm, indicative of hyperactivation. Fluorometric recordings of sperm loaded with BCECF-AM or fluo3-AM, revealed that NH(4)Cl evoked elevations of intracellular pH and Ca(2+), respectively, with the rise in pH occurring more rapidly than that of Ca(2+). Single-cell image analysis showed increased Ca(2+) levels in the flagellum in response to NH(4)Cl. When extracellular Ca(2+) was lowered with BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) prior to treatment with NH(4)Cl, intracellular pH was increased, but elevation of Ca(2+) and hyperactivation were diminished. This suggests that the rise in intracellular pH precedes an influx of Ca(2+). The Ca(2+) channel blocker Ni(2+) also diminished NH(4)Cl stimulation of hyperactivation, demonstrating that Ca(2+) entry is required for maximal expression of hyperactivation. Ca(2+) ionophore produced an increase in Ca(2+) that was 3-fold greater than that produced by NH(4)Cl; however, it produced a weaker hyperactivation response. These results indicate that a rise in pH increases intracellular Ca(2+)and promotes hyperactivation primarily by stimulating Ca(2+) influx, but also by other mechanisms.

Different regulatory systems operate in the midpiece and principal piece of the mammalian sperm flagellum

In mammalian sperm, the flagellar midpiece and principal piece contain different signalling molecules and ion channels. For example, the soluble adenylyl cyclase (sAC), which is required for activation of motility, is restricted to the midpiece, while the plasma membrane calcium channels CatSper1 and CatSper2, which are required for hyperactivation of motility, are restricted to the principal piece. The midpiece and principal piece are partially separated by a barrier called the annulus, yet despite this and the differential distribution of signalling molecules, they normally appear to work together to produce a wave that propagates smoothly down the tail. Under certain circumstances, however, the two segments can act independently. This is the case for sperm of Ste5Jcs l mutant mice, which swim with stiff midpieces but vigorously-beating principal pieces, due apparently to a defect in the mitochondria.

Contributions of extracellular and intracellular Ca2+ to regulation of sperm motility: Release of intracellular stores can hyperactivate CatSper1 and CatSper2 null sperm

In order to fertilize, mammalian sperm must hyperactivate. Hyperactivation is triggered by increased flagellar Ca(2+), which switches flagellar beating from a symmetrical to an asymmetrical pattern by increasing bending to one side. Thimerosal, which releases Ca(2+) from internal stores, induced hyperactivation in mouse sperm within seconds, even when extracellular Ca(2+) was buffered with BAPTA to approximately 30 nM. In sperm from CatSper1 or CatSper2 null mice, which lack functional flagellar alkaline-activated calcium currents, 50 microM thimerosal raised the flagellar bend amplitudes from abnormally low levels to normal pre-hyperactivated levels and, in 20-40% of sperm, induced hyperactivation. Addition of 1 mM Ni(2+) diminished the response. This suggests that intracellular Ca(2+) is abnormally low in the null sperm flagella. When intracellular Ca(2+) was reduced by BAPTA-AM in wild-type sperm, they exhibited flagellar beat patterns more closely resembling those of null sperm. Altogether, these results indicate that extracellular Ca(2+) is required to supplement store-released Ca(2+) to produce maximal and sustained hyperactivation and that CatSper1 and CatSper2 are key elements of the major Ca(2+) entry pathways that support not only hyperactivated motility but possibly also normal pre-hyperactivated motility.

The "soluble" adenylyl cyclase in sperm mediates multiple signaling events required for fertilization

Mammalian fertilization is dependent upon a series of bicarbonate-induced, cAMP-dependent processes sperm undergo as they "capacitate," i.e., acquire the ability to fertilize eggs. Male mice lacking the bicarbonate- and calcium-responsive soluble adenylyl cyclase (sAC), the predominant source of cAMP in male germ cells, are infertile, as the sperm are immotile. Membrane-permeable cAMP analogs are reported to rescue the motility defect, but we now show that these "rescued" null sperm were not hyperactive, displayed flagellar angulation, and remained unable to fertilize eggs in vitro. These deficits uncover a requirement for sAC during spermatogenesis and/or epididymal maturation and reveal limitations inherent in studying sAC function using knockout mice. To circumvent this restriction, we identified a specific sAC inhibitor that allowed temporal control over sAC activity. This inhibitor revealed that capacitation is defined by separable events: induction of protein tyrosine phosphorylation and motility are sAC dependent while acrosomal exocytosis is not dependent on sAC.

Different signaling pathways in bovine sperm regulate capacitation and hyperactivation

Hyperactivated sperm motility is characterized by high-amplitude and asymmetrical flagellar beating that assists sperm in penetrating the oocyte zona pellucida. Other functional changes in sperm, such as activation of motility and capacitation, involve cross talk between the cAMP/PKA and tyrosine kinase/phosphatase signaling pathways. Our objective was to determine the role of the cAMP/protein kinase A (PKA) signaling pathway in hyperactivation. Western blot analyses of detergent extracts of whole sperm and flagella were performed using antiphosphotyrosine antibody. Bull sperm capacitated by 10 microg/ml heparin and/or 1 mM dibutyryl-cAMP plus 100 microM 3-isobutyl-1-methylxanthine exhibited increased protein tyrosine phosphorylation without becoming hyperactivated. Procaine (5 mM) or caffeine (10 mM) immediately induced hyperactivation in nearly 100% of motile sperm but did not increase protein tyrosine phosphorylation. After 4 h of incubation with caffeine, sperm expressed capacitation-associated protein tyrosine phosphorylation but hyperactivation was significantly reduced. Sperm initially hyperactivated by procaine or caffeine remained hyperactivated for at least 4 h in the presence of Rp-cAMPS (cAMP antagonist) or PKA inhibitors H-89 or H-8. Pretreatment with inhibitors also failed to block induction of hyperactivation; however, the inhibitors did block protein tyrosine phosphorylation when sperm were incubated with capacitating agents, thereby verifying inhibition of the cAMP/PKA pathway. While induction of hyperactivation did not depend on cAMP/PKA, it did require extracellular Ca(2+). These findings indicate that hyperactivation is mediated by a Ca(2+) signaling pathway that is separate or divergent from the pathway associated with acquisition of acrosomal responsiveness and does not involve protein tyrosine phosphorylation downstream of the actions of procaine or caffeine.

A simplified method for measuring the thickness of glomerular basement membranes

Measurement of the thickness of glomerular basement membranes is required for the diagnosis of thin membrane nephropathy. Over the years various morphometric methods have been used but some are laborious so there is a need for establishing a simplified method for measuring thickness. In the present study 20 renal biopsies were used to carry out a comparative morphometric analysis between 2 methods. The first method was based on measuring thickness at the maximum number of available points, whereas for the second method, thickness was measured at only 5 points per loop. Since both methods gave mean values that are not statistically different in each patient, the authors recommend that the simplified method be used routinely for diagnosis.

Amyloid myopathy: evidence for mechanical injury to the sarcolemma

Myopathy is a rare clinical manifestation in primary systemic amyloidosis. The clinical phenotype and muscle histology are well described but the pathophysiological mechanisms remain poorly understood. We report a 40-year-old man who presented with hypertrophic cardiomyopathy and a limb girdle syndrome associated with deposition of amyloid and free lambda light chains in skeletal muscle. Electron microscopy showed amyloid fibrils, physically disrupting the plasma membrane and basal lamina, while laminin immunocytochemistry revealed a reduction of laminin beta1 and upregulation of laminin alpha1. We believe that one of the possible pathophysiological mechanisms in amyloid myopathy is mechanical disruption of the sarcolemma by the abutting amyloid fibrils.

[Availabilty of juveniles from natural sources of the oyster Pteria colymbus (Bivalvia: Mytilidae), in the Gulf of Cariaco, Venezuela]

We examined the spat availability the oyster Pteria colymbus at 6-8 and 19-21 m depths for 15 months (March 1993-June 1994) in Turpialito, Golfo de Cariaco, Venezuela. Spats were trapped using artificial collectors (plastic filaments in bags, 30 x 60 mm), suspended from a long line. Each collector was replaced by a replica monthly to analyse abundance, shell dimension and mass of P. colymbus. Intraweekly, the temperature, salinity, oxygen and food availability (Chlorophyll a, total seston, organic and inorganic seston) were determinated. There is juvenile recruitment all year, suggesting continuous reproduction. Spat counts were higher at 6-8 m (generally 50-230 juveniles per collector) with peaks in August and December 1993 (April and June 93 at 19-21 m). The length-weigh mass relation was higher at 19-21 m, suggesting greater food availability because of lower organism density (including P. colymbus) and a greater water flux. Phytoplanktonic abundance and temperature were correlated (r2=0.38) with juvenile abundanc; this relationship and the association of juvenile abundance with higher temperature and Chlorophyll a levels, suggest that spat abundance was higher at the beginning of the water stratification period, when phytoplankton biomass is high.

Thin glomerular basement membranes in patients with hematuria and minimal change disease

A detailed morphometric analysis of glomerular basement membrane (GBM) thickness was carried out on biopsies from 16 patients exhibiting normal histology and unremarkable immunofluorescence. Eleven of these patients presented with proteinuria, 8 in the nephrotic syndrome range, while 5 had hematuria as well. The remaining 5 patients presented with hematuria only. Eight patients had an initial diagnosis of minimal change disease, 4 were diagnosed as thin-membrane nephropathy, 2 had Alport syndrome, and the remaining 2 had hypertensive nephropathy. Quantitative morphometric analysis of GBM identified 3 subsets of patients. The first subset consisted of 6 patients: 5 adults, with an average GBM width of 361 +/- 34 nm, and 1 child. The second subset included 8 patients with thin GBMs and a mean thickness of 253 +/- 15 nm. The last subset comprised 2 patients with Alport syndrome showing marked variability in GBM thickness. This study has confirmed the presence of thin GBMs in hematurics, but has also revealed GBM thinning in 50% of patients with a diagnosis of minimal change disease.

Structure-activity analysis of the interaction of curacin A, the potent colchicine site antimitotic agent, with tubulin and effects of analogs on the growth of MCF-7 breast cancer cells

Originally purified as a major lipid component of a strain of the cyanobacterium Lyngbya majuscula isolated in Curaçao, curacin A is a potent inhibitor of cell growth and mitosis, binding rapidly and tightly at the colchicine site of tubulin. Because its molecular structure differs so greatly from that of colchicine and other colchicine site inhibitors, we prepared a series of curacin A analogs to determine the important structural features of the molecule. These modifications include reduction and E-to-Z transitions of the olefinic bonds in the 14-carbon side chain of the molecule; disruption of and configurational changes in the cyclopropyl moiety; disruption, oxidation, and configurational reversal in the thiazoline moiety; configurational reversal and substituent modifications at C13; and demethylation at C10. Inhibitory effects on tubulin assembly, the binding of colchicine to tubulin, and the growth of MCF-7 human breast carcinoma cells were examined. The most important portions of curacin A required for its interaction with tubulin seem to be the thiazoline ring and the side chain at least through C4, the portion of the side chain including the C9-C10 olefinic bond, and the C10 methyl group. Only two modifications totally eliminated the tubulin-drug interaction. The inactive compounds were a segment containing most of the side chain, including its two substituents, and analogs in which the methyl group at the C13 oxygen atom was replaced by a benzoate residue. Antiproliferative activity comparable with that observed with curacin A was only reproduced in compounds that were potent inhibitors of the binding of colchicine to tubulin. Molecular modeling and quantitative structure-activity relationship studies demonstrated that most active analogs overlapped extensively with curacin A but failed to provide an explanation for the apparent structural analogy between curacin A and colchicine.