Birds as bioindicators of plastic pollution in terrestrial and freshwater environments: A 30-year review

Plastic pollution is a global concern that has grown ever more acute in recent years. Most research has focused on the impact of plastic pollution in marine environments. However, plastic is increasingly being detected in terrestrial and freshwater environments with key inland sources including landfills, where it is accessible to a wide range of organisms. Birds are effective bioindicators of pollutants for many reasons, including their high mobility and high intra- and interspecific variation in trophic levels. Freshwater and terrestrial bird species are under-represented in plastic pollution research compared to marine species. We reviewed 106 studies (spanning from 1994 onwards) that have detected plastics in bird species dwelling in freshwater and/or terrestrial habitats, identifying knowledge gaps. Seventy-two studies focused solely on macroplastics (fragments >5 mm), compared to 22 microplastic (fragments <5 mm) studies. A further 12 studies identified plastics as both microplastics and macroplastics. No study investigated nanoplastic (particles <100 nm) exposure. Research to date has geographical and species' biases while ignoring nanoplastic sequestration in free-living freshwater, terrestrial and marine bird species. Building on the baseline search presented here, we urge researchers to develop and validate standardised field sampling techniques and laboratory analytical protocols such as Raman spectroscopy to allow for the quantification and identification of micro- and nanoplastics in terrestrial and freshwater environments and the species therein. Future studies should consistently report the internalised and background concentrations, types, sizes and forms of plastics. This will enable a better understanding of the sources of plastic pollution and their routes of exposure to birds of terrestrial and freshwater environments, providing a more comprehensive insight into the potential impacts on birds.

Maternal obesity and the human milk metabolome: associations with infant body composition and postnatal weight gain

BACKGROUND

Maternal obesity is a risk factor for childhood obesity; this is a major public health concern given that ∼40% of pregnant women are either overweight or obese. Whether differences in milk composition in lean compared with obese women contribute to childhood obesity is unclear.

OBJECTIVES

We aimed to analyze relationships between maternal obesity and human milk metabolites, infant body composition, and postnatal weight gain.

METHODS

This was a prospective study in which mothers intending to breastfeed exclusively, and their newborn infants, were enrolled at delivery (n = 35 mother-infant pairs). We excluded mothers with diabetes, other medical conditions, or pregnancy complications. Participants were grouped by maternal prepregnancy BMI <25 (lean) or ≥25 kg/m2 (overweight/obese). We analyzed infant body composition by dual-energy X-ray absorptiometry and used untargeted liquid chromatography-gas chromatography-mass spectrometry to measure the milk content of 275 metabolites at 1 and 6 mo postpartum.

RESULTS

At 1 mo postpartum, 10 metabolites differed between overweight/obese and lean groups with nominal P < 0.05, but none was altered with a false discovery rate <0.25. Many differentially abundant metabolites belonged to the same chemical class; e.g., 4/10 metabolites were nucleotide derivatives, and 3/10 were human milk oligosaccharides. Milk adenine correlated positively with both continuously distributed maternal BMI and with infant adiposity and fat accrual. Analysis of milk composition at 6 mo postpartum revealed 20 differentially abundant metabolites (P < 0.05) in overweight/obese compared with lean women, including 6 metabolites with a false discovery rate of <0.25. At both 1 and 6 mo, human milk abundance of 1,5-anhydroglucitol, which has not previously been described in milk, was positively associated with maternal BMI.

CONCLUSIONS

Maternal obesity is associated with changes in the human milk metabolome. While only a subset of metabolites correlated with both maternal and infant weight, these point to potential milk-dependent mechanisms for mother-child transmission of obesity. This trial was registered at www.clinicaltrials.gov as NCT02535637.

Educational Attainment of Mothers Aged 25 and Over: United States, 2017

Maternal education has been shown to be associated with the number of children a woman has during her childbearing years, as well as maternal and infant health (1-5). Using 2017 national birth certificate data, this report describes educational attainment of mothers aged 25 and over, overall and by race and Hispanic origin and state, and the mean numbers of live births by mothers' educational attainment.

Total Fertility Rates by State and Race and Hispanic Origin: United States, 2017

Objectives-This report presents 2017 total fertility rates by state of residence and race and Hispanic origin of mother for the United States. Methods-Data are from birth certificates of the 50 states and the District of Columbia. Total fertility rates, the expected number of lifetime births per 1,000 women given current birth rates by age, are shown by state for all births, and for non-Hispanic single-race white, non-Hispanic single-race black, and Hispanic women for 2017. Results-Total fertility rates varied by state for each race and Hispanic-origin group. In 2017, South Dakota (2,227.5) had the highest total fertility rate of the 50 states and the District of Columbia; the District of Columbia had the lowest (1,421.0). For non-Hispanic white women, the highest total fertility rate was in Utah (2,099.5) and the lowest in the District of Columbia (1,012.0). Among non-Hispanic black women, the highest total fertility rate was in Maine (4,003.5) and the lowest in Wyoming (1,146.0) along with California (1,503.5), Connecticut (1,575.5), Montana (1,641.0), New Mexico (1,651.0), New York (1,574.5), Rhode Island (1,594.0), and West Virginia (1,579.5). For Hispanic women, the highest total fertility rate was in Alabama (3,085.0) and the lowest in Vermont (1,200.5) and Maine (1,281.5).

Infant Mortality by Age at Death in the United States, 2016

Infant mortality is an important public health measure in the United States and other countries (1-3). The United States' infant mortality rate started to decline in 2007 (the most recent high), but has remained relatively unchanged in recent years (4,5). Previous research shows differences in infant mortality rates by age at death (i.e., neonatal, or deaths to infants aged 0-27 days, and postneonatal, or deaths to infants aged 28-364 days), age and race and Hispanic origin of the mother, and leading causes of death (4-6). This report examines infant mortality rates for the United States by age at death in 2016, by maternal age and race and Hispanic origin, and for the five leading causes of neonatal and postneonatal mortality.

Declines in Births to Females Aged 10-14 in the United States, 2000-2016

The birth rate for teen mothers aged 15-19 declined 57% from 2000 through 2016. During this time, the rate for young adolescent mothers aged 10-14 also declined. Childbearing by very young mothers is a matter of public concern because of the elevated health risks for these mothers and their infants and the socioeconomic consequences. This report describes recent trends and variations in births to young mothers aged 10-14 by race and Hispanic origin and state.

State Variations in Infant Mortality by Race and Hispanic Origin of Mother, 2013-2015

Infant mortality has long been a basic measure of public health for countries around the world (1–3). While the overall infant mortality rate in the United States is lower than a decade ago, declining 14% from 6.86 infant deaths per 1,000 live births in 2005, a recent high, to 5.90 in 2015, the rate in 2015 was not statistically different from that in 2014 (5.82) (4–6). The variability in infant mortality rates by state and by race and Hispanic origin continues to receive attention (7,8). This report uses linked birth and infant death data from 2013 through 2015 to describe infant mortality rates in the United States by state, and for race and Hispanic-origin groups by state.

Infant Mortality Rates in Rural and Urban Areas in the United States, 2014

The infant mortality rate is often used as a measure of a country’s health because similar factors influence population health and infant mortality (1). Although infant mortality has declined in the United States, disparities still exist across geographic areas and demographic groups (2–4). Urbanization level, based on the number and concentration of people in a county, can impact health outcomes (3–9). Previous research indicates that infant mortality rates vary by urbanization level and also by maternal and infant characteristics (3–9). This report describes differences in infant mortality among rural, small and medium urban, and large urban counties in the United States by infant’s age at death, mother’s age, and race and Hispanic origin in 2014.

Attenuated Effects of Bile Acids on Glucose Metabolism and Insulin Sensitivity in a Male Mouse Model of Prenatal Undernutrition

Prenatal undernutrition and low birth weight are associated with risk of type 2 diabetes and obesity. Prenatal caloric restriction results in low birth weight, glucose intolerance, obesity, and reduced plasma bile acids (BAs) in offspring mice. Because BAs can regulate systemic metabolism and glucose homeostasis, we hypothesized that BA supplementation could prevent diet-induced obesity and glucose intolerance in this model of developmental programming. Pregnant dams were food restricted by 50% from gestational days 12.5 to 18.5. Offspring of both undernourished (UN) and control (C) dams given unrestricted diets were weaned to high-fat diets with or without supplementation with 0.25% w/w ursodeoxycholic acid (UDCA), yielding four experimental groups: C, UN, C + UDCA, and UN + UDCA. Glucose homeostasis, BA composition, liver and intestinal gene expression, and microbiota composition were analyzed in the four groups. Although UDCA supplementation ameliorated diet-induced obesity in C mice, there was no effect in UN mice. UDCA similarly lowered fasting insulin, and improved glucose tolerance, pyruvate tolerance, and liver steatosis in C, but not UN, animals. BA composition differed significantly, and liver and ileal expression of genes involved in BA metabolism (Cyp7b1, Shp) were differentially induced by UDCA in C vs UN animals. Bacterial taxa in fecal microbiota correlated with treatment groups and metabolic parameters. In conclusion, prenatal undernutrition alters responsiveness to the metabolic benefits of BA supplementation, with resistance to the weight-lowering and insulin-sensitizing effects of UDCA supplementation. Our findings suggest that BA metabolism may be a previously unrecognized contributor to developmentally programmed diabetes risk.

Maternal obesity programs mitochondrial and lipid metabolism gene expression in infant umbilical vein endothelial cells

BACKGROUND/OBJECTIVES

Maternal obesity increases risk for childhood obesity, but molecular mechanisms are not well understood. We hypothesized that primary umbilical vein endothelial cells (HUVEC) from infants of overweight and obese mothers would harbor transcriptional patterns reflecting offspring obesity risk.

SUBJECTS/METHODS

In this observational cohort study, we recruited 13 lean (pre-pregnancy body mass index (BMI) <25.0 kg m^-2) and 24 overweight-obese ('ov-ob', BMI⩾25.0 kg m^-2) women. We isolated primary HUVEC, and analyzed both gene expression (Primeview, Affymetrix) and cord blood levels of hormones and adipokines.

RESULTS

A total of 142 transcripts were differentially expressed in HUVEC from infants of overweight-obese mothers (false discovery rate, FDR<0.05). Pathway analysis revealed that genes involved in mitochondrial and lipid metabolism were negatively correlated with maternal BMI (FDR<0.05). To test whether these transcriptomic patterns were associated with distinct nutrient exposures in the setting of maternal obesity, we analyzed the cord blood lipidome and noted significant increases in the levels of total free fatty acids (lean: 95.5±37.1 μg ml^-1, ov-ob: 124.1±46.0 μg ml^-1, P=0.049), palmitate (lean: 34.5±12.7 μg ml^-1, ov-ob: 46.3±18.4 μg ml^-1, P=0.03) and stearate (lean: 20.8±8.2 μg ml^-1, ov-ob: 29.7±17.2 μg ml^-1, P=0.04), in infants of overweight-obese mothers.

CONCLUSIONS

Prenatal exposure to maternal obesity alters HUVEC expression of genes involved in mitochondrial and lipid metabolism, potentially reflecting developmentally programmed differences in oxidative and lipid metabolism.

Smoking Prevalence and Cessation Before and During Pregnancy: Data From the Birth Certificate, 2014

OBJECTIVES

This report presents findings for 2014 on maternal smoking prevalence and cessation before and during pregnancy as collected on the 2003 U.S. Standard Certificate of Live Birth, for a 46-state and District of Columbia reporting area, representing 95% of all births in the United States.

METHODS

Cigarette smoking and cessation rates 3 months before and during pregnancy are presented by maternal age; race and ethnicity; marital status; educational attainment; source of payment at delivery (private insurance, Medicaid, and self-pay); receipt of benefits from the Special Supplemental Nutrition Program for Women, Infants, and Children; prenatal care initiation; and jurisdiction.

RESULTS

About 1 in 10 women who gave birth in 2014 smoked during the 3 months before pregnancy (10.9%), and about one-quarter of these women (24.2%) did not smoke during pregnancy (i.e., quit before pregnancy). The smoking rate at any time during pregnancy was 8.4%, with 20.6% of women who smoked in the first or second trimesters quitting by the third trimester. Smoking during pregnancy was more prevalent for women aged 20–24 (13.0%) than for other ages, and by race and Hispanic origin, the highest rate was for non- Hispanic American Indian or Alaska Native women (18.0%). Smoking during pregnancy ranged from 1.8% in California to 27.1% in West Virginia. The highest smoking cessation rates before and during pregnancy were for women with the highest educational attainment, private insurance, and non-Hispanic Asian and Hispanic race and ethnicity. On average, women who continued to smoke during pregnancy smoked fewer cigarettes as the pregnancy progressed, from 13 per day before pregnancy to 9 per day by the third trimester.

Births: Final Data for 2014

This report presents 2014 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, period of gestation, birthweight, and plurality. Birth and fertility rates are presented by age, live-birth order, race and Hispanic origin, and marital status. Selected data by mother's state of residence and birth rates by age and race of father also are shown. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

Infant Mortality Statistics From the 2013 Period Linked Birth/Infant Death Data Set

OBJECTIVES

This report presents 2013 period infant mortality statistics from the linked birth/infant death data set (linked file) by maternal and infant characteristics. The linked file differs from the mortality file, which is based entirely on death certificate data.

METHODS

Descriptive tabulations of data are presented and interpreted.

RESULTS

The U.S. infant mortality rate was 5.96 infant deaths per 1,000 live births in 2013, similar to the rate of 5.98 in 2012. The number of infant deaths was 23,446 in 2013, a decline of 208 infant deaths from 2012. From 2012 to 2013, infant mortality rates were stable for most race and Hispanic origin groups; declines were reported for two Hispanic subgroups: Cuban and Puerto Rican. Since 2005, the most recent high, the U.S. infant mortality rate has declined 13% (from 6.86), with declines in both neonatal and postneonatal mortality overall and for most groups. In 2013, infants born at 37–38 weeks of gestation (early term) had mortality rates that were 63% higher than for full-term (39–40 week) infants. For multiple births, the infant mortality rate was 25.84, 5 times the rate of 5.25 for singleton births. In 2013, 36% of infant deaths were due to preterm-related causes of death, and an additional 15% were due to causes grouped into the sudden unexpected infant death category.

Births: final data for 2013

OBJECTIVES

This report presents 2013 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, period of gestation, birthweight, and plurality. Birth and fertility rates are presented by age, live-birth order, race and Hispanic origin, and marital status. Selected data by mother's state of residence and birth rates by age and race of father also are shown. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

METHODS

Descriptive tabulations of data reported on the birth certificates of the 3.93 million U.S. births that occurred in 2013 are presented.

RESULTS

A total of 3,932,181 births were registered in the United States in 2013, down less than 1% from 2012. The general fertility rate declined to 62.5 per 1,000 women aged 15-44. The teen birth rate fell 10%, to 26.5 per 1,000 women aged 15-19. Birth rates declined for women in their 20s and increased for most age groups of women aged 30 and over. The total fertility rate (estimated number of births over a woman's lifetime) declined 1% to 1,857.5 per 1,000 women. Measures of unmarried childbearing were down in 2013 from 2012. The cesarean delivery rate declined to 32.7%. The preterm birth rate declined for the seventh straight year to 11.39%, but the low birthweight rate was essentially unchanged at 8.02%. The twin birth rate rose 2% to 33.7 per 1,000 births; the triplet and higher-order multiple birth rate dropped 4% to 119.5 per 100,000 total births.

International comparisons of infant mortality and related factors: United States and Europe, 2010

OBJECTIVES

This report investigates the reasons for the United States' high infant mortality rate when compared with European countries. Specifically, the report measures the impact on infant mortality differences of two major factors: the percentage of preterm births and gestational age-specific infant mortality rates.

METHODS

Infant mortality and preterm birth data are compared between the United States and European countries. The percent contribution of the two factors to infant mortality differences is computed using the Kitagawa method, with Sweden as the reference country.

RESULTS

In 2010, the U.S. infant mortality rate was 6.1 infant deaths per 1,000 live births, and the United States ranked 26th in infant mortality among Organisation for Economic Co-operation and Development countries. After excluding births at less than 24 weeks of gestation to ensure international comparability, the U.S. infant mortality rate was 4.2, still higher than for most European countries and about twice the rates for Finland, Sweden, and Denmark. U.S. infant mortality rates for very preterm infants (24-31 weeks of gestation) compared favorably with most European rates. However, the U.S. mortality rate for infants at 32-36 weeks was second-highest, and the rate for infants at 37 weeks of gestation or more was highest, among the countries studied. About 39% of the United States' higher infant mortality rate when compared with that of Sweden was due to a higher percentage of preterm births, while 47% was due to a higher infant mortality rate at 37 weeks of gestation or more. If the United States could reduce these two factors to Sweden's levels, the U.S. infant mortality rate would fall by 43%, with nearly 7,300 infant deaths averted annually.

Systematic review of congenital and acquired portal-systemic shunts in otherwise normal livers

BACKGROUND

Portal-systemic shunts (PSSs) are rarely seen in healthy individuals or patients with non-cirrhotic liver disease. They may play an important role in hepatic metabolism as well as in the spread of gastrointestinal metastatic tumours to specific organs. Small spontaneous PSSs may be more common than generally thought. However, epidemiological data are scarce and inconclusive. This systematic review examined the prevalence of reported PSSs and the associated detection methods.

METHODS

Literature up to 2011 was reviewed for adult patients with proven congenital or acquired PSSs. Only PSSs in normal livers were analysed for the methods of diagnosis. Eligible studies were identified by searching relevant databases, including PubMed, Embase, MEDLINE and the Cochrane Library. The selection of eligible articles was carried out using predefined inclusion criteria (adult, non-surgical PSS) and a set of search terms that were established before the articles were identified.

RESULTS

Eighty studies were included describing 112 patients with congenital or acquired PSSs. The majority were diagnosed incidentally using Doppler ultrasound imaging and CT.

CONCLUSION

Congenital and acquired PSSs are rare. They are usually clinically asymptomatic and discovered incidentally by radiological techniques. They may be clinically relevant owing to drug, tumour cell, metabolic and pathogen shunting.

National and state patterns of teen births in the United States, 1940-2013

OBJECTIVES

This report presents trends from 1940 through 2013 in national birth rates for teenagers, with particular focus on the period since 1991. The percent changes in rates for 1991-2012 and for 2007-2012 are presented for the United States and for states. Preliminary data for 2013 are shown where available.

METHODS

Tabular and graphical descriptions of the trends in teen birth rates for the United States and each state, by age group, race, and Hispanic origin, are presented and discussed. Data are shown for the U.S. territories.

RESULTS

Birth rates for U.S. teenagers have generally fallen in the United States since peaking in 1957. The rate fell 57% between 1991 and 2013. The 2013 preliminary rate (26.6 per 1,000 aged 15-19) is less than one-third of the historically highest rate (96.3 in 1957). During 1991-2012, rates fell for all race and Hispanic ethnicity groups, with the largest declines measured for non-Hispanic black teenagers. In the more recent period, 2007-2012, the declines have been steepest for Hispanic teenagers. Birth rates declined significantly for teenagers in all states during 1991-2012; during 2007-2012, rates fell for all but two states. The drop in teen birth rates translates into an estimated 4 million fewer births to teenagers from 1992 through 2012. The declines in teen birth rates reflect a number of behavioral changes, including decreased sexual activity, increases in the use of contraception at first sex and at most recent sex, and the adoption and increased use of hormonal contraception, injectables, and intrauterine devices.

First births to older women continue to rise

Data from the National Vital Statistics System The first birth rate for women aged 35-39 increased from 1970 to 2006, decreased from 2006 to 2010, and increased again in both 2011 and 2012. The first birth rate for women aged 40-44 was steady in the 1970s and started increasing in the 1980s. The rate more than doubled from 1990 to 2012. For women aged 35-39 and 40-44 all race and Hispanic origin groups had increasing first birth rates from 1990 to 2012. Since 2000, 46 states and DC had an increase in the first birth rate for women aged 35-39. For women aged 40-44, rates increased in 31 states and DC. The average age of women at first birth has risen over the past 4 decades (1-3). This increase is in part a reflection of the shift in first births to women 35 years and older. Delayed childbearing affects the size, composition, and future growth of the population in the United States (2). Increased health risks to older mothers, especially those 40 years and older, and their infants are well documented (4-7), first time older mothers are generally better educated and more likely to have more resources including higher incomes than those at the youngest reproductive ages (8). This report explores trends in first births to women aged 35-39 and 40-44 years from 1970 to 2012, and by race and Hispanic origin from 1990 to 2012 (the most recent year for which comparable data are available). Trends in first births for older women by state are examined for the recent period, 2000 to 2012.

Trends in out-of-hospital births in the United States, 1990-2012

Although still relatively rare, out-of-hospital births have accounted for a growing share of U.S. births since 2004. In 2012, 1.36% of U.S. births were born outside a hospital, up from 1.26% in 2011 and 0.87% in 2004. The 2012 level is the highest level since 1975. Most of the total increase in out-of-hospital births from 2004–2012 was a result of the increase among non-Hispanic white women, and by 2012, 1 in 49 births to non-Hispanic white women (2.05%) occurred outside a hospital. In 2012, six states had 3%–6% of their births occur outside a hospital. For an additional five states, between 2% and 3% of their births were out-of-hospital births. Variations in the percentages of out-of-hospital births by state may be influenced by differences in state laws pertaining to midwifery practice or out-of-hospital births, as well as by the availability of a nearby birthing center. The number of U.S. birthing centers increased from 170 in 2004 to 195 in 2010 and to 248 in January 2013; 13 states still did not have a birthing center in the most recent period. Compared with hospital births, home and birthing center births tended to have lower risk profiles, with fewer births to teen mothers and fewer preterm, low birthweight, and multiple births. From 2004 through 2012, there was a decline in the risk profile of out-of-hospital births, with fewer births in 2012 than in 2004 to teen and older mothers and fewer preterm and low birthweight births. The lower risk profile of out-of-hospital than hospital births suggests that appropriate selection of low-risk women as candidates for out-of-hospital birth is occurring. Although not representative of all U.S. births, 88% of home births in a 36-state reporting area (comprising 71% of U.S. births) were planned in 2012. Unplanned home births are more likely than planned home births to be born preterm and at low birthweight.

Births: final data for 2012

OBJECTIVES

This report presents 2012 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, period of gestation, birthweight, and plurality. Birth and fertility rates are presented by age, live-birth order, race and Hispanic origin, and marital status. Selected data by mother's state of residence and birth rates by age and race of father also are shown. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

METHODS

Descriptive tabulations of data reported on the birth certificates of the 3.95 million births that occurred in 2012 are presented.

RESULTS

A total of 3,952,841 births were registered in the United States in 2012. The general fertility rate declined to 63.0 per 1,000 women aged 15-44. The teen birth rate fell 6%, to 29.4 per 1,000 women. Birth rates declined for women in their twenties and increased for women aged 30-44. The total fertility rate (estimated number of births over a woman's lifetime) declined 1% to 1,880.5 per 1,000 women. The rate of births to unmarried women declined; the percentage of births to unmarried women was essentially stable at 40.7%, but the number of births to unmarried women increased slightly. The cesarean delivery rate was unchanged at 32.8%. The preterm birth rate declined for the sixth straight year to 11.55%; the low birthweight rate declined slightly to 7.99%. The twin birth rate was stable at 33.1 per 1,000 births; the rate of triplet and higher-order multiple births dropped 9% to 124.4 per 100,000 total births.

Infant mortality statistics from the 2010 period linked birth/infant death data set

OBJECTIVES

This report presents 2010 period infant mortality statistics from the linked birth/infant death data set (linked file) by maternal and infant characteristics. The linked file differs from the mortality rate declined mortality file, which is based entirely on death certificate data.

METHODS

Descriptive tabulations of data are presented and interpreted.

RESULTS

The U.S. infant mortality rate was 6.14 infant deaths per 1,000 live births in 2010, 4% lower than the rate of 6.39 in 2009. The number of infant deaths was 24,572 in 2010, a decline of 1,836 infant deaths from 2009. From 2009 to 2010, the infant mortality rate declined 8% for non-Hispanic black mothers to 11.46, and 3% for non-Hispanic white mothers to 5.18. Asian or Pacific Islander mothers had the lowest rate in 2010 (4.27). From 2009 to 2010, the neonatal mortality rate declined by 3% to 4.05 neonatal deaths per 1,000 live births, while the postneonatal mortality rate declined 5% to 2.10. In 2010, infants born at 37-38 weeks of gestation (early term) had infant mortality rates that were 62% higher than those born at 39-41 weeks of gestation. For multiple births, the infant mortality rate was 25.41, almost five times the rate of 5.45 for singleton births. The three leading causes of infant death-congenital malformations, low birthweight, and sudden infant death syndrome-accounted for 46% of all infant deaths. In 2010, 35.2% of infant deaths were preterm-related.

Newly released data from the revised U.S. birth certificate, 2011

OBJECTIVES

This report is the first release of multistate data for selected items exclusive to the 2003 revision of the U.S. Standard Certificate of Live Birth. Included is information for prepregnancy body mass index, smoking and quitting smoking in the 3 months prior to pregnancy, receipt of food from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) during pregnancy, pregnancy resulting from infertility treatment, source of payment for delivery, and maternal morbidities.

METHODS

Descriptive statistics are presented for 100% of 2011 births to residents of the 36 states, the District of Columbia (D.C.), and Puerto Rico that had implemented the revised birth certificate by January 1, 2011. This reporting area is not a random sample, and results are not generalizable to the United States as a whole.

RESULTS

The 3,267,934 births to residents of the 36-state and D.C. reporting area represented 83% of all 2011 U.S. births. Levels of prepregnancy obesity ranged from 18.0% in Utah to 28.6% in South Carolina. Hispanic women were the least likely to smoke in the 3 months prior to pregnancy and were the most likely to quit smoking prior to pregnancy. Women under age 20 were more than twice as likely to receive WIC food during pregnancy as women aged 35 and over in nearly all states and D.C. The percentage of births resulting from infertility treatment ranged from 0.3% in New Mexico to over 3.5% in Maryland and Utah. The percentage of deliveries covered by Medicaid ranged from 28.8% in North Dakota to 64.2% in Louisiana.

Review of bubble detector response characteristics and results from space

A passive neutron-bubble dosemeter (BD), developed by Bubble Technology Industries, has been used for space applications. Both the bubble detector-personal neutron dosemeter and bubble detector spectrometer have been studied at ground-based facilities in order to characterise their response due to neutrons, heavy ion particles and protons. This technology was first used during the Canadian-Russian collaboration aboard the Russian satellite BION-9, and subsequently on other space missions, including later BION satellites, the space transportation system, Russian MIR space station and International Space Station. This paper provides an overview of the experiments that have been performed for both ground-based and space studies in an effort to characterise the response of these detectors to various particle types in low earth orbit and presents results from the various space investigations.

Yoked variable-ratio and variable-interval responding in pigeons

Pigeons' key pecks were maintained by variable-ratio or variable-interval schedules of food reinforcement. For pairs of pigeons in one group, variable-ratio reinforcement was arranged for one pigeon's pecks; for the second pigeon, reinforcement was arranged according to a variable-interval schedule yoked to the interreinforcement times produced by the first pigeon. For pairs of pigeons in another group, variable-interval reinforcement was arranged for one pigeon's pecks; for the second pigeon, reinforcement was arranged according to a variable-ratio schedule yoked to the interreinforcement responses produced by the first pigeon. For each pair, the yoking procedure was maintained for four or five consecutive sessions of 50 reinforcements each. In more than three-quarters of the pairs, variable-ratio response rates were higher than variable-interval rates within two sessions; in all cases, the rate difference developed within four sessions.

Delayed childbearing: more women are having their first child later in life

Of particular interest to both researchers and the public is the "average" age of women when they have a child, especially their first. Age at first birth influences the total number of births that a woman might have in her life, which impacts the size, composition, and future growth of the population. The age of the mother, both younger and older, plays a strong role in a wide range of birth outcomes (e.g., birthweight, multiple births, and birth defects), so it is critical to track the average age at which women have their first birth.

Characterization of envelope glycoprotein gp41 genotype and phenotypic susceptibility to enfuvirtide at baseline and on treatment in the phase III clinical trials TORO-1 and TORO-2

Enfuvirtide (T-20) is the first entry inhibitor approved for treatment of HIV infection and acts by inhibiting conformational changes in the viral envelope protein gp41 that are necessary for fusion of the virus and host cell membranes. Here we present genotypic and phenotypic data on viral envelopes obtained at baseline (n = 627) and after 48 weeks of enfuvirtide treatment (n = 302) from patients in the TORO (T-20 versus Optimized Regimen Only)-1 and -2 phase III pivotal studies. The amino acid sequence at residues 36-45 of gp41 was highly conserved at baseline except for polymorphism of approximately 16% at position 42. Substitutions within gp41 residues 36-45 on treatment were observed in virus from 92.7% of patients who met protocol defined virological failure criteria and occurred in nearly all cases (98.8%) when decreases in susceptibility to enfuvirtide from baseline of greater than 4-fold were observed. Consistent with previous observations, a wide range of baseline susceptibilities (spanning 3 logs) was observed; however, lower in vitro baseline susceptibility was not significantly associated with a decreased virological response in vivo. Virological response was also independent of baseline coreceptor tropism and viral subtype.

The role of the third beta strand in gp120 conformation and neutralization sensitivity of the HIV-1 primary isolate DH012

Neutralization of HIV-1 primary isolates has been a tremendous challenge for AIDS vaccine development. Here, we identify a single amino acid change (T198P) in gp120 that alters the neutralization sensitivity of the primary isolate DH012 to antibodies against multiple neutralization epitopes that include the V3, CD4-induced, and CD4 binding sites in gp120. This mutation is located in the V1/V2 stem region that forms the third beta strand (beta3) of the bridging sheet of gp120. The conformation of variable loops, especially V1/V2 and V3, was proposed to regulate the accessibility of these neutralization epitopes. The results of this study indicate a direct association between the V1/V2 and V3 loops of DH012 gp120. The single amino acid mutation T198P in the beta3 severely compromises the interaction between the V1/V2 and V3 loops. These results suggest that interaction of V1/V2 and V3 can mask the neutralization epitopes and that the beta3 plays a critical role in determining the neutralization sensitivity by modulating the interaction. This study provides an insight into why primary isolates are relatively resistant to antibody neutralization and might facilitate the development of anti-HIV strategies against HIV-1 infection.

Induction and characterization of neutralizing antibodies against a human immunodeficiency virus type 1 primary isolate

Chimpanzees infected with the primary isolate DH012 mount potent neutralizing antibodies. This DH012 neutralizing activity is highly strain specific. Immune sera from guinea pigs immunized with recombinant DH012 gp120 could also neutralize this primary isolate. The neutralizing activity in chimpanzee and guinea pig sera against wild-type DH012 appears to be independent of a linear epitope in the V3 region of gp120. Interestingly, the neutralization escape mutant derived from growing DH012 in the presence of the potent neutralizing chimpanzee serum is at least 50-fold more sensitive than wild-type DH012 to neutralization by guinea pig immune sera. The unusually potent neutralizing activity against the DH012 neutralization-resistant virus is due to the presence of anti-V3 antibodies in guinea pig sera. These results suggested that recombinant gp120 could induce neutralizing antibodies against primary isolate DH012. The V3 of wild-type DH012 is poorly immunogenic in infected chimpanzees and is not accessible to neutralizing V3 antibodies. It is likely that this cryptic V3 region became exposed when the virus escaped the neutralizing activity of the chimpanzee serum.

Digital imaging of surgical specimens using a wet scanning technique

AIM

To develop a simple method of recording digital images of surgical specimens on to a personal computer (PC) for use in presentations for teaching and reporting of their pathology.

METHODS

A perspex box was constructed to international A4 size 100 mm deep. This box had a base of 3 mm clear perspex with sides and top of 5 mm white perspex. This box was partially filled with distilled water and a specimen immersed in it. It was then placed on top of a standard A4 scanner. The specimen was then scanned into a PC using image capture software.

RESULTS

The images produced showed noticeable improvement over normal photographs, especially with specimens prone to wet highlights.

CONCLUSIONS

The method has proved to be a rapid and efficient means of producing macroscopic images of surgical specimens.

Role of human immunodeficiency virus (HIV) type 1 envelope in the anti-HIV activity of the betulinic acid derivative IC9564

The betulinic acid derivative IC9564 is a potent anti-human immunodeficiency virus (anti-HIV) compound that can inhibit both HIV primary isolates and laboratory-adapted strains. However, this compound did not affect the replication of simian immunodeficiency virus and respiratory syncytial virus. Results from a syncytium formation assay indicated that IC9564 blocked HIV type 1 (HIV-1) envelope-mediated membrane fusion. Analysis of a chimeric virus derived from exchanging envelope regions between IC9564-sensitive and IC9564-resistant viruses indicated that regions within gp120 and the N-terminal 25 amino acids (fusion domain) of gp41 are key determinants for the drug sensitivity. By developing a drug-resistant mutant from the NL4-3 virus, two mutations were found within the gp120 region and one was found within the gp41 region. The mutations are G237R and R252K in gp120 and R533A in the fusion domain of gp41. The mutations were reintroduced into the NL4-3 envelope and analyzed for their role in IC9564 resistance. Both of the gp120 mutations contributed to the drug sensitivity. On the contrary, the gp41 mutation (R533A) did not appear to affect the IC9564 sensitivity. These results suggest that HIV-1 gp120 plays a key role in the anti-HIV-1 activity of IC9564.

Monoclonal antibodies that bind to the core of fusion-active glycoprotein 41

The heptad repeat regions HR1 and HR2 of HIV-1 gp41 can associate to form heterooligomers through helical coil-coil interactions that are believed to play a key role in virus-induced membrane fusion. The HR1/HR2 complex was proposed to be the core structure of the fusion-active conformation of gp41. Here, we show that two human monoclonal antibodies, Fab-d and 50-69, specifically recognize the putative fusion-active conformation of gp41. Fab-d binding requires the interaction between the HR1 and HR2 regions of gp41. The reactivity of human monoclonal antibody 50-69 to the C terminus of the HR1 sequence is dependent on the helical structure of HR1. It appears that HR2 is able to interact with HR1 and, subsequently, induce an epitope in HR1 that is required for 50-69 binding. Mutations that disrupt the helical structure of HR1 significantly compromise Fab-d and 50-69 binding. Although the epitopes are not identical, the ability of Fab-d to partially compete with 50-69 binding suggests a close proximity of the two epitopes. Antibodies that are able to interact with the core of the putative fusion-active gp41 may be useful in further unveiling the mechanism of HIV-induced membrane fusion.

Heptad-repeat regions of respiratory syncytial virus F1 protein form a six-membered coiled-coil complex

The Respiratory Syncytial Virus (RSV) fusogenic glycoprotein F(1) was characterized using biochemical and biophysical techniques. Two heptad-repeat (HR) regions within F(1) were shown to interact. Proteinase-K digestion experiments highlight the HR1 region (located proximal to the fusion peptide sequence) of the F(1) protein to which an HR2-derived (located proximal to the membrane-spanning domain) peptide binds, thus protecting both the protein and peptide from digestion. Solution-phase analysis of HR1-derived peptides shows that these peptides adopt helical secondary structure as measured by circular dichroism. Sedimentation equilibrium studies indicate that these HR1 peptides self-associate in a monomer/trimer equilibrium with an association constant of 5.2 x 10(8) M(-2). In contrast, HR2-derived peptides form random monomers in solution. CD analysis of mixtures containing peptides from the two regions demonstrate their propensity to interact and form a very stable (T(m) = 87 degrees C), helical (86% helicity) complex comprised of three HR1 and three HR2 members.

Determinants of CD4 independence for a human immunodeficiency virus type 1 variant map outside regions required for coreceptor specificity

Although infection by human immunodeficiency virus (HIV) typically requires an interaction between the viral envelope glycoprotein (Env), CD4, and a chemokine receptor, CD4-independent isolates of HIV and simian immunodeficiency virus have been described. The structural basis and underlying mechanisms for this phenotype are unknown. We have derived a variant of HIV-1/IIIB, termed IIIBx, that acquired the ability to utilize CXCR4 without CD4. This virus infected CD4-negative T and B cells and fused with murine 3T3 cells that expressed human CXCR4 alone. A functional IIIBx env clone exhibited several mutations compared to the CD4-dependent HXBc2 env, including the striking loss of five glycosylation sites. By constructing env chimeras with HXBc2, the determinants for CD4 independence were shown to map outside the V1/V2 and V3 hypervariable loops, which determine chemokine receptor specificity, and at least partly within an area on the gp120 core that has been implicated in forming a conserved chemokine receptor binding site. We also identified a point mutation in the C4 domain that could render the IIIBx env clone completely CD4 dependent. Mutations in the transmembrane protein (TM) were also required for CD4 independence. Remarkably, when the V3 loop of a CCR5-tropic Env was substituted for the IIIBx Env, the resulting chimera was found to utilize CCR5 but remained CD4 independent. These findings show that Env determinants for chemokine receptor specificity are distinct from those that mediate CD4-independent use of that receptor for cell fusion and provide functional evidence for multiple steps in the interaction of Env with chemokine receptors. Combined with our observation that the conserved chemokine receptor binding site on gp120 is more exposed on the IIIBx gp120 (T. L. Hoffman, C. C. LaBranche, W. Zhang, G. Canziani, J. Robinson, I. Chaiken, J. A. Hoxie, and R. W. Doms, Proc. Natl. Acad. Sci. USA 96:6359-6364, 1999), the findings from this study suggest novel approaches to derive and design Envs with exposed chemokine receptor binding sites for vaccine purposes.

Engineering of noninfectious HIV-1-like particles containing mutant gp41 glycoproteins as vaccine candidates that allow vaccinees to be distinguished from HIV-1 infectees

Many AIDS vaccine candidates under development may elicit immune responses similar to those observed in and used to screen human immunodeficiency virus type 1 (HIV-1)-infected individuals. Therefore, it is important to develop vaccine candidates that incorporate antigenic markers and allow vaccinees to be distinguished from HIV-1 infectees. To this end, we introduced a series of mutations into and in the vicinity of the major immunodominant region (MIR) of gp41 (residues 598-609), a domain recognized by almost all HIV-1 infectees, and evaluated whether HIV-1-like particles incorporating such mutant glycoproteins could be expressed in mammalian cells. Results indicated that although up to three consecutive amino acids could be replaced within MIR without significantly affecting particle formation or gp160 processing, deletions within MIR impaired envelope processing. Replacement of HIV-1 MIR by part or most of the corresponding domain from other lentiviruses markedly decreased or abolished gp160 processing. Synthetic peptides corresponding to a mutated MIR incorporating three amino acid replacements were not recognized by a panel of sera from HIV-1 infectees, suggesting that HIV-1-like particles with this type of mutation represent potential candidate vaccines that could allow vaccinees to be distinguished from HIV-1 infectees.

Safety and immunogenicity of a live recombinant canarypox virus expressing HIV type 1 gp120 MN MN tm/gag/protease LAI (ALVAC-HIV, vCP205) followed by a p24E-V3 MN synthetic peptide (CLTB-36) administered in healthy volunteers at low risk for HIV infection. AGIS Group and L'Agence Nationale de Recherches sur Le Sida

A live recombinant canarypox vector expressing HIV-1 gpl20 MN tm/gag/protease LAI (ALVAC-HIV, vCP205) alone or boosted by a p24E-V3 MN synthetic peptide (CLTB-36) was tested in healthy volunteers at low risk for HIV infection for their safety and immunogenicity. Both antigens were well tolerated. ALVAC-HIV (vCP205) induced low levels of neutralizing antibodies against HIV-1 MN in 33% of the volunteers. None of them had detectable neutralizing antibodies against a nonsyncytium-inducing HIV-1 clade B primary isolate (Bx08). After the fourth injection of vCP205, CTL activity was detected in 33% of the volunteers and was directed against Env, Gag, and Pol. This activity was mediated by both CD4+ and CD8+ lymphocytes. On the other hand, the CLTB-36 peptide was poorly immunogenic and induced no neutralizing antibodies or CTLs. Although the ALVAC-HIV (vCP205) and CLTB-36 prime-boost regimen was not optimal, further studies with ALVAC-HIV (vCP205) are warranted because of its clear induction of a cellular immune response and utility as a priming agent for other subunit antigens such as envelope glycoproteins, pseudoparticles, or new peptides.

HIV-1MN recombinant glycoprotein 160 vaccine-induced cellular and humoral immunity boosted by HIV-1MN recombinant glycoprotein 120 vaccine. National Institute of Allergy and Infectious Diseases AIDS Vaccine Evaluation Group

We evaluated prime-boost immunization with two recombinant envelope glycoprotein subunit vaccines (HIV-1MN recombinant gp160 vaccine in alum adjuvant [MN rgp160] and HIV-1MN recombinant gp120 vaccine in alum adjuvant [MN rgp120]) for safety and immunogenicity in healthy, HIV-1-uninfected adults. The rationale was to combine the helper T cell memory and binding antibody responses typically induced by rgp160 vaccines with the superior neutralizing antibody responses induced by rgp120 vaccines. In a double-blinded, controlled trial, volunteers were randomly assigned to receive MN rgp160 or adjuvant placebo, and a subset later received MN rgp120. The two vaccines were safe, but reactions to MN rgp160 and its adjuvant placebo exceeded those to MN rgp120. MN rgp160 induced IgG binding antibodies, including all IgG subclasses, to MN rgp160 in all vaccine recipients. HIV-1MN-neutralizing and anti-V3 MN peptide-binding antibodies were observed in a majority of volunteers after the fourth MN rgp160 immunization, but at lower levels compared with immunization with MN rgp120 in historical controls. HIV-1-binding, neutralizing, and fusion inhibition antibodies were boosted to the highest levels among MN rgp160 recipients after MN rgp120 booster injections. MN rgp120 boosting appeared to alter the distribution of MN rgp160 vaccine-induced, anti-MN rgp160 IgG subclass antibodies. MN rgp160 induced helper T cell memory, measured by lymphocyte proliferation, Thl and Th2 cytokine production, and skin testing. Strategies including both subunit vaccines may help maximize antibody and helper T cell memory responses to HIV-1 envelope glycoprotein.

Nuclear magnetic resonance analysis of solution conformations in C4-V3 hybrid peptides derived from human immunodeficiency virus (HIV) type 1 gp120: relation to specificity of peptide-induced anti-HIV neutralizing antibodies

Immunogenic peptides containing epitopes of the gp120 C4 and V3 regions from human immunodeficiency virus strains MN and EV91 have been studied by nuclear magnetic resonance and molecular modeling and used as immunogens in rhesus monkeys. The results, combined with those for other peptides, suggest a correlation between solution conformation and immunologic cross-reactivity.

CD4-independent utilization of the CXCR4 chemokine receptor by HIV-1 and HIV-2

HIV entry is mediated by an interaction between CD4 and members of the chemokine receptor family of proteins. It is likely that CD4 induces conformational changes in the viral envelope glycoproteins that facilitate a subsequent interaction with the chemokine receptor. To understand these events, variants of HIV-2 and HIV-1 have been derived that are able to interact directly with CXCR4 in the absence of CD4. One HIV-2 variant. termed HIV-2/vcp, has an expanded host range that includes CXCR4+/CD4- lymphoid and nonlymphoid cell lines. In contrast to T-tropic isolates of HIV-1, HIV-2/vcp was shown to induce > 95% downregulation of CXCR4 on chronically infected cells and was able to superinfect HIV-1-infected cells. A variant of HIV-1/IIIB termed HIV-1/IIIBx was also derived that is both replication competent and fusogenic for a CD4-negative subclone of SupT1 cells, termed BC7. Infection of BC7 cells by HIV-1/IIIBx was resistant to anti-CD4 monoclonal antibodies but inhibited by the anti-CXCR4 mAb, 12G5. HIV-1/IIIBx was highly fusogenic on 3T3 cells expressing CXCR4 in the absence of CD4. In contrast to HIV-2/vcp, the host range of HIV-1/IIIBx was highly restricted and replication in several CD4+/CXCR4+ lymphoid cell lines was reduced compared to HIV-1/IIIB. In addition, HIV-1/IIIBx failed to downregulate CXCR4 on chronically infected cells. These studies indicate that HIV-1 and HIV-2 variants can be derived in vitro that utilize CXCR4 in the absence of CD4. Although the mechanism(s) for these changes remain unclear, possibilities include an increased avidity of the viral envelope glycoprotein for CXCR4 and/or the increased exposure of the chemokine receptor binding site. Further biochemical and molecular analysis of the envelope glycoproteins from these viruses should be helpful in addressing these and other possibilities.

Immune responses to human immunodeficiency virus (HIV) type 1 induced by canarypox expressing HIV-1MN gp120, HIV-1SF2 recombinant gp120, or both vaccines in seronegative adults. NIAID AIDS Vaccine Evaluation Group

A safety and immunogenicity trial was conducted in vaccinia-immune and vaccinia-naive human immunodeficiency virus (HIV)-uninfected adults who were randomized to receive 10(6) or 10(7) TCID50 of canarypox (ALVAC) vector expressing HIV-1MN gp160 or 10(5.5) TCID50 of ALVAC-rabies virus glycoprotein control at 0 and 1 or 2 months and ALVAC-gp160 or 50 microg of HIV-1SF2 recombinant (r) gp120 in microfluidized emulsion at 9 and 12 months; others received rgp120 at 0, 1, 6, and 12 months. All vaccines were well-tolerated. Neither vaccinia-immune status before vaccination nor ALVAC dose affected HIV immune responses. HIV-1MN and HIV-1SF2 neutralizing antibodies were detected more often (100%) in ALVAC-gp160/rgp120 recipients than in recipients of ALVAC-gp160 (<65%) or rgp120 (89%) alone. ALVAC-gp160/rgp120 also elicited more frequent HIV V3-specific and fusion-inhibition antibodies, antibody-dependent cellular cytotoxicity, lymphoproliferation, and cytotoxic CD8+ T cell activity than did either vaccine alone. Trials with ALVAC expressing additional HIV components and rgp120 are underway.

Modulation of immunologic responses to HIV-1MN recombinant gp160 vaccine by dose and schedule of administration. National Institute of Allergy and Infectious Diseases AIDS Vaccine Evaluation Group

The safety and immunogenicity of HIV-1MN recombinant gp160 (MN rgp160) vaccine in healthy, uninfected volunteers was tested in a double-blind study with a factorial design. By random assignment, 20 volunteers received three 200 micrograms doses of MN rgp160 and four volunteers received placebo at days 0, 28, and 168 or 0, 56, and 224. Of the 24 volunteers, 16 received 200 micrograms or 800 micrograms of MN rgp160 and two received placebo at day 532 (month 18). The vaccine was safe. It induced T cell memory measured by Th1 cytokine production and lymphocyte proliferation, and serum anti-MN rgp160 IgG (all subclasses) and IgA antibodies. Fifteen of 20 vaccinees developed neutralizing antibody. The regimen including immunizations on days 0, 28, and 168 followed by the 800 micrograms fourth dose was most immunogenic.

Births of Hispanic origin, 1989-95

OBJECTIVES

This report presents trend data on births in the United States to women of Hispanic and non-Hispanic origin, from 1989 to 1995, for a wide variety of characteristics. Hispanic women data are presented where possible separately for Mexican, Puerto Rican, Cuban, Central and South American, and other Hispanic women while for non-Hispanic women data are shown for white and black women. Maternal demographic characteristics include age, marital status, live-birth order, educational attainment, and mother's place of birth. Health care utilization items include timing of prenatal care, cesarean delivery rate, place of birth and midwife attendance. Infant health characteristics include percents born preterm, low birthweight, very low birthweight, and percent born in multiple births. Trend data for the number of births by State are also presented.

METHODS

Descriptive tabulations of births of Hispanic origin of the mother for births that occurred from 1989 through 1995 are presented.

RESULTS

The number of births born to Hispanic women has risen every year from 1989 to 1995. In addition in 1989 Hispanic women had 14 percent of births in the United States and in 1995 they represented 18 percent. While Hispanic women as a group continue to have higher fertility rates than non-Hispanics, Mexican women in particular have dramatically higher rates. While increases in early prenatal care were observed for all women in the United States, increases were particularly substantial for Hispanic women. The cesarean section rate has been dropping in the United States; yet while rates for Cuban women have also been dropping, the rates are nearly 50 percent higher than those for any other population subgroup.

Analysis of intercurrent human immunodeficiency virus type 1 infections in phase I and II trials of candidate AIDS vaccines. AIDS Vaccine Evaluation Group, and the Correlates of HIV Immune Protection Group

Among 2099 uninfected subjects in phase I and II trials of candidate AIDS vaccines, 23 were diagnosed with intercurrent human immunodeficiency virus type 1 (HIV-1) infection. High-risk sexual exposures accounted for 17 infections, and intravenous drug use accounted for 6. Four subjects received placebo, 13 received a complete immunization schedule (> or = 3 injections), and 6 were partially immunized (< or = 2 injections). There was no significant difference between vaccine recipients and control groups in incidence of HIV-1 infection, virus load, CD4 lymphocyte count, or V3 loop amino acid sequence. In summary, 19 vaccinated subjects acquired HIV-1 infection during phase I and II trials, indicating that immunization with the products described is < 100% effective in preventing or rapidly clearing infection. Laboratory analysis suggested that vaccine-induced immune responses did not significantly affect the genotypic or phenotypic characteristics of transmitted virus or the early clinical course of HIV-1 infection.

Determinants of human immunodeficiency virus type 1 resistance to gp41-derived inhibitory peptides

A synthetic peptide, DP178, containing amino acids 127 to 162 of the human immunodeficiency virus type 1 (HIV-1) gp41 Env glycoprotein, is a potent inhibitor of virus infection and virus mediated cell-to-cell fusion (C. Wild, T. Greenwell, and T. Matthews, AIDS Res. Hum. Retroviruses 9:1051-1053, 1993). In an effort to understand the mechanism of action of this peptide, we derived resistant variants of HIV-1(IIIB) and NL4-3 by serial virus passage in the presence of increasing doses of the peptide. Sequence analysis of the resistant isolates suggested that a contiguous 3-amino-acid sequence within the amino-terminal heptad repeat motif of gp41 was associated with resistance. Site-directed mutagenesis studies confirmed this observation and indicated that changes in two of these three residues were necessary for development of the resistant phenotype. Direct binding of DP178 to recombinant protein and synthetic peptide analogs containing the wild-type and mutant heptad repeat sequences revealed a strong correlation between DP178 binding and the biological sensitivity of the corresponding virus isolates to DP178. The results are discussed from the standpoints of the mechanism of action of DP178 and recent crystallographic information for a core structure of the gp41 ectodomain.

Sexual reinforcement in the female rat

Sexual reinforcement in the female rat was studied in a preparation that allowed continuous operant responding for access to a male rat leading to intromission. Experiment 1 used a high operant level nose-poke response to test the possible reinforcing effects of some components of access to a male. A simple tone stimulus used as a conditioned reinforcer and two odor stimuli, target male bedding and emulsified preputial gland, were tested. None of these contingent events altered responding above or below operant level. Access to the male, which was always accompanied by intromission, immediately increased response rate when it was made contingent upon the nose-poke response. Performance on fixed-ratio schedules was erratic, and response rate was low in comparison to typical food-reinforced responding. An interresponse-time analysis indicated, however, that some effect of the ratio contingency may have been present. In Experiment 2, several modifications of the procedure were tested with the objective of creating a more tractable preparation for behavior analysis. Response type and the hormone delivery method were changed, and 2 target males were used instead of 1. The latter tripled the average number of reinforcers earned in a single session. Differences between sexual and other reinforcers are discussed in terms of procedural, quantitative, and motivational aspects of the sexual reinforcement procedure.

Identification of a synthetic peptide that mimics an HIV glycoprotein 120 envelope conformational determinant exposed following ligation of glycoprotein 120 by CD4

CD4 ligation of HIV envelope gp120 results in conformational changes in gp120 that lead to exposure of the gp41 fusogenic domain and fusion with the host cell membrane. One determinant at or near the CD4-binding site exposed on gp120 subsequent to CD4 binding is defined by two human MAbs termed 17b and 48d. These MAbs do not block CD4 binding to gp120; rather, their binding to gp120 is upregulated following CD4 binding. To determine if synthetic peptide mimetopes could be found that reflect conformational determinants on the surface of gp120, synthetic gp120 peptides from 10 divergent HIV isolates were screened for their ability to bind to 17b and 48d in ELISAs. Although MAb 48d binds to HIV IIIB recombinant gp120 protein, in our studies 48d selectively bound only to the HIV Can0A V3 peptide and not to HIV IIIB V3 peptide, whereas MAb 17b bound none of the peptides tested. Monoclonal antibody 48d bound to the HIV Can0A V3 peptide both in solid-phase ELISA and in solution in a competitive ELISA, but could not bind to HIV Can0A V3 peptide bound to human T cells. The HIV Can0A V3 peptide induced anti-HIV antibodies in rhesus monkeys that neutralized the laboratory-adapted HIV MN strain but did not induce antibodies that neutralized HIV IIIB/LAI, HIV SF-2, or HIV RF isolates, or that neutralized HIV primary isolates. These data suggested that the primary sequence of the HIV Can0A V3 loop exists in a conformer that mimicks a non-V3 determinant of native gp120 exposed subsequent to CD4 binding on the surface of gp120 of laboratory-adapted HIV strains. Structural studies of the Can0A V3 peptide and/or the 48d MAb may provide important information regarding the nature of gp120 conformational changes that occur following gp120 ligation by CD4.

Safety and immunogenicity of a candidate HIV-1 vaccine in healthy adults: recombinant glycoprotein (rgp) 120. A randomized, double-blind trial. NIAID AIDS Vaccine Evaluation Group

OBJECTIVE

To evaluate the safety and immunogenicity of recombinant glycoprotein (rgp) 120, a candidate vaccine for the human immunodeficiency virus (HIV), formulated with a novel adjuvant, MF59, with or without a biological response modifier, MTP-PE.

DESIGN

Multicenter, double-blind, randomized trial.

SETTING

University medical centers.

PARTICIPANTS

49 healthy, HIV-seronegative volunteers 18 to 60 years of age who were at low risk for HIV type 1 (HIV-1) infection.

INTERVENTIONS

In part A of the study, 32 participants were randomly assigned to receive either 15 micrograms of rgp 120 in MF59, 15 micrograms of rgp 120 in MF59 plus 50 micrograms of MTP-PE, 50 micrograms of rgp 120 in MF59, or 50 micrograms of rgp 120 in MF59 plus 50 micrograms of MTP-PE. Participants were vaccinated at 0, 1, 6, and 12 to 18 months. In part B, 17 participants were randomly assigned to receive five monthly injections of either 50 micrograms of rgp 120 in MF59 or MF59 alone followed by a booster injection at 12 to 18 months.

MAIN OUTCOME MEASURES

Local and systemic reactions; laboratory measures of hepatic, renal, immunologic, and bone marrow toxicity; and HIV-specific serologic and cell-mediated immune responses.

RESULTS

13 patients in part A received 50-micrograms doses of rgp 120; type-specific neutralizing antibody responses against the SF-2 strain of HIV-1 (HIV-1/SF-2) were induced in all 13. Nine of the 13 had crossreactive neutralizing activity against the MN strain of HIV-1 (HIV-1/MN), and 2 had crossreactive neutralizing activity against the IIIB strain of HIV-1 (HIV-1/IIIB). Twelve patients had typespecific fusion inhibition activity; only 1 had crossreactive fusion inhibition activity against HIV-1/MN. The monthly vaccination schedule used in part B resulted in decreased antibody titers, indicating that a rest period in the schedule is necessary for maximal immunogenicity. Lymphoproliferative responses against gp120 were induced in all vaccine recipients. The stimulation index to gp120 was persistently greater than 15 for 6 months after the last booster vaccination was given. CD8+ cytotoxic T-lymphocyte activity was detected in 1 of the 11 participants tested. Vaccine that contained MTP-PE caused a greater number of moderate or severe local and systemic reactions (of 16 participants, 4 had local reactions and 13 had systemic reactions) than did vaccine formulated with MF59 alone (of 16 participants, 7 had local reactions [P < 0.01] and 0 had systemic reactions [P < 0.001]).

CONCLUSIONS

The SF-2 rgp120 vaccine is safe and immunogenic. Three vaccinations with rgp120 in MF59 can induce type-specific and crossreactive neutralizing antibody against B-subtype laboratory strains of HIV-1. Human immunodeficiency virus-specific lymphoproliferative responses were induced in all vaccinated participants, and CD8+ cytotoxic T-lymphocyte activity was shown in one participant. A trend toward the augmentation of lymphoproliferative and humoral responses by MTP-PE was seen in the participants receiving 15 micrograms of rgp120. However, MTP-PE caused a statistically significant increase in the incidence of local and systemic side effects, which was felt to outweigh the small increase in immunogenicity provided by this biological response modifier in an otherwise well-tolerated vaccine.

Antibody to native human immunodeficiency virus type 1 envelope glycoproteins induced by IIIB and MN recombinant gp120 vaccines. The NIAID AIDS Vaccine Evaluation Group

The ability of antibody induced by MN and IIIB recombinant gp120 (rgp120) human immunodeficiency virus type 1 (HIV-1) vaccines the bind to oligomeric native and monomeric recombinant HIV-1 envelope glycoproteins (rgp 120) was measured in 25 uninfected, healthy adult volunteers. A major focus was to evaluate the effect of simultaneous and sequential immunization with vaccines representing different strains of HIV-1 on the ability to broaden cross-reactivity of antibodies against these and other HIV-1 strains. A flow cytometric indirect immunofluorescence assay (FIFA) to detect vaccine-induced antibody to envelope glycoprotein expressed by infected and rgp120-coated target cells was used, MN rgp120 HIV-1 vaccine given alone and coadministered with IIIB rgp120 HIV-1 vaccine elicited antibody which bound to cells infected with HIV-1MN, HIV-IIIB, HIV-1RF, and HIV-1-SF2. The presence of envelope glycoprotein-binding antibody detected by FIFA correlated to a moderate degree with functional antibody against HIV-1MN and HIV-IIIB. Priming immunization with IIIB rgp120 HIV-1 vaccine followed by booster injections of MN rgp120 HIV-1 vaccine resulted in increased cross-reactive antibody binding to these and heterologous clade B HIV-1 strains infecting cells. MN rgp120 HIV-1 vaccine given alone was better able to induce cross-reactive antibody to cells infected with heterologous HIV-1 laboratory strains than was IIIB rgp120 HIV-1 vaccine given alone. The vaccines induced binding antibody to rgp120 possessing the amino acid sequence of a clade E HIV-1 strain as measured by enzyme-linked immunosorbent assay. Levels of antibody binding to cells infected with clade B HIV-1 and cells coated with monomeric rgp120 were greater than that induced by HIV-1IIIB-based gp160 vaccines in previous studies.

Potent inhibition of HIV type 1 infection of mononuclear phagocytes by synthetic peptide analogs of HIV type 1 protease substrates

The HIV-1 genome encodes a protease that is required for viral processing of the precursor polyproteins Pr55gag and Pr160gag-pol. Interference with this process in human lymphocytes inhibits production of infectious virus. We tested the ability of several protease inhibitors to decrease replication of HIV-1BaL in human monocytes and peritoneal macrophages. The compounds tested are oligopeptide analogs of HIV-1 protease substrates in which the scissile dipeptide has been replaced by a hydroxyethylene isostere. The protease inhibitors were added only once, 1 hr prior to inoculation with virus. Every 3-5 days, half the medium was replaced with fresh medium. Inhibition of virus production was assessed by measuring reverse transcriptase (RT) activity in supernatant medium 14 days after infection. The concentration of drug required to inhibit infection by 50% (IC50) in monocytes ranged from 0.17 to 2.99 microM; IC50 values for peritoneal macrophages ranged from 0.21 to 1.9 microM. The IC50 values for these compounds were 1.1- to 10-fold higher when tested in monocytes compared to their inhibitory effect in lymphocytes, although still potently effective in the dosage range that appeared nontoxic to cells. Cell toxicity was seen only at concentrations greater than 10 microM, and varied among the drugs tested. Immunoblot analysis of two of the drugs (SB205700 and SB108922) confirmed inhibition of polyprotein processing. In control cells, 22% of viral protein pr55 was processed to p24 by 24 hr, and 51% was processed by 48 hr. In cells treated with the protease inhibitors (2 microM), Pr55 processing was inhibited 77% at 24 hr and 89% at 48 hr. Thus, these synthetic peptide analogs potently inhibit productive infection of mononuclear phagocytes by HIV-1. Drugs of this class may be useful for the treatment of HIV-1 infection in humans.