Hypoaminoacidemia underpins glucagon-mediated energy expenditure and weight loss

Glucagon analogs show promise as components of next-generation, multi-target, anti-obesity therapeutics. The biology of chronic glucagon treatment, in particular, its ability to induce energy expenditure and weight loss, remains poorly understood. Using a long-acting glucagon analog, G108, we demonstrate that glucagon-mediated body weight loss is intrinsically linked to the hypoaminoacidemia associated with its known amino acid catabolic action. Mechanistic studies reveal an energy-consuming response to low plasma amino acids in G108-treated mice, prevented by dietary amino acid supplementation and mimicked by a rationally designed low amino acid diet. Therefore, low plasma amino acids are a pre-requisite for G108-mediated energy expenditure and weight loss. However, preventing hypoaminoacidemia with additional dietary protein does not affect the ability of G108 to improve glycemia or hepatic steatosis in obese mice. These studies provide a mechanism for glucagon-mediated weight loss and confirm the hepatic glucagon receptor as an attractive molecular target for metabolic disease therapeutics.

Striking the Balance: GLP-1/Glucagon Co-Agonism as a Treatment Strategy for Obesity

Obesity and Type 2 diabetes represent global health challenges, and there is an unmet need for long-lasting and effective pharmacotherapies. Although long-acting glucagon-like peptide-1 (GLP-1) analogues are now in routine use for diabetes and are now being utilised for obesity per se, the need for ever better treatments has driven the development of co-agonists, with the theoretical advantages of improved efficacy by targeting multiple pathways and reduced adverse effects. In this review, we highlight the past and present progress in our understanding and development of treatments based on GLP-1/glucagon co-agonism. We also reflect on the divergent effects of varying the GLP-1:glucagon activity and ratio in the context of pre-clinical and human clinical trial findings. In particular, the multiple metabolic actions of glucagon highlight the importance of understanding the contributions of individual hormone action to inform the safe, effective and tailored use of GLP-1/glucagon co-agonists to target weight loss and metabolic disease in the future.

Development of multidimensional scales to measure key leaders' perceptions of community capacity and organizational capacity for teen pregnancy prevention

This study discusses the development of scales to measure key leaders' self-reported involvement in community capacity building, perceptions of organizational capacity for teen pregnancy prevention, and the relationship between capacity and teen pregnancy rates. Data were collected from 1,516 key leaders across a rural southern state. Findings indicate that key leaders' perceptions of organizational capacity are related to their involvement in community capacity building efforts and community capacity is associated with teen pregnancy rates. This research represents progress toward measuring community and organizational capacity and may be used to inform future work focusing on developing quantitative measures of community capacity.

Real-time polymerase chain reaction quantification of the transgenes for roundup ready corn and roundup ready soybean in soil samples

A method for quantification of recombinant DNA for Roundup Ready (RR) corn and RR soybean in soil samples is described. Soil DNA from experimental field samples was extracted using a soil DNA extraction kit with a modified protocol. For the detection and quantification of recombinant DNA of RR corn and RR soybean, a molecular beacon and two pairs of specific primers were designed to differentially target recombinant DNA in these two genetically modified crops. Soil DNA extracts were spiked with RR corn or RR soybean DNA, and recombinant DNA was quantified using real-time PCR with a molecular beacon. As few as one copy of RR corn genome or one copy of RR soybean genome was detected in the soil DNA extract.

Extraction, detection and persistence of extracellular DNA in forest litter microcosms

A DNA extraction method was developed that preferentially extracted extracellular DNA rather than intracellular DNA from forest litter. The method purposely avoided the use of harsh chemicals and physical disruption steps used in total DNA extraction to release DNA from cells. The detection limit of PCR, determined by spiking forest litter samples with a dilution series of Choristoneura fumiferana MNPVegt(-)/lacZ(+) genomic DNA, was about 1 ng DNA or 6.85 x 10(6) target copies 0.5 g(-1) moist forest litter or 0.14 g(-1) dry forest litter. In this study, outdoor terrestrial microcosms, each spiked with 49.2 microg of genomic DNA (from the baculovirus CfMNPVegt(-)/lacZ(+)), were exposed to summer conditions. A 530 bp DNA fragment from the genome of the baculovirus CfMNPVegt(-)/lacZ(+) was detected in these microcosms for about 3 months. The DNA may have persisted for a longer period but was below the detection limit of the PCR analysis.

Effects of a replication of a multicomponent model for preventing adolescent pregnancy in three Kansas communities

CONTEXT

A significant amount of attention has been devoted to the complex issue of teenage pregnancy and to programs for reducing pregnancy among adolescents. Careful evaluations of such programs are needed to ascertain what strategies will be most effective at reducing teenage pregnancy.

METHODS

A pretest-posttest comparison group design was used to analyze the effects of a comprehensive multicomponent school and community intervention on estimated pregnancy rates and birthrates among young people in three Kansas communities: Geary County, Franklin County and selected neighborhoods of Wichita.

RESULTS

There were high levels of program activity in all three communities during the intervention period, including teacher training and sexuality education for students. Survey respondents rated highly such project interventions as the extension of school-linked clinic hours to accommodate student schedules and support groups established in middle schools. Between 1994 and 1997, the proportions of adolescents reporting that they had ever had sex decreased significantly among all ninth and 10th graders in Geary County, from 51% to 38% among females and from 63% to 43% among males. In Franklin County, more males in grades 11 and 12 reported using condoms in 1996 (55%) than had done so in 1994 (39%). Age at first intercourse remained relatively stable in Franklin and Geary counties during the intervention period. The estimated pregnancy rate among adolescents aged 14-17 decreased between 1994 and 1997 in Geary Country, while it increased in comparison areas. The estimated pregnancy rates among 14-17-year-olds decreased in both Franklin County and its comparison communities. The birthrate declined both in one target area of Wichita and in its comparison area from 1991-1993 to 1994-1996. Over the same time period, the birthrate increased in a second target area of Wichita, while it decreased in the comparison community.

CONCLUSIONS

This evaluation of a comprehensive multicomponent program for adolescent pregnancy prevention contributes to our understanding of this model and its replicability in diverse communities. Ongoing program evaluation is important for developing initiatives and for refining strategies so they respond to local conditions.

Support for school-based sexuality education among South Carolina voters

A random-digit dialed telephone survey was conducted in a traditionally conservative southern state to determine the level of support for sexuality education in the public schools including support for specific sexuality education topics, the earliest grade level at which each topic should be taught, and the amount of instruction time required for sexuality education in the high schools. Survey data were obtained from 534 South Carolina registered voters in late January/early February 1997. Results demonstrated that most South Carolina registered voters: 1) supported sexuality education in the public schools; 2) supported instruction on a variety of sexuality education topics; 3) supported instruction at all grade levels, especially beginning in middle school; and 4) believed instruction time for sexuality education in the high schools should either remain the same or be increased. In addition, a significant increase in support for sexuality education occurred from the beginning of the survey to the end, suggesting that the instrument itself may have served as an educational tool for respondents. The characteristics of registered voters who supported sexuality education at the beginning of the survey and at the end were examined and compared. These results may assist in the development of educational and marketing strategies designed to build support for school-based sexuality education programs in South Carolina and elsewhere.

Determinants of physical activity among female adolescents

INTRODUCTION

Women, and particularly African-American women, may be less physically active than what is ideal. Knowledge of factors that influence physical activity is valuable information to those planning and administering exercise promoting interventions.

METHODS

The associations of 25 variables with current global physical activity were assessed via regression analysis. Eight hundred and fifty-two young women, 14-18 years of age, were sampled. Each completed a 7-day recall of physical activity and an 83-item survey. The sample was further subdivided by ethnic group, and then ethnic group and age to ascertain whether determinants of physical activity differ across these groups.

RESULTS

Ethnic group (Caucasians more active) and age (younger more active) were significant influences on physical activity. Overall, nurture from biological fathers and participation in organized sports associated with physical activity. Viewing two or more hours of television per night negatively influenced physical activity. Among African-American girls (n = 626), participation in organized sports, friend support, and nurture from biological fathers significantly associated with physical activity. However, following sports through the media negatively influenced physical activity. Among Caucasians (n = 226), attitudes were the sole significant correlate of physical activity.

CONCLUSIONS

Those planning interventions targeting female adolescents should consider employing distinct strategies for specific ethnic group and age subgroups. Opportunities for physicians to have an impact on the physical activity of female adolescents includes using their community standing to influence school policies and to counsel female patients individually during office visits.

Correlates of aggressive and violent behaviors among public high school adolescents

PURPOSE

This study analyzed the types and predictors of violent behaviors reported by 4,137 South Carolina adolescents, grades nine through twelve.

METHODS

The 70 item self-report Youth Risk Behavior Survey developed and piloted by the Centers for Disease Control and Prevention was utilized in 57 of the state's public high schools. A series of logistic regression analyses were performed for each race/gender group to explore the relation of the demographic and potential risk variables to fighting and carrying weapons.

RESULTS

Results indicate that 38 percent of males and 11 percent of females reported carrying a weapon. Eleven percent of males and five percent of females reported fights resulting in an injury. The strongest predictors of fighting were binge drinking and sexual activity for males, any alcohol use and illegal drug use for white females, and sexual activity for black females. For carrying a weapon, the strongest predictors included alcohol use and sexual activity in all but white females, and illegal drug use among whites, but not blacks.

CONCLUSION

Prevention of adolescent violence calls for creative approaches in school and community settings and will require long-term intervention strategies, focused on adolescent behavior change and environmental modifications.

Correlates and consequences of early initiation of sexual intercourse

This cross-sectional analysis of the 1991 CDC Youth Risk Behavior Survey explored factors associated with an early age at first sexual intercourse. Almost 18% of White males, 49% of Black males, 5% of White females and 12% of Black females were sexually active before age 13. Carrying a weapon to school, fighting, and early (< age 13) experimentation with cigarettes and alcohol were associated with early initiation of sexual activity for all four race and gender groupings. Those initiating sexual activity early had greater numbers of partners but were 50% less likely to use condoms regularly and were two-seven times more likely to have been pregnant or caused a pregnancy. Females who initiated sexual activity early were more likely to have had a sexually transmitted disease (STD). Interventions to postpone sexual activity need to be tailored to the ethnic and gender differences observed in these analyses. Interventions must begin before age 13 and should be comprehensive school-based efforts.

Aggression, substance use, and suicidal behaviors in high school students

OBJECTIVES

We sought to analyze the frequency and correlates of suicidal behaviors in a community sample of adolescents.

METHODS

Information concerning suicidal thoughts and acts, aggressive behaviors, substance use and physical recklessness were collected with the 70-item self-report Youth Risk Behavior Survey from a statewide sample of 3764 South Carolina public high school students.

RESULTS

Seventy-five percent of students reported no suicidal behaviors, 11% reported serious suicidal thoughts, 6.4% reported specific suicidal plans, 5.9% reported attempts not requiring medical care, and 1.6% reported attempts requiring medical care. All types of suicidal behaviors occurred more frequently in females than males. Odds ratios for aggressive behaviors and cigarette use were elevated across all categories of suicide behaviors, increasing in magnitude with severity of reported suicidal behavior. Substance use was associated with some but not all categories of suicidal behaviors. The relationships were most pronounced with the use of potentially more dangerous drugs.

CONCLUSIONS

The results suggest that suicidal behaviors are not infrequent occurrences among adolescents and that they often coexist with other high-risk behaviors. Interventions designed to reduce suicidal behaviors should simultaneously address coexisting high-risk behaviors.

Correlates of condom use and number of sexual partners among high school adolescents

Factors associated with condom use and number of sexual partners were examined in a statewide sample of public high school students in grades 9-12 (N = 3,893). Data were collected in spring 1990 using the 70-item, self-report Youth Risk Behavior Survey, developed and piloted by the Centers for Disease Control. Composite scores were constructed to measure aggression, physical recklessness, alcohol use, illegal drug use, cigarette use, lack of exercise, and academic self-image. Since simple polychotomous logistic regression models revealed a significant race by gender interaction, multivariate models were run separately for each race-gender group. Odds ratios and 95% confidence intervals were calculated from polychotomous logistic regression of lifetime sexual activity and condom use with their potential correlates. Risky sexual behavior appears to be correlated with a complex of other behaviors that place students at risk. A pattern of declining condom use with increasing number of partners was evident, especially for White students.

Adolescent risk behaviors and the potential for violence: a look at what's coming to campus

This study analyzed the types and predictors of violent behaviors reported by students in Grades 11 and 12 in South Carolina. Results are based upon responses of 2,299 students from 57 schools, approximately 3% of the total state enrollment in those grades. The 70-item self-report Youth Risk Behavior Survey developed and piloted by the Federal Centers for Disease Control was used to collect data. The authors performed a series of logistic regression analyses to explore the relation of the demographic and potential risk variables to fighting and carrying weapons. Results from the simple logistic analyses, adjusting for race and gender, indicated that alcohol use, binge drinking, sexual activity, and use of any drugs were significantly associated (p < .05) with reported fighting. These variables and poor academic self-image were significantly associated with carrying weapons. Comprehensive multivariable models indicated that, when considered simultaneously, being black, male, sexually active, and engaging in binge drinking and drug use were significant predictors of fighting. Gender, but not race, alcohol use, drug use, or sexual activity, remained a significant predictor of carrying a weapon. Findings suggest that college risk-reduction and health-promotion programs should direct efforts at environmental modification, policy development and enforcement, as well as at personal change, including effective conflict resolution, stress management, and communication skills.

Reducing adolescent pregnancy through school and community-based education

The resident population of the western portion of a South Carolina county has undergone a public health information and education intervention since October 1982. The purpose of the intervention has been to reduce the occurrence of unintended pregnancies among unmarried adolescents. Intervention messages are targeted at parents, teachers, ministers and representatives of churches, community leaders, and children enrolled in the public school system. The messages emphasize development of decision-making and communication skills, self-esteem enhancement, and understanding human reproductive anatomy, physiology, and contraception. The estimated rate of pregnancy ([live births plus fetal deaths plus induced abortions] per 1000 female population) for females aged 14 to 17 years in the county's western portion has declined remarkably since the intervention began, and the changes are statistically significant when compared with three sociodemographically similar counties and also with the eastern portion of the county.

Folic acid uptake characteristics of a human colon carcinoma cell line, Caco-2. A newly-described cellular model for small intestinal epithelium

To investigate a newly described model for differentiated small intestinal function, folic acid uptake characteristics were examined in the human colon carcinoma cell line, Caco-2. Monolayers of this cell line spontaneously exhibit structural and functional differentiation patterns characteristic of mature enterocytes, with the appearance of brush border microvilli and high activity levels of the enzymes associated with the brush border. Our results concur with other models of folic acid uptake that emphasize the importance of intraluminal factors on micronutrient absorption. Folate uptake declined rapidly between pH 5.8 and 7.5, and was dependent on the initial folate concentration in the media. A dual uptake process is suggested, with a high rate of uptake at folate concentrations below 20 nmol/ml and linear uptake characteristics at higher concentrations.

Aldosterone in sustained essential hypertension

Plasma aldosterone (PA), plasma renin activity (PRA), extracellular fluid volume (EFV) and hepatic blood flow were measured in forty-four patients with sustained essential hypertension and compared with forty-two normotensive controls of same age and sex. All patient had inulin clearances within the normal range and balanced sodium intake and urinary output. In hypertensives, PA, PRA, EFV and hepatic blood flow were within normal ranges; the log-ratio PA:PRA was significantly elevated (P less than 0.001). In normotensives, a negative relationship was observed between PA and EFV (r=-0.55; P less than 0.001) while a positive relationship was observed between PA and PRA (=+0.70; P less than 0.001). In hypertensives, the two relationships were disrupted or less significant: for a given value of EFV, PA was more elevated in hypertensives than in normotensives; for a given value of PRA, PA was more evaluated in hypertensives than in normotensives. The results could not be explained on the basis of a disturbance in hepatic blood flow and/or in the metabolic clearance rate of aldosterone. The study provided evidence that, in patients with sustained essential hypertension and equilibrated sodium balance, there is an excess of plasma aldosterone relative to the levels of extracellular fluid volume and plasma renin activity. The excess of probably related to an abnormality in the adrenal secretion.

Relationship between renin and extracellular fluid volume in normotensive and hypertensive subjects

Plasma renin activity and extracellular fluid volume were determined in 34 normotensive and in 35 sustained essential hypertensive patients with normal renal function, balanced sodium intake and urinary output. In normotensives, plasma renin activity was negatively correlated to extracellular fluid volume (r = 0.54; p = 0.001). The 95% confidence limits of the normotensive curve was used as nomogram to classify the hypertensive patients into two groups: those (23 cases) that fell within the limits of the normal curve (group I) and those (12 cases) that were below these limits (group II). In comparison with group I, group II was characterized by: (i) similar values for age, blood pressure, inulin clearance and extracellular fluid volume and (ii) significantly but lower values (p less than 0.001) for plasma renin activity with maintenance of the relationship between extracellular fluid volume and renin. The study strongly suggests that (i) the hypertensives of group I had no abnormal regulation of the renin-angiotensin system in comparison with the control subjects and (ii) the hypertensives of group II had an extracellular fluid volume-renin relationship set for lower values of renin.