Report on the 2021 Aniridia North America symposium on PAX6, aniridia, and beyond

The inaugural Aniridia North America (ANA) Symposium was held on the first weekend in November 2021 in Charlottesville, VA, at the University of Virginia. The purpose of this meeting was to bring together an international group of scientists, physicians, patient advocacy groups, and individuals with aniridia to discuss recent advances in knowledge about aniridia and other congenital eye diseases and the development of potential treatments for congenital eye disorders using personalized medicine. Leaders in several areas of eye research and clinical treatment provided a broad perspective on new research advances that impact an understanding of the causes of the damage to the eye associated with aniridia and the development of novel treatments for this and related disorders. Here we summarize the research discussed at the symposium.

The synthetic liver X receptor agonist GW3965 reduces tissue factor production and inflammatory responses in human islets in vitro

AIMS/HYPOTHESIS

Optimising islet culture conditions may be one strategy for reducing islet loss prior to, and immediately after, islet transplantation. Liver X receptor (LXR) agonism has previously been shown to increase insulin release from pancreatic islets and reduce inflammation in leucocytes. Our aim was to investigate whether the synthetic LXR agonist GW3965 could modulate the inflammatory status of human pancreatic islets.

METHODS

Levels of pro-inflammatory cytokines and tissue factor in isolated human islets were determined by TaqMan low density array and/or real-time quantitative RT-PCR (mRNA levels) and enzyme immunoassay (EIA) (protein levels). Islet viability was measured using intracellular ATP content, ADP/ATP ratio, mitochondrial dehydrogenase activity (XTT assay) and insulin secretion in a dynamic glucose-challenge model. Apoptosis was determined by EIA measurement of histone-DNA complexes present in cytoplasm and by assaying caspase-3/-7 activity.

RESULTS

Treatment of LPS-stimulated human islets with the synthetic LXR agonist GW3965 (1 micromol/l) for 24 h reduced mRNA and protein levels of selected pro-inflammatory cytokines (IL-8, monocyte chemotactic protein-1 and tissue factor). Moreover, GW3965 had no adverse effect on insulin secretion, islet viability or apoptosis. No excess of lipid accumulation could be detected with the dosage and exposure time used.

CONCLUSIONS/INTERPRETATION

LXR activation suppresses inflammation in human islets in vitro without adverse effects on islet viability. Short-term moderate activation of LXR prior to islet transplantation may represent a possible strategy for improving post-transplant islet survival.

A novel technique for fascial fixation of laparoscopic adjustable gastric band ports

Access port dislodgement after laparoscopic adjustable gastric banding is a recurring problem that often requires operative revision. Securing the port to the abdominal wall fascia in the traditional way with standard instruments is challenging in obese patients due to a thick abdominal wall. Therefore, we have devised a novel and simple technique for access port fixation using the EndoStitch device.

Liver X receptor (LXR) regulation of the LXRalpha gene in human macrophages

The nuclear oxysterol receptors LXRalpha (NR1H3) and LXRbeta (NR1H2) coordinately regulate the expression of genes involved in the transport and catabolism of cholesterol. In macrophages, LXR stimulates the transcription of genes encoding transporters involved in cholesterol efflux, which may limit the transformation of these cells into foam cells in response to lipid loading. Here, we report that natural and synthetic LXR ligands induce the expression of the LXRalpha gene in primary human macrophages and differentiated THP-1 macrophages. This regulation was not observed in primary human adipocytes or hepatocytes, a human intestinal cell line, or in any mouse tissue or cell line examined. The human LXRalpha gene was isolated, and the transcription initiation site delineated. Analysis of the LXRalpha promoter revealed a functional LXR/RXR binding site approximately 2.9 kb upstream of the transcription initiation site. We conclude that LXRalpha regulates its own expression in human macrophages and that this response is likely to amplify the effects of oxysterols on reverse cholesterol transport. These findings underscore the importance of LXR as a potential therapeutic target for the treatment of atherosclerosis.

Structural determinants of ligand binding selectivity between the peroxisome proliferator-activated receptors

The peroxisome proliferator-activated receptors (PPARs) are transcriptional regulators of glucose, lipid, and cholesterol metabolism. We report the x-ray crystal structure of the ligand binding domain of PPAR alpha (NR1C1) as a complex with the agonist ligand GW409544 and a coactivator motif from the steroid receptor coactivator 1. Through comparison of the crystal structures of the ligand binding domains of the three human PPARs, we have identified molecular determinants of subtype selectivity. A single amino acid, which is tyrosine in PPAR alpha and histidine in PPAR gamma, imparts subtype selectivity for both thiazolidinedione and nonthiazolidinedione ligands. The availability of high-resolution cocrystal structures of the three PPAR subtypes will aid the design of drugs for the treatments of metabolic and cardiovascular diseases.

Autoregulation of the human liver X receptor alpha promoter

Previous work has implicated the nuclear receptors liver X receptor alpha (LXR alpha) and LXR beta in the regulation of macrophage gene expression in response to oxidized lipids. Macrophage lipid loading leads to ligand activation of LXRs and to induction of a pathway for cholesterol efflux involving the LXR target genes ABCA1 and apoE. We demonstrate here that autoregulation of the LXR alpha gene is an important component of this lipid-inducible efflux pathway in human macrophages. Oxidized low-density lipoprotein, oxysterols, and synthetic LXR ligands induce expression of LXR alpha mRNA in human monocyte-derived macrophages and human macrophage cell lines but not in murine peritoneal macrophages or cell lines. This is in contrast to peroxisome proliferator-activated receptor gamma (PPAR gamma)-specific ligands, which stimulate LXR alpha expression in both human and murine macrophages. We further demonstrate that LXR and PPAR gamma ligands cooperate to induce LXR alpha expression in human but not murine macrophages. Analysis of the human LXR alpha promoter led to the identification of multiple LXR response elements. Interestingly, the previously identified PPAR response element (PPRE) in the murine LXR alpha gene is not conserved in humans; however, a different PPRE is present in the human LXR 5'-flanking region. These results have implications for cholesterol metabolism in human macrophages and its potential to be regulated by synthetic LXR and/or PPAR gamma ligands. The ability of LXR alpha to regulate its own promoter is likely to be an integral part of the macrophage physiologic response to lipid loading.

Health issues in journalism and reporting

Journalists witness events and report the news. The gathering and presentation of this information may subject the journalist to a variety of physical and psychological hazards. Some health and safety risk factors are inherent within the profession: for example, stress associated with deadlines and reporting on events in dangerous climactic or social conditions. Survey data and information collected by professional journalism associations should be used to educate journalists and, whenever possible, to attenuate the risk factors. Some of the more common risks within the profession include those relating to travel, repetitive strain, and psychological stress.

Developmentally regulated cell cycle dependence of swelling-activated anion channel activity in the mouse embryo

Anion channels activated by increased cell volume are a nearly ubiquitous mechanism of cell volume regulation, including in early preimplantation mouse embryos. Here, we show that the swelling-activated anion current (ICl,swell) in early mouse embryos is cell-cycle dependent, and also that this dependence is developmentally regulated. ICl,swell is present both in first meiotic prophase (germinal vesicle stage) mouse oocytes and in unfertilized mature oocytes in second meiotic metaphase, and it persists after fertilization though the 1-cell and 2-cell stages. ICl,swell was found to remain unchanged during metaphase at the end of the 1-cell stage. However, ICl,swell decreased during prophase and became nearly undetectable upon entry into metaphase at the end of the 2-cell stage. Entry into prophase/metaphase was required for the decrease in ICl,swell at the end of the 2-cell stage, since it persisted indefinitely in 2-cell embryos arrested in late G2. There is considerable evidence that the channel underlying ICl,swell is not only permeable to inorganic anions, but to organic osmolytes as well. We found a similar pattern of cell cycle and developmental dependence in the 1-cell and 2-cell stages for the swelling-induced increase in permeability to the organic osmolyte glycine. Thus, entry into metaphase deactivates ICl,swell in embryos, but only after developmental progression through the 2-cell stage.

Catecholamines decrease nitric oxide production by cytokine-stimulated hepatocytes

BACKGROUND

Catecholamines are significantly elevated in inflammatory responses and play a regulatory role in sepsis. Nitric oxide (NO), also a key inflammatory mediator in sepsis, is produced in large amounts by the inducible nitric oxide synthase (iNOS) in the liver. The purpose of this study was to test the hypothesis that catecholamines play a role in the regulation of NO production by hepatocytes.

METHODS

Primary hepatocytes were isolated from healthy male Sprague-Dawley rats and either cultured with normal medium or stimulated with cytomix (interleukin-1 beta, interferon-gamma, and tumor necrosis factor-alpha) in the presence or absence of epinephrine or norepinephrine at varying concentrations. Total RNA was isolated 6 hours after treatment and analyzed by Northern blotting for iNOS mRNA. Protein extracts were obtained at 12 hours and were analyzed by Western immunoblotting for iNOS. Cell culture supernatants were analyzed for NO, determined as the stable end-product NO(2)(-), at 24 hours.

RESULTS

Epinephrine and norepinephrine significantly decreased NO(2)(-) levels in stimulated hepatocytes but had no effect on iNOS mRNA or protein levels. The decrease in NO(2)(-) was reproduced by the adenylate cyclase stimulator, forskolin. The catecholamine-induced decrease in NO(2)(-) was completely reversed by the protein kinase A inhibitor Rp-8-Br-cyclic adenosine monophosphate.

CONCLUSIONS

Catecholamines decrease hepatocyte production of NO in response to cytokine stimulation. This effect seems to be due to post-translational events and appears to be mediated in part by cyclic adenosine monophosphate.

The human nuclear xenobiotic receptor PXR: structural determinants of directed promiscuity

The human nuclear pregnane X receptor (hPXR) activates cytochrome P450-3A expression in response to a wide variety of xenobiotics and plays a critical role in mediating dangerous drug-drug interactions. We present the crystal structures of the ligand-binding domain of hPXR both alone and in complex with the cholesterol-lowering drug SR12813 at resolutions of 2.5 and 2.75 angstroms, respectively. The hydrophobic ligand-binding cavity of hPXR contains a small number of polar residues, permitting SR12813 to bind in three distinct orientations. The position and nature of these polar residues were found to be critical for establishing the precise pharmacologic activation profile of PXR. Our findings provide important insights into how hPXR detects xenobiotics and may prove useful in predicting and avoiding drug-drug interactions.

Recent trends in participation in physical education among US high school students

To examine recent trends in physical education (PE) enrollment, daily attendance in PE, and being physically active in PE among high school students in the United States, this study analyzed data from the 1991, 1993, 1995, and 1997 national school-based Youth Risk Behavior Surveys (n = 55,734). Logistic regression analyses were conducted to test for significant linear time trends among the total student population and demographic subgroups (gender, race/ethnicity, and grade). Although PE enrollment in the total student population did not change from 1991 (48.9%) to 1997 (48.8%), the prevalence of students who attended PE daily, and the prevalence of students who were physically active > 20 minutes in an average PE class both decreased significantly among nearly all demographic subgroups. The prevalence of students who were physically active > 20 minutes in daily PE classes decreased from 34.2% in 1991 to 21.7% in 1997 (p < 0.001). To reverse current trends, high schools should implement daily PE classes that emphasize participation in lifelong health-related physical activity for all students.

Pharmacophore analysis of the nuclear oxysterol receptor LXRalpha

A cell-free assay was developed for the orphan nuclear receptor LXRalpha that measures the ligand-dependent recruitment of a peptide from the steroid receptor coactivator 1 (SRC1) to the nuclear receptor. Using this ligand-sensing assay (LiSA), the structural requirements for activation of the receptor by oxysterols and related compounds were studied. The minimal pharmacophore for receptor activation was shown to be a sterol with a hydrogen bond acceptor at C24. 24(S),25-Epoxycholesterol (1), which meets this criterion, is among the most efficacious of the oxysterols and is an attractive candidate as the LXRalpha natural hormone. Cholenic acid dimethylamide (14) showed increased efficacy compared to 1, whereas the unnatural oxysterol 22(S)-hydroxycholesterol (4) was shown to be an antagonist of 1 in the LiSA. The structural requirements for SRC1 recruitment in the LiSA correlated with the transcriptional activity of compounds in a cell-based reporter assay employing LXRalpha-GAL4 chimeric receptors. Site-directed mutagenesis identified Trp(443) as an amino acid critical for activation of LXRalpha by oxysterol ligands. This information was combined with the structure-activity relationship developed from the LiSA to develop a 3D homology model of LXRalpha. This model may aid the design of synthetic drugs targeted at this transcriptional regulator of cholesterol homeostasis.

Surveillance for characteristics of health education among secondary schools--school health education profiles, 1998

PROBLEM/CONDITION

School health education (e.g., classroom instruction) is an essential component of school health programs; such education promotes the health of youth and improves overall public health.

REPORTING PERIOD

February-May 1998.

DESCRIPTION OF SYSTEM

The School Health Education Profiles monitor characteristics of health education in middle or junior high schools and senior high schools in the United States. The Profiles are school-based surveys conducted by state and local education agencies. This report summarizes results from 36 state surveys and 10 local surveys conducted among representative samples of school principals and lead health education teachers. The lead health education teacher coordinates health education policies and programs within a middle/junior high school or senior high school.

RESULTS

During the study period, most schools in states and cities that conducted Profiles required health education in grades 6-12. Of these, a median of 91.0% of schools in states and 86.2% of schools in cities taught a separate health education course. The median percentage of schools in each state and city that tried to increase student knowledge in selected topics (i.e., prevention of tobacco use, alcohol and other drug use, pregnancy, human immunodeficiency virus [HIV] infection, other sexually transmitted diseases, violence, or suicide; dietary behaviors and nutrition; and physical activity and fitness) was >73% for each of these topics. The median percentage of schools with a health education teacher who coordinated health education was 38.7% across states and 37.6% across cities. A median of 41.8% of schools across states and a median of 31.0% of schools across cities had a lead health education teacher with professional preparation in health and physical education, whereas a median of 6.0% of schools across states and a median of 5.5% of schools across cities had a lead health education teacher with professional preparation in health education only. A median of 19.3% of schools across states and 21.2% of schools across cities had a school health advisory council. The median percentage of schools with a written school or school district policy on HIV-infected students or school staff members was 69.7% across states and 84.4% across cities.

INTERPRETATION

Many middle/junior high schools and senior high schools require health education to help provide students with knowledge and skills needed for adoption of a healthy lifestyle. However, these schools might not be covering all important topic areas or skills sufficiently. The number of lead health education teachers who are academically prepared in health education and the number of schools with school health advisory councils needs to increase.

PUBLIC HEALTH ACTION

The Profiles data are used by state and local education officials to improve school health education.

Use of birth control pills, condoms, and withdrawal among U.S. high school students

PURPOSE

To examine the use of contraception at last sexual intercourse among currently sexually active adolescents.

METHODS

We analyzed data from national school-based Youth Risk Behavior Surveys (YRBS) conducted in 1991, 1993, 1995, and 1997. The YRBS is a self-administered, anonymous survey which uses a national probability sample of U.S. students in public and private schools from grades 9 through 12.

RESULTS

From 1991 to 1997, condom use significantly increased (from 46% to 57%), birth control pill use decreased (from 21% to 17%), and use of withdrawal significantly decreased (from 18% to 13%). In 1997, although more students were using condoms, 13% reported using withdrawal and 15% reported using no method to prevent pregnancy at last sexual intercourse. In 1997, condom use among females was significantly lower in the 9th grade than in the 12th grade (p <.001), whereas birth control pill use was higher (p <.001) and use of withdrawal remained stable. Among males, condom use and withdrawal use remained stable from 9th to 12th grade, whereas birth control pill use by their partner increased (p <.001).

CONCLUSIONS

Inadequate contraceptive use among sexually active adolescents continues to be a major public health problem in the United States. For young people who will not remain sexually abstinent, families, health care providers, schools, and other influential societal institutions should promote the correct and continued use of condoms as essential protection against sexually transmitted diseases and human immunodeficiency virus infection.

Contextual influences on school provision of health services

PURPOSE

To examine contextual factors that may facilitate or impede the provision of school health services.

METHODS

Using a composite database derived primarily from the National Longitudinal Study of Adolescent Health, we used logistic regression to examine how selected characteristics of communities, schools, and state-level policies are related to the provision of specific health services by high schools.

RESULTS

Schools whose students experienced more health risks were generally more likely to provide related services than schools whose students experienced fewer risks. State policies and requirements for health-related programs and services were associated with greater school-based provision of services. Availability of health care services within the community was associated with a reduced likelihood that schools provided similar services on-site; however, for some health services, the reverse was true. In general, more affluent communities were more likely to provide school health services than less affluent communities. Public schools were more likely to offer health services than private schools.

CONCLUSIONS

Certain characteristics of communities, schools, and state-level policies are associated with the provision of school health services. These contextual factors appear to operate by creating a demand for services and by creating the opportunity for schools to provide health services.

St. John's wort induces hepatic drug metabolism through activation of the pregnane X receptor

St. John's wort (Hypericum perforatum) is an herbal remedy used widely for the treatment of depression. Recent clinical studies demonstrate that hypericum extracts increase the metabolism of various drugs, including combined oral contraceptives, cyclosporin, and indinavir. In this report, we show that hyperforin, a constituent of St. John's wort with antidepressant activity, is a potent ligand (K(i) = 27 nM) for the pregnane X receptor, an orphan nuclear receptor that regulates expression of the cytochrome P450 (CYP) 3A4 monooxygenase. Treatment of primary human hepatocytes with hypericum extracts or hyperforin results in a marked induction of CYP3A4 expression. Because CYP3A4 is involved in the oxidative metabolism of >50% of all drugs, our findings provide a molecular mechanism for the interaction of St. John's wort with drugs and suggest that hypericum extracts are likely to interact with many more drugs than previously had been realized.

Orphan nuclear receptors constitutive androstane receptor and pregnane X receptor share xenobiotic and steroid ligands

Xenobiotics induce the transcription of cytochromes P450 (CYPs) 2B and 3A through the constitutive androstane receptor (CAR; NR1I3) and pregnane X receptor (PXR; NR1I2), respectively. In this report, we have systematically compared a series of xenobiotics and natural steroids for their effects on mouse and human CAR and PXR. Our results demonstrate dual regulation of PXR and CAR by a subset of compounds that affect CYP expression. Moreover, there are marked pharmacological differences between the mouse (m) and human (h) orthologs of both CAR and PXR. For example, the planar hydrocarbon 1, 4-bis[2-(3,5-dichloropyridyl-oxy)]benzene activates mCAR and hPXR but has little or no activity on hCAR and mPXR. In contrast, the CAR deactivator androstanol activates both mouse and human PXR. Similarly, the PXR activator clotrimazole is a potent deactivator of hCAR. Using radioligand binding and fluorescence resonance energy transfer assays, we demonstrate that several of the compounds that regulate mouse and human CAR, including natural steroids, bind directly to the receptors. Our results suggest that CAR, like PXR, is a steroid receptor that is capable of recognizing structurally diverse compounds. Moreover, our findings underscore the complexity in the physiologic response to xenobiotics.

Physical activity, food choice, and weight management goals and practices among US college students

INTRODUCTION

Physical activity and a healthy diet have been recommended to help reverse the increasing prevalence of overweight among adolescents and adults in the United States.

METHODS

Data is from the 1995 National College Health Risk Behavior Survey. A representative sample of US undergraduate college students (n = 4609) were analyzed to examine associations of physical activity and food choice with weight management goals and practices.

RESULTS

Based on self-reported height and weight, 35% of students were overweight or obese (body mass index > or = 25.0). Nearly half (46%) of all students reported they were trying to lose weight. Female students were less likely than male students to be overweight, but more likely to be trying to lose weight. Among female and male students, using logistic regression to control for demographics, trying to lose weight was associated with participation in vigorous physical activity and strengthening exercises, and consumption of < or = 2 servings/ day of high-fat foods. Female and male students who reported using exercise to lose weight or to keep from gaining weight were more likely than those who did not to participate in vigorous, strengthening, and moderate physical activity, and were more likely to eat > or = 5 servings/day of fruits and vegetables and < or = 2 servings/day of high-fat foods. Among students who were trying to lose weight, only 54% of females and 41% of males used both exercise and diet for weight control.

CONCLUSION

Colleges should implement programs to increase student awareness of healthy weight management methods and the importance of physical activity combined with a healthy diet.

Youth risk behavior surveillance. National Alternative High School Youth Risk Behavior Survey, United States, 1998

Alternative high schools serve approximately 280,000 students nationwide who are at high risk for failing or dropping out of regular high school or who have been expelled from regular high school because of illegal activity or behavioral problems. Such settings provide important opportunities for delivering health promotion education and services to these youth and young adults. However, before this survey, the prevalence of health-risk behaviors among students attending alternative high schools nationwide was unknown. The Youth Risk Behavior Surveillance System (YRBSS) monitors the following six categories of priority health-risk behaviors among youth and young adults: behaviors that contribute to unintentional and intentional injuries; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs) (including human immunodeficiency virus [HIV] infection); unhealthy dietary behaviors; and physical inactivity. The national Alternative High School Youth Risk Behavior Survey (ALT-YRBS) is one component of the YRBSS; it was conducted in 1998 to measure priority health-risk behaviors among students at alternative high schools. The 1998 ALT-YRBS used a three-stage cluster sample design to produce a nationally representative sample of students in grades 9-12 in the United States who attend alternative high schools. The school response rate was 81.0%, and the student response rate was 81.9%, resulting in an overall response rate of 66.3%. This report summarizes results from the 1998 ALT-YRBS. The reporting period is February-May 1998. In the United States, 73.6% of all deaths among youth and young adults aged 10-24 years results from only four causes--motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 1998 ALT-YRBS demonstrate that many students at alternative high schools engage in behaviors that increase their likelihood of death from these four causes. During the 30 days preceding the survey, 51.9% had ridden with a driver who had been drinking alcohol, 25.1% had driven a vehicle after drinking alcohol, 32.9% had carried a weapon, 64.5% had drunk alcohol, and 53.0% had used marijuana. During the 12 months preceding the survey, 15.7% had attempted suicide, and 29.0% had rarely or never worn a seat belt. Substantial morbidity among school-aged youth and young adults also results from unintended pregnancies and STDs, including HIV infection. ALT-YRBS results indicate that in 1998, a total of 87.8% of students at alternative high schools had had sexual intercourse, 54.1% of sexually active students had not used a condom at last sexual intercourse, and 5.7% had ever injected an illegal drug. Among adults aged > or = 25 years, 66.5% of all deaths result from two causes--cardiovascular disease and cancer. Most risk behaviors associated with these causes of death are initiated during adolescence. In 1998, a total of 64.1% of students at alternative high schools had smoked cigarettes during the 30 days preceding the survey, 38.3% had smoked a cigar during the 30 days preceding the survey, 71.2% had not eaten > or = 5 servings of fruits and vegetables during the day preceding the survey, and 81.0% had not attended physical education (PE) class daily. Comparing ALT-YRBS results with 1997 national YRBS results demonstrates that the prevalence of most risk behaviors is higher among students attending alternative high schools compared with students at regular high schools. Some risk behaviors are more common among certain sex and racial/ethnic subgroups of students. ALT-YRBS data can be used nationwide by health and education officials to improve policies and programs designed to reduce risk behaviors associated with the leading causes of morbidity and mortality among students attending alternative high schools.

School violence, substance use, and availability of illegal drugs on school property among US high school students

To determine if school violence is associated with substance use and availability of illegal drugs at school, this study examined data from the 1995 Youth Risk Behavior Survey, a nationally representative sample of 10,904 high school students. Adjusted odds ratios were calculated to describe the associations of tobacco, alcohol, and marijuana use (on and off school property), and availability of illegal drugs at school with five indicators of school violence--weapon-carrying, physical fighting, having property stolen or damaged, being threatened or injured, and being absent from school because of feeling unsafe. School violence indicators increased with the number of substances used and the location of use (on school property vs. off school property). School violence was associated with availability of illegal drugs at school, even among students who did not use substances. These findings suggest a need for coordinated violence and substance use prevention programs for youth in school and community settings.

Youth Risk Behavior Surveillance--National Alternative High School Youth Risk Behavior Survey, United States, 1998

PROBLEM/CONDITION

Alternative high schools serve approximately 280,000 students nationwide who are at high risk for failing or dropping out of regular high school or who have been expelled from regular high school because of illegal activity or behavioral problems. Such settings provide important opportunities for delivering health promotion education and services to these youth and young adults. However, before this survey, the prevalence of health-risk behaviors among students attending alternative high schools nationwide was unknown.

REPORTING PERIOD

February-May 1998.

DESCRIPTION OF SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors the following six categories of priority health-risk behaviors among youth and young adults: behaviors that contribute to unintentional and intentional injuries; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs) (including human immunodeficiency virus [HIV] infection); unhealthy dietary behaviors; and physical inactivity. The national Alternative High School Youth Risk Behavior Survey (ALT-YRBS) is one component of the YRBSS; it was conducted in 1998 to measure priority health-risk behaviors among students at alternative high schools. The 1998 ALT-YRBS used a three-stage cluster sample design to produce a nationally representative sample of students in grades 9-12 in the United States who attend alternative high schools. The school response rate was 81.0%, and the student response rate was 81.9%, resulting in an overall response rate of 66.3%. This report summarizes results from the 1998 ALT-YRBS.

RESULTS AND INTERPRETATION

In the United States, 73.6% of all deaths among youth and young adults aged 10-24 years results from only four causes--motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 1998 ALT-YRBS demonstrate that many students at alternative high schools engage in behaviors that increase their likelihood of death from these four causes. During the 30 days preceding the survey, 51.9% had ridden with a driver who had been drinking alcohol, 25.1% had driven a vehicle after drinking alcohol, 32.9% had carried a weapon, 64.5% had drunk alcohol, and 53.0% had used marijuana. During the 12 months preceding the survey, 15.7% had attempted suicide, and 29.0% had rarely or never worn a seat belt. Substantial morbidity among school-aged youth and young adults also results from unintended pregnancies and STDs, including HIV infection. ALT-YRBS results indicate that in 1998, a total of 87.8% of students at alternative high schools had had sexual intercourse, 54.1% of sexually active students had not used a condom at last sexual intercourse, and 5.7% had ever injected an illegal drug. Among adults aged > or =25 years, 66.5% of all deaths result from two causes--cardiovascular disease and cancer. Most risk behaviors associated with these causes of death are initiated during adolescence. In 1998, a total of 64.1% of students at alternative high schools had smoked cigarettes during the 30 days preceding the survey, 38.3% had smoked a cigar during the 30 days preceding the survey, 71.2% had not eaten > or =5 servings of fruits and vegetables during the day preceding the survey, and 81.0% had not attended physical education (PE) class daily. Comparing ALT-YRBS results with 1997 national YRBS results demonstrates that the prevalence of most risk behaviors is higher among students attending alternative high schools compared with students at regular high schools. Some risk behaviors are more common among certain sex and racial/ethnic subgroups of students.

PUBLIC HEALTH ACTION

ALT-YRBS data can be used nationwide by health and education officials to improve policies and programs designed to reduce risk behaviors associated with the leading causes of morbidity and mortality among students attending alternative high schools.

A peroxisome proliferator-activated receptor gamma ligand inhibits adipocyte differentiation

The peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that regulate glucose and lipid homeostasis. The PPARgamma subtype plays a central role in the regulation of adipogenesis and is the molecular target for the 2, 4-thiazolidinedione class of antidiabetic drugs. Structural studies have revealed that agonist ligands activate the PPARs through direct interactions with the C-terminal region of the ligand-binding domain, which includes the activation function 2 helix. GW0072 was identified as a high-affinity PPARgamma ligand that was a weak partial agonist of PPARgamma transactivation. X-ray crystallography revealed that GW0072 occupied the ligand-binding pocket by using different epitopes than the known PPAR agonists and did not interact with the activation function 2 helix. In cell culture, GW0072 was a potent antagonist of adipocyte differentiation. These results establish an approach to the design of PPAR ligands with modified biological activities.

Estimates of mouse oviductal fluid tonicity based on osmotic responses of embryos

Zygotes and early cleavage-stage embryos are very sensitive to increased osmolality in vitro, although the tonicity of their in vivo environment, oviductal fluid, is unknown. A preference for low osmolality in vitro might imply similar conditions in vivo or be specific to culture. Previous electron probe x-ray microanalysis measurements of total ion content predicted oviductal fluid osmolalities of 310-360 mOs/kg, higher than osmolalities tolerated by mouse zygotes in vitro. However, such indirect estimates may not reflect the tonicity experienced by embryos. We have now used embryos themselves as osmosensors to determine the tonicity of mouse oviductal fluid. In one method, we measured the mean volume of zygotes in undiluted oviductal fluid and compared this to the mean volumes measured for zygotes in media spanning a range of osmolalities. The osmolality corresponding to the measured mean volume in oviductal fluid was taken to be isotonic. In another, independent method, the sizes of zygotes and two-cell embryos were measured as a function of time beginning immediately after removal from oviducts. The osmolality in which the embryos neither swelled nor shrank was taken to be isotonic. Both methods yielded approximately the same range for the tonicity of oviductal fluid: around 290-300 mOs/kg.

N-(2-Benzoylphenyl)-L-tyrosine PPARgamma agonists. 2. Structure-activity relationship and optimization of the phenyl alkyl ether moiety

We previously reported the identification of (2S)-((2-benzoylphenyl)amino)-3-¿4-[2-(5-methyl-2-phenyloxazol-4-y l)e thoxy]phenyl¿propanoic acid (2) (PPARgamma pKi = 8.94, PPARgamma pEC50 = 9.47) as a potent and selective PPARgamma agonist. We now report the expanded structure-activity relationship around the phenyl alkyl ether moiety by pursuing both a classical medicinal chemistry approach and a solid-phase chemistry approach for analogue synthesis. The solution-phase strategy focused on evaluating the effects of oxazole and phenyl ring replacements of the 2-(5-methyl-2-phenyloxazol-4-yl)ethyl side chain of 2 with several replacements providing potent and selective PPARgamma agonists with improved aqueous solubility. Specifically, replacement of the phenyl ring of the phenyloxazole moiety with a 4-pyridyl group to give 2(S)-((2-benzoylphenyl)amino)-3-¿4-[2-(5-methyl-2-pyridin-4-yloxazol+ ++- 4-yl)ethoxy]phenyl¿propionic acid (16) (PPARgamma pKi = 8.85, PPARgamma pEC50 = 8.74) or a 4-methylpiperazine to give 2(S)-((2-benzoylphenyl)amino)-3-(4-¿2-[5-methyl-2-(4-methylpiperazin+ ++- 1-yl)thiazol-4-yl]ethoxy¿phenyl)propionic acid (24) (PPARgamma pKi = 8.66, PPARgamma pEC50 = 8.89) provided two potent and selective PPARgamma agonists with increased solubility in pH 7.4 phosphate buffer and simulated gastric fluid as compared to 2. The second strategy took advantage of the speed and ease of parallel solid-phase analogue synthesis to generate a more diverse set of phenyl alkyl ethers which led to the identification of a number of novel, high-affinity PPARgamma ligands (PPARgamma pKi's 6.98-8.03). The combined structure-activity data derived from the two strategies provide valuable insight on the requirements for PPARgamma binding, functional activity, selectivity, and aqueous solubility.

N-(2-Benzoylphenyl)-L-tyrosine PPARgamma agonists. 1. Discovery of a novel series of potent antihyperglycemic and antihyperlipidemic agents

We have identified a novel series of antidiabetic N-(2-benzoylphenyl)-L-tyrosine derivatives which are potent, selective PPARgamma agonists. Through the use of in vitro PPARgamma binding and functional assays (2S)-3-(4-(benzyloxy)phenyl)-2-((1-methyl-3-oxo-3-phenylpropenyl)+ ++amin o)propionic acid (2) was identified as a structurally novel PPARgamma agonist. Structure-activity relationships identified the 2-aminobenzophenone moiety as a suitable isostere for the chemically labile enaminone moiety in compound 2, affording 2-((2-benzoylphenyl)amino)-3-(4-(benzyloxy)phenyl)propionic acid (9). Replacement of the benzyl group in 9 with substituents known to confer in vivo potency in the thiazolidinedione (TZD) class of antidiabetic agents provided a dramatic increase in the in vitro functional potency and affinity at PPARgamma, affording a series of potent and selective PPARgamma agonists exemplified by (2S)-((2-benzoylphenyl)amino)-3-¿4-[2-(methylpyridin-2-ylamino+ ++)ethoxy ]phenyl¿propionic acid (18), 3-¿4-[2-(benzoxazol-2-ylmethylamino)ethoxy]phenyl¿-(2S)-((2- benzoylph enyl)amino)propanoic acid (19), and (2S)-((2-benzoylphenyl)amino)-3-¿4-[2-(5-methyl-2-phenyloxazol-4-y l)e thoxy]phenyl¿propanoic acid (20). Compounds 18 and 20 show potent antihyperglycemic and antihyperlipidemic activity when given orally in two rodent models of type 2 diabetes. In addition, these analogues are readily prepared in chiral nonracemic fashion from L-tyrosine and do not show a propensity to undergo racemization in vitro. The increased potency of these PPARgamma agonists relative to troglitazone may translate into superior clinical efficacy for the treatment of type 2 diabetes.

N-(2-Benzoylphenyl)-L-tyrosine PPARgamma agonists. 3. Structure-activity relationship and optimization of the N-aryl substituent

3-¿4-[2-(Benzoxazol-2-ylmethylamino)ethoxy]phenyl¿-(2S)-((2- benzoylph enyl)amino)propionic acid (1) and (2S)-((2-benzoylphenyl)amino)-3-¿4-[2-(5-methyl-2-phenyloxazol-4-y l)e thoxy]phenyl¿propionic acid (2) are peroxisome proliferator-activated receptor gamma (PPARgamma) agonists and have antidiabetic activity in rodent models of type 2 diabetes. As part of an effort to develop the SAR of the N-2-benzoylphenyl moiety of 1 and 2, a series of novel carboxylic acid analogues, 23-66, modified only in the N-2-benzoylphenyl moiety were synthesized from L-tyrosine and evaluated as PPARgamma agonists. In general, only modest changes in the N-2-benzoylphenyl moiety of 1 and 2 are tolerated. More specifically, the best changes involve bioisosteric replacement of one of the two phenyl rings of this moiety. Addition of substituents to this moiety generally produced compounds that are less active in the cell-based functional assays of PPARgamma activity although binding affinity to PPARgamma may be maintained. A particularly promising set of analogues is the anthranilic acid esters 63-66 in which the phenyl ring in the 2-benzoyl group of 1 and 2 has been replaced by an alkoxy group. In particular, (S)-2-(1-carboxy-2-¿4-[2-(5-methyl-2-phenyloxazol-4-yl)ethoxy]phen yl¿ ethylamino)benzoic acid methyl ester (63) has a pKi of 8.43 in the binding assay using human PPARgamma ligand binding domain and a pEC50 of 9.21 in the in vitro murine lipogenesis functional assay of PPARgamma activity. Finally, 63 was found to normalize glycemia when dosed at 3 mg/kg bid po in the Zucker diabetic fatty rat model of type 2 diabetes.

Heterotopic neurogenesis in a rat with cortical heterotopia

Early cellular development was studied in the neocortex of the tish rat. This neurological mutant is seizure-prone and displays cortical heterotopia similar to those observed in certain epileptic patients. The present study demonstrates that a single cortical preplate is formed in a typical superficial position of the developing tish neocortex. In contrast, two cortical plates are formed: one in a normotopic position and a second in a heterotopic position in the intermediate zone. As the normotopic cortical plate is formed, it characteristically separates the subplate cells from the superficial Cajal-Retzius cells. In contrast, the heterotopic cortical plate is not intercalated between the preplate cells because of its deeper position in the developing cortex. Cellular proliferation occurs in two zones of the developing tish cortex. One proliferative zone is located in a typical position in the ventricular/subventricular zone. A second proliferative zone is located in a heterotopic position in the superficial intermediate zone, i.e., between the two cortical plates. This misplaced proliferative zone may contribute cells to both the normotopic and heterotopic cortical plates. Taken together, these findings indicate that misplaced cortical plate cells, but not preplate cells, comprise the heterotopia of the tish cortex. Heterotopic neurogenesis is an early developmental event that is initiated before the migration of most cortical plate cells. It is concluded that misplaced cellular proliferation, in addition to disturbed neuronal migration, can play a key role in the formation of large cortical heterotopia.

Comparison of TNFalpha and TNFbeta cytolytic mechanisms in human ovarian and cervical carcinoma cell lines

OBJECTIVES

The aim of this study was to determine the potential and mechanism of tumor necrosis factor beta (TNFbeta) mediated cytolysis in human ovarian and cervical carcinoma cells.

METHODS

The cytolytic potential of tumor necrosis factor alpha (TNFalpha) and TNFbeta was determined using the TNF reference cell line L929 and human ovarian (SK-OV-3, CaOV-3) and cervical (SiHa, HT-3) carcinoma cell lines. We have previously reported the effects of the lipoxygenase enzyme inhibitor, nordihydroguaiaretic acid, the oxygen radical scavenger glutathione, and fragmented DNA-specific staining with diamidino-2-phenylindole and ApopTag on TNFalpha-mediated cytolysis in these cells. The effects of these agents on TNFbeta-mediated cytolysis were determined.

RESULTS

All of the cell lines express a protein-synthesis-dependent TNFalpha and TNFbeta resistance mechanisms. When protein synthesis is inhibited the cytolytic activity of TNFbeta was fivefold greater than that of TNFalpha in L929 cells. In contrast, the cytolytic activity of TNFalpha was fivefold greater than that of TNFbeta in the human cells. Like the TNFalpha cytolytic mechanism, the TNFbeta cytolytic mechanism is dependent on lipoxygenase enzymes, but not oxygen radicals, and results in apoptosis.

CONCLUSIONS

To date there is little information about the cytolytic potential of TNFbeta in human cells. The fact that the cytolytic mechanism of TNFbeta appears very similar to that of TNFalpha could be important to our understanding of the potential of these closely related cytokines in anticancer therapies. Although the cytolytic potential of TNFbeta is greater than that of TNFalpha in mouse cells, this is not true in human cells and could limit the efficacy of TNFbeta in anticancer therapies.

Youth Risk Behavior Surveillance--United States, 1997. State and Local YRBSS Coordinators

Priority health-risk behaviors, which contribute to the leading causes of mortality and morbidity among youth and adults, often are established during youth, extend into adulthood, and are interrelated. The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults--behaviors that contribute to unintentional and intentional injuries; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs) (including human immunodeficiency virus [HIV] infection); unhealthy dietary behaviors; and physical inactivity. The YRBSS includes a national school-based survey conducted by the Centers for Disease Control and Prevention as well as state, territorial, and local school-based surveys conducted by education and health agencies. This report summarizes results from the national survey, 33 state surveys, 3 territorial surveys, and 17 local surveys conducted among high school students from February through May 1997. In the United States, 73% of all deaths among youth and young adults 10-24 years of age result from only four causes: motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the national 1997 YRBSS demonstrate that many high school students engage in behaviors that increase their likelihood of death from these four causes--19.3% had rarely or never worn a seat belt; during the 30 days preceding the survey, 36.6% had ridden with a driver who had been drinking alcohol; 18.3% had carried a weapon during the 30 days preceding the survey; 50.8% had drunk alcohol during the 30 days preceding the survey; 26.2% had used marijuana during the 30 days preceding the survey; and 7.7% had attempted suicide during the 12 months preceding the survey. Substantial morbidity among school-age youth, young adults, and their children also result from unintended pregnancies and STDs, including HIV infection. YRBSS results indicate that in 1997, 48.4% of high school students had ever had sexual intercourse; 43.2% of sexually active students had not used a condom at last sexual intercourse; and 2.1% had ever injected an illegal drug. Of all deaths and substantial morbidity among adults greater than or equal to 25 years of age, 67% result from two causes--cardiovascular disease and cancer. Most of the risk behaviors associated with these causes of death are initiated during adolescence. In 1997, 36.4% of high school students had smoked cigarettes during the 30 days preceding the survey; 70.7% had not eaten five or more servings of fruits and vegetables during the day preceding the survey; and 72.6% had not attended physical education class daily. These YRBSS data are already being used by health and education officials to improve national, state, and local policies and programs to reduce risks associated with the leading causes of morbidity and mortality. YRBSS data also are being used to measure progress toward achieving 21 national health objectives and one of the eight National Education Goals.

Anticancer activity of glaucarubinone analogues

A series of glaucarubinone analogues, obtained from natural sources as well as synthesized by us, were studied both in vitro and in vivo. The focus of the in vitro assessment was to define solid tumor-selective compounds by quantitating differential cytotoxic activity between murine and human solid tumor cells and either murine leukemia or normal cells. Subsequent in vivo studies were aimed at determining the therapeutic efficacy of these analogues against the murine models. Structure-activity analysis consequent to both the in vitro and in vivo studies demonstrated that few changes could be made in the parent glaucarubinone structure (outside of the C-15 position) without abrogating either cytotoxicity or potency. However, significant changes could be made at the C-15 position which modified, either enhanced or diminished, in vitro differential cytotoxicity, potency, human solid tumor selectively, and differential cytotoxicity to a MDR-expressing murine mammary tumor.

Characteristics of health education among secondary schools--School Health Education Profiles, 1996

PROBLEM/CONDITION

School health education (e.g., classroom training) is an essential component of school health programs; such education promotes the health of youth and improves overall public health.

REPORTING PERIOD

February-May 1996.

DESCRIPTION OF SYSTEM

The School Health Education Profiles monitor characteristics of health education in middle or junior high schools and senior high schools. The Profiles are school-based surveys conducted by state and local education agencies. This report summarizes results from 35 state surveys and 13 local surveys conducted among representative samples of school principals and lead health education teachers. The lead health education teacher is the person who coordinates health education policies and programs within a middle or junior high school and senior high school.

RESULTS

During the study period, almost all schools in states and cities required health education in grades 6-12; of these, a median of 87.6% of states and 75.8% of cities taught a separate health education course. The median percentage of schools that tried to increase student knowledge on certain topics (i.e., prevention of tobacco use, alcohol and other drug use, pregnancy, human immunodeficiency virus [HIV] infection, other sexually transmitted diseases, violence, or suicide; dietary behaviors and nutrition; and physical activity and fitness) was > 72% for each of these topics. The median percentage of schools that tried to improve certain student skills (i.e., communication, decision making, goal setting, resisting social pressures, nonviolent conflict resolution, stress management, and analysis of media messages) was > 69% for each of these skills. The median percentage of schools that had a health education teacher coordinate health education was 33.0% across states and 26.8% across cities. Almost all schools taught HIV education as part of a required health education course (state median: 94.3%; local median: 98.1%), and more than half (state median: 69.5%; local median: 82.5%) had a written policy on HIV infection among students and school staff. A median of 41.0% of schools across states and a median of 25.8% of schools across cities had a lead health education teacher with professional preparation in health and physical education, and < 25% of schools across states or cities had a lead health education teacher with professional preparation in health education only. Across states, the median percentage of schools, whose lead health education teacher had received in-service training on certain health education topics, ranged from 15.6% for suicide prevention to 51.4% for HIV prevention; across cities, the median percentage ranged from 26.2% for suicide prevention to 76.1% for HIV prevention. A median of 19.7% of schools across states and 18.1% of schools across cities had a school health advisory council. Of the schools that received parental feedback (state median: 59.1%; local median: 54.2%), > 78% reported receiving positive feedback.

INTERPRETATION

More than 75% of schools have a required course in health education to help provide students with the knowledge and skills they need to adopt healthy lifestyles.

ACTIONS TAKEN

The School Health Education Profiles data are being used by state and local education officials to improve school health education and HIV education.

Youth risk behavior surveillance--United States, 1997

PROBLEM/CONDITION

Priority health-risk behaviors, which contribute to the leading causes of mortality and morbidity among youth and adults, often are established during youth, extend into adulthood, and are interrelated.

REPORTING PERIOD

February-May 1997.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults--behaviors that contribute to unintentional and intentional injuries; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs) (including human immunodeficiency virus [HIV] infection); unhealthy dietary behaviors; and physical inactivity. The YRBSS includes a national school-based survey conducted by CDC as well as state, territorial, and local school-based surveys conducted by education and health agencies. This report summarizes results from the national survey, 33 state surveys, 3 territorial surveys, and 17 local surveys conducted among high school students from February through May 1997.

RESULTS AND INTERPRETATION

In the United States, 73% of all deaths among youth and young adults 10-24 years of age result from only four causes: motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the national 1997 YRBSS demonstrate that many high school students engage in behaviors that increase their likelihood of death from these four causes--19.3% had rarely or never worn a seat belt; during the 30 days preceding the survey, 36.6% had ridden with a driver who had been drinking alcohol; 18.3% had carried a weapon during the 30 days preceding the survey; 50.8% had drunk alcohol during the 30 days preceding the survey; 26.2% had used marijuana during the 30 days preceding the survey; and 7.7% had attempted suicide during the 12 months preceding the survey. Substantial morbidity among school-age youth, young adults, and their children also result from unintended pregnancies and STDs, including HIV infection. YRBSS results indicate that in 1997, 48.4% of high school students had ever had sexual intercourse; 43.2% of sexually active students had not used a condom at last sexual intercourse; and 2.1% had ever injected an illegal drug. Of all deaths and substantial morbidity among adults > or = 25 years of age, 67% result from two causes--cardiovascular disease and cancer. Most of the risk behaviors associated with these causes of death are initiated during adolescence. In 1997, 36.4% of high school students had smoked cigarettes during the 30 days preceding the survey; 70.7% had not eaten five or more servings of fruits and vegetables during the day preceding the survey; and 72.6% had not attended physical education class daily.

ACTIONS TAKEN

These YRBSS data are already being used by health and education officials to improve national, state, and local policies and programs to reduce risks associated with the leading causes of morbidity and mortality. YRBSS data also are being used to measure progress toward achieving 21 national health objectives and 1 of the 8 National Education Goals.

Osmolarity-dependent glycine accumulation indicates a role for glycine as an organic osmolyte in early preimplantation mouse embryos

Mouse zygotes and early cleavage-stage embryos are sensitive to increased osmolarity. However, development can occur at higher osmolarities if any of a number of organic compounds are present. One of the most effective of these is glycine. We have found that the amount of glycine accumulated by embryos during in vitro culture from the zygote to two-cell stage depends on the osmolarity of the medium, with significantly more glycine accumulated at 310 or 340 mOsM than at 250 mOsM. The accumulated glycine is largely retained in a freely diffusible form, as it can be released via a swelling-activated pathway in two-cell embryos. Increased glycine accumulation does not seem to depend on an increase in its rate of transport. The transport rate is not higher in two-cell embryos that have been cultured from zygotes in hypertonic vs. normal medium, and hypertonicity only slightly stimulates transport in zygotes. Our results indicate that glycine functions as an organic osmolyte in early mouse embryos.

N-Phenylamidines as selective inhibitors of human neuronal nitric oxide synthase: structure-activity studies and demonstration of in vivo activity

Selective inhibition of the neuronal isoform of nitric oxide synthase (NOS) compared to the endothelial and inducible isoforms may be required for treatment of neurological disorders caused by excessive production of nitric oxide. Recently, we described N-(3-(aminomethyl)benzyl)acetamidine (13) as a slow, tight-binding inhibitor, highly selective for human inducible nitric oxide synthase (iNOS). Removal of a single methylene bridge between the amidine nitrogen and phenyl ring to give N-(3-(aminomethyl)phenyl)acetamidine (14) dramatically altered the selectivity to give a neuronal selective nitric oxide synthase (nNOS) inhibitor. Part of this large shift in selectivity was due to 14 being a rapidly reversible inhibitor of iNOS in contrast to the essentially irreversible inhibition of iNOS observed with 13. Structure-activity studies revealed that a basic amine functionality tethered to an aromatic ring and a sterically compact amidine are key pharmacophores for this class of NOS inhibitors. Maximal nNOS inhibition potency was achieved with N-(3-(aminomethyl)phenyl)-2-furanylamidine (77) (Ki-nNOS = 0.006 microM; Ki-eNOS = 0.35 microM; Ki-iNOS = 0.16 microM). Finally, alpha-fluoro-N-(3-(aminomethyl)phenyl)acetamidine (74) (Ki-nNOS = 0. 011 microM; Ki-eNOS = 1.1 microM; Ki-iNOS = 0.48 microM) had excellent brain penetration and inhibited nNOS in a rat brain slice assay as well as in the rat brain (cerebellum) in vivo. Thus, N-phenylamidines should be useful in validating the role of nNOS in neurological disorders.

Sexual behavior among U.S. high school students, 1990-1995

CONTEXT

High rates of unintended pregnancy and sexually transmitted diseases (STDs), including HIV infection, among adolescents are major public health concerns that have created interest in trends in teenage sexual activity.

METHODS

Nationally representative data from Youth Risk Behavior Surveys conducted in 1990, 1991, 1993 and 1995 are used to examine levels of sexual experience, age at first intercourse, current sexual activity and condom use at last intercourse among students in grades 9-12.

RESULTS

The proportion of students who reported being sexually experienced remained at 53-54% from 1990 through 1995, while the percentage of sexually active students who used condoms at last intercourse rose from 46% to 54% between 1991 and 1995. Black students were more likely than white students to report being sexually experienced, being currently sexually active and having had four or more lifetime sexual partners; black students also reported a significantly younger age at first intercourse. Gender differences in sexual behavior were found more frequently among black students than among white or Hispanic students.

CONCLUSIONS

Although levels of sexual experience for high school students in the United States have not risen during the 1990s, a very high percentage of students continue to be at risk for unintended pregnancy and STDs, including HIV infection.

Synthesis, SAR and pharmacology of CP-293,019: a potent, selective dopamine D4 receptor antagonist

A series of novel, potent and selective pyrido[1,2-a]pyrazine dopamine D4 receptor antagonists are reported including CP-293,019 (D4 Ki = 3.4 nM, D2 Ki > 3,310 nM), which also inhibits apomorphine-induced hyperlocomotion in rats after oral dosing.

Co-occurrence of health-risk behaviors among adolescents in the United States

PURPOSE

Although it is common for adolescents to experiment with several health-risk behaviors before reaching adulthood, little is known about the co-occurrence of these behaviors. The purposes of this study were to determine the co-occurrence of specific health-risk behaviors among a nationally representative sample of adolescents, and to examine whether the distribution of multiple risk behaviors varies by age, sex, and school enrollment status.

METHODS

This study analyzed survey data from a United States national probability sample (n = 10,645) of youth aged 12-21 years. Survey items measuring current seat belt use, weapon carrying, tobacco, alcohol, and other drug use, and sexual behavior were included in the analysis.

RESULTS

The majority of adolescents aged 12-17 years did not engage in multiple health-risk behaviors. However, the prevalence of multiple risk behaviors increased dramatically with age. While only 1 in 12 adolescents aged 12-13 years engaged in two or more of these behaviors, one-third of those aged 14-17 years and half of the college-aged youth (18-21 years) did so. Male respondents and out-of-school youth aged 14-17 years were more likely to engage in multiple health-risk behaviors than were other respondents.

CONCLUSIONS

These results suggest that the likelihood that adolescents engage in multiple health-risk behaviors is related to age and that many adolescents engage in these behaviors serially rather than at the same time.

Weapon-carrying, physical fighting, and fight-related injury among U.S. adolescents

INTRODUCTION

Access to firearms and other weapons has been cited as an important factor contributing to the rise in violence-related injury among adolescents in the United States.

METHODS

Data from the Youth Risk Behavior Survey supplement to the 1992 National Health Interview Survey were analyzed to examine relationships among weapon-carrying, physical fighting, and fight-related injury among U.S. adolescents aged 12-21 years (N = 10,269). Adjusted odds ratios (OR) were used to describe the association of weapon-carrying during the past 30 days with physical fighting and fight-related injury during the past 12 months.

RESULTS

Weapon-carrying (15%) and physical fighting (39%) were common among adolescents. One out of 30 (3.3%) adolescents reported receiving medical care for fight-related injuries. Controlling for demographic characteristics, youth who carried weapons were more likely than those who did not to have been in a physical fight (OR = 3.3). The association between weapon-carrying and physical fighting was stronger among females (OR = 5.0) than among males (OR = 2.9), but did not vary significantly by age, race/ethnicity, or place of residence (urban, suburban, rural). Controlling for frequency of physical fighting and demographics, adolescents who carried a handgun (OR = 2.6) or other weapon (OR = 1.6) were more likely than those who did not carry a weapon to have had medical care for fight-related injuries.

CONCLUSIONS

Among adolescents, weapon-carrying is associated with increased involvement in physical fighting and a greater likelihood of injury among those who do fight. Efforts to reduce fight-related injuries among youth should stress avoidance of weapon-carrying.

Age of initiating selected health-risk behaviors among high school students in the United States

PURPOSE

To estimate and compare the age of initiation of alcohol use, cigarette smoking, sexual intercourse, and marijuana use among female and male students in U.S. high schools.

METHODS

Using data from the 1991 and 1993 national school-based Youth Risk Behavior Surveys, life-table analysis was used to create hypothetical cohorts to estimate age of initiation of selected health-risk behaviors. The sample size was 12,272 in 1991 and 16,296 in 1993, with an overall response rate of 68% in 1991 and 70% in 1993.

RESULTS

Male students initiate each of these behaviors earlier than female students, but the pace of initiation for females accelerates so that by age 15 years the cumulative proportion of male and female students who have initiated these behaviors is similar. For both female and male students, the youngest cohort appears to initiate use of alcohol and sexual intercourse at earlier ages than older cohorts. Similarly, the younger cohorts of female students appear to initiate smoking cigarettes and using marijuana at earlier ages than older cohorts.

CONCLUSIONS

Many high school students are initiating alcohol use, cigarette smoking, sexual intercourse, and marijuana use at early ages. These data suggest a need for intensive intervention programs by middle/junior high school to motivate and prepare students to avoid these behaviors. Clinicians should begin screening and counseling for risk behaviors in early adolescence.

Results from the 1995 National College Health Risk Behavior Survey

Results from the 1995 National College Health Risk Behavior Survey, which monitored health risk behaviors among US college and university undergraduates, suggest that many students' behaviors increase their likelihood of adverse health outcomes. During the 30 days preceding the survey, 34% of the participants had consumed five or more alcoholic drinks on at least one occasion, and 27% had drunk alcohol and driven a car. Thirty-one percent had smoked cigarettes regularly during their lifetimes, 49% had ever used marijuana, 30% had used a condom during their last sexual intercourse, 21% were overweight, and 38% had participated in vigorous physical activity on 3 or more of the 7 days preceding the survey. These data were analyzed by gender, age group, race and ethnicity, and institution type. They can be used by those responsible for the health and education of college students to reduce risks associated with the leading causes of mortality and morbidity.

A genetic animal model of human neocortical heterotopia associated with seizures

Malformations of the human neocortex are commonly associated with developmental delays, mental retardation, and epilepsy. This study describes a novel neurologically mutant rat exhibiting a forebrain anomaly resembling the human neuronal migration disorder of double cortex. This mutant displays a telencephalic internal structural heterotopia (tish) that is inherited in an autosomal recessive manner. The bilateral heterotopia is prominent below the frontal and parietal neocortices but is rarely observed in temporal neocortex. Neurons in the heterotopia exhibit neocortical-like morphologies and send typical projections to subcortical sites; however, characteristic lamination and radial orientation are disturbed in the heterotopia. The period of neurogenesis during which cells in the heterotopia are generated is the same as in the normotopic neocortex; however, the cells in the heterotopia exhibit a "rim-to-core" neurogenetic pattern rather than the characteristic "inside-out" pattern observed in normotopic neocortex. Similar to the human syndrome of double cortex, some of the animals with the tish phenotype exhibit spontaneous recurrent electrographic and behavioral seizures. The tish rat is a unique neurological mutant that shares several features with a human cortical malformation associated with epilepsy. On the basis of its regional connectivity, histological composition, and period of neurogenesis, the heterotopic region in the tish rat is neocortical in nature. This neurological mutant represents a novel model system for investigating mechanisms of aberrant neocortical development and is likely to provide insights into the cellular and molecular events contributing to seizure development in dysplastic neocortex.

Youth risk behavior surveillance--United States, 1995

Priority health-risk behaviors that contribute to the leading causes of mortality, morbidity, and social problems among youth and adults often are established during youth, extend into adulthood, and are interrelated. The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults: behaviors that contribute to unintentional and intentional injuries, tobacco use, alcohol and other drug use, sexual behaviors, unhealthy dietary behaviors, and physical inactivity. The YRBSS includes both a national school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education agencies. This report summarizes results from the national survey, 35 state surveys, and 16 local surveys conducted among high school students from February through May 1995. In the United States, 72% of all deaths among school-age youth and young adults result from four causes: motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 1995 YRBSS suggest that many high school students practice behaviors that may increase their likelihood of death from these four causes: 21.7% had rarely or never used a safety belt, 38.8% had ridden with a driver who had been drinking alcohol during the 30 days preceding the survey, 20.0% had carried a weapon during the 30 days preceding the survey, 51.6% had drunk alcohol during the 30 days preceding the survey, 25.3% had used marijuana during the 30 days preceding the survey, and 8.7% had attempted suicide during the 12 months preceding the survey. Substantial morbidity and social problems among school-age youth and young adults also result from unintended pregnancies and sexually transmitted diseases, including HIV infection. YRBSS results indicate that in 1995, 53.1% of high school students had experienced sexual intercourse, 45.6% of sexually active students had not used a condom at last sexual intercourse, and 2.0% had ever injected an illegal drug. Among adults, 65% of all deaths result from three causes: heart disease, cancer, and stroke. Most of the risk behaviors associated with these causes of death are initiated during adolescence. In 1995, 34.8% of high school students had smoked cigarettes during the 30 days preceding the survey, 39.5% had eaten more than two servings of foods typically high in fat content during the day preceding the survey, and only 25.4% had attended physical education class daily. YRBSS data are being used nationwide by health and education officials to improve national, state, and local policies and programs designed to reduce risks associated with the leading causes of mortality and morbidity. YRBSS data also are being used to measure progress toward achieving 21 national health objectives and one of eight National Education Goals.

Youth Risk Behavior Surveillance--United States, 1995

PROBLEM/CONDITION

Priority health-risk behaviors that contribute to the leading causes of mortality, morbidity, and social problems among youth and adults often are established during youth, extend into adulthood, and are interrelated.

REPORTING PERIOD

February through May 1995.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults: behaviors that contribute to unintentional and intentional injuries, tobacco use, alcohol and other drug use, sexual behaviors, unhealthy dietary behaviors, and physical inactivity. The YRBSS includes both a national school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education agencies. This report summarizes results from the national survey, 35 state surveys, and 16 local surveys conducted among high school students from February through May 1995.

RESULTS AND INTERPRETATION

In the United States, 72% of all deaths among school-age youth and young adults result from four causes: motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 1995 YRBSS suggest that many high school students practice behaviors that may increase their likelihood of death from these four causes: 21.7% had rarely or never used a safety belt, 38.8% had ridden with a driver who had been drinking alcohol during the 30 days preceding the survey, 20.0% had carried a weapon during the 30 days preceding the survey, 51.6% had drunk alcohol during the 30 days preceding the survey, 25.3% had used marijuana during the 30 days preceding the survey, and 8.7% had attempted suicide during the 12 months preceding the survey. Substantial morbidity and social problems among school-age youth and young adults also result from unintended pregnancies and sexually transmitted diseases, including human immunodeficiency virus infection. YRBSS results indicate that in 1995, 53.1% of high school students had had sexual intercourse, 45.6% of sexually active students had not used a condom at last sexual intercourse, and 2.0% had ever injected an illegal drug. Among adults, 65% of all deaths result from three causes: heart disease, cancer and stroke. Most of the risk behaviors associated with these causes of death are initiated during adolescence. In 1995, 34.8% of high school students had smoked cigarettes during the 30 days preceding the survey, 39.5% had eaten more than two servings of foods typically high in fat content during the day preceding the survey, and only 25.4% had attended physical education class daily.

ACTIONS TAKEN

YRBSS data are being used nationwide by health and education officials to improve national, state, and local policies and programs designed to reduce risks associated with the leading causes of mortality and morbidity. YRBSS data also are being used to measure progress toward achieving 21 national health objectives and one of eight National Education Goals.

The effect of socioeconomic status on chronic disease risk behaviors among US adolescents

OBJECTIVE

To examine the relationship between socioeconomic status and risk behaviors for chronic disease among a nationally representative sample of adolescents in the United States.

DESIGN

Household survey, the Youth Risk Behavior Survey supplement to the 1992 National Health Interview Survey.

SETTING

United States.

PARTICIPANTS

Nationally representative sample of 6321 adolescents aged 12 to 17 years.

MAIN OUTCOME MEASURES

Standardized prevalence rates and logistic and multiple regression models were used to examine the effect of educational level of the responsible adult and family income on 5 risk behaviors for chronic disease among adolescents--cigarette smoking, sedentary lifestyle, insufficient consumption of fruits and vegetables, excessive consumption of foods high in fat, and episodic heavy drinking of alcohol.

RESULTS

Most adolescents (63%) reported 2 or more of the 5 risk behaviors. Controlling for age, sex, race/ethnicity, and school enrollment status of adolescents, as the educational level of the responsible adult increased, cigarette smoking, sedentary lifestyle, and insufficient consumption of fruits and vegetables were less likely among adolescents. Among girls, but not boys, consumption of foods high in fat decreased as education of the responsible adult increased. As family income increased, adolescents were less likely to smoke cigarettes, less likely to be sedentary, and less likely to engage in episodic heavy drinking.

CONCLUSION

Among adolescents, risk behaviors for chronic disease are common and inversely related to socioeconomic status. Improved community- and school-based programs to prevent such behaviors among adolescents are needed, especially among socially and economically disadvantaged youth.

Characterization of the protein synthesis independent TNFalpha lytic mechanism in human ovarian and cervical carcinoma cell lines

The analysis of the lytic mechanism initiated by TNFalpha in three human ovarian cell lines (CAOV-3, SK-OV-3, and OVCAR-3) and in three human cervical cell lines (SIHa, HT-3, and ME-180) in the presence of inhibitors of protein synthesis indicates that this lytic mechanism is similar to the protein synthesis-independent lytic mechanism initiated by TNFalpha in L929 cells. In addition to being independent of protein synthesis, the lytic mechanism initiated by TNFalpha in human ovarian and cervical carcinoma cells is also not dependent on the formation of oxygen radicals, as shown by the inability of the oxygen radical scavengers DMSO or glutathione to inhibit lysis. In spite of the fact that oxygen radicals are not involved in lysis, the TNFalpha lytic mechanism initiated in the human ovarian and cervical carcinoma cells is dependent on the activity of lipoxygenase enzymes. This was shown by the ability of the lipoxygenase enzyme inhibitor, NDGA, to block TNFalpha-mediated lysis. Using DNA-specific staining (DAPI and Apoptag) it was shown that when the human ovarian and cervical carcinoma cells are lysed by TNFalpha, death occurs via apoptosis.

An alpha-mercaptoacrylic acid derivative is a selective nonpeptide cell-permeable calpain inhibitor and is neuroprotective

Overactivation of calcium-activated neutral protease (calpain) has been implicated in the pathophysiology of several degenerative conditions, including stroke, myocardial ischemia, neuromuscular degeneration, and cataract formation. Alpha-mercaptoacrylate derivatives (exemplified by PD150606), with potent and selective inhibitory actions against calpain, have been identified. PD150606 exhibits the following characteristics: (i) Ki values for mu- and m-calpains of 0.21 microM and 0.37 microM, respectively, (ii) high specificity for calpains relative to other proteases, (iii) uncompetitive inhibition with respect to substrate, and (iv) it does not shield calpain against inactivation by the active-site inhibitor trans-(epoxysuccinyl)-L-leucyl-amido-3-methylbutane, suggesting a nonactive site action for PD150606. The recombinant calcium-binding domain from each of the large or small subunits of mu-calpain was found to interact with PD150606. In low micromolar range, PD15O6O6 inhibited calpain activity in two intact cell systems. The neuroprotective effects of this class of compound were also demonstrated by the ability of PD150606 to attenuate hypoxic/hypoglycemic injury to cerebrocortical neurons in culture and excitotoxic injury to Purkinje cells in cerebellar slices.

Structural interactions between NOS-positive neurons and blood vessels in the hippocampus

The anatomical relationship between nitric oxide synthase (NOS)-positive neurons and blood vessels was examined in the hippocampus of the rat. NADPH-diaphorase histochemistry was used to identify NOS-positive neurons by light-microscopy. A close association of somatic, dendritic and axonal processes of NOS-positive neurons with cerebral blood vessels was observed. These findings suggest the possibility of neurovascular signaling by local NOS-containing neurons, through direct vascular innervation by terminals generating nitric oxide, and paracrine signaling from closely apposed somatic and dendritic neuronal elements.