Probiotics and the prevention of necrotizing enterocolitis in preterm infants: A systematic review of the literature

Necrotizing enterocolitis is a common gastrointestinal disease associated with high mortality and morbidity among preterm infants. This was a systematic literature review that evaluated whether the administration of probiotic supplements is of benefit in the prevention of NEC. The search was narrowed to randomized clinical trials identified through The Cochrane Central Register of Controlled Trials, U.S. National Institute of Health clinical trials registry database, Pub Med and OVID MEDLINE databases. Inclusion criteria were: prospective, randomized clinical trials that administered probiotics as a preventive measure against NEC for infants of early gestational age (<35 wks) and/or low birth weight (<1500g), maintained NEC as the primary measured outcome, used Bell’s classification for NEC diagnosis with reports of stage 2 NEC or higher, and began probiotic administration within 10 days of life. Trials were excluded if participant enrollment was fewer than 100 infants, published before the year 2000, or probiotic supplementation was discontinued after less than seven consecutive days. Based on specific study characteristics, each resulting article was then judged by two authors for study quality. The search was further narrowed to studies of either high or moderate quality, which were then summarized in a set of tables based on study characteristics and results. From an initial set of 20 identified studies, five clinical trials met all criteria; each was discussed thoroughly based on trial limitations, strengths and comparisons to other included publications. Based on this review, the weight of evidence appears to support the use of probiotic supplementation in preterm infants as a preventive measure against NEC. Recommendations for future research were also provided.^

Factors affecting prenatal care use and pregnancy outcome in Texas: A comparative study among and within Black, Anglo, and Hispanic populations

This research project is a study in the field of public health to test the relationships of demographic, socioeconomic, behavioral, and biological factors with (1) prenatal care use and (2) pregnancy outcome, measured by birth weight. It has been postulated that demographic, socioeconomic, and behavioral factors are associated with differences in the use of prenatal care services. It has also been postulated that differences in demographic, socioeconomic, behavioral, and biological factors result in differences in birth weight. This research attempts to test these two basic conceptual frameworks. At the same time, an attempt is made to determine the population groups and subgroups that are at increased risk (1) of using fewer prenatal care visits, and (2) of displaying a higher incidence of low birth weight babies. An understanding of these relationships of the demographic, socioeconomic, behavioral, and biological factors in the use of prenatal care visits and pregnancy outcome, measured by birth weight, will potentially offer guidance in the planning and policy development of maternal and child health services. The research considers four major components of maternal characteristics: (1) Demographic factors. Ethnicity, household size, maternal parity, and maternal age; (2) Socioeconomic factors. Maternal education, family income, maternal employment, health insurance coverage, and household dwelling; (3) Behavioral factors. Maternal smoking, attendance at child development classes, mother's first prenatal care visit, total number of prenatal care visits, and adequacy of care; and, (4) Biological factors. Maternal weight gain during pregnancy.^ The research considers 16 independent variables and two dependent variables.^ It was concluded that: (1) Generally, differences in demographic, socioeconomic, and behavioral factors were associated with differences in the average number of prenatal care visits between and within population groups and subgroups. The Hispanic mothers were the lowest users of prenatal care services. (2) In some cases, differences in demographic, socioeconomic, behavioral, and biological factors demonstrated differences in the average birth weight of infants between and within population groups and subgroups. (3) Differences in demographic, socioeconomic, behavioral, and biological factors resulted in differences in the rates of low birth weight babies between and within population groups and subgroups. The Black mothers delivered the highest incidence of low birth weight infants.^ These findings could provide guidance in the formulation of public health policies such as MCH services, an increase in the use of prenatal care services by prospective mothers, resulting in reduction of the incidence of low birth weight babies, and consequently aid in reducing the rates of infant mortality. ^

The social construction of infant mortality: From grassroots to medicalization

Infant mortality as a problematic situation has been recognized for some 130 years in one form or another. It has undergone various changes in its empirical dimensions relative to whom we study within the population, what we study--low birth-weight vs. pre-term births--and how we study it--whether demographically or medically. An analysis of the process by which the condition was raised by claims makers as an intolerable situation among America's urban residents reveals that demographic and medical data were sparse. Nonetheless, a judgement about the meaning and significance of the condition was made, and that interpretation led to the promulgation of systems to both document and address the condition as it has come to be defined.^ This investigation depicts the historical context and natural history of infant mortality as one of a number of social problems that came to be defined through the interplay among groups and individuals making claims and how their claims came to the public policy agenda as worthy of collective resources--who won, who lost and why. The process of social definition focuses attention on the claims makers and the ways they contrast the meaning, origins and remedies for this troubling condition. The historical context becomes the frame of reference for understanding the actions of the claims makers and the meaning and significance they attached to the problem.^ We purport that "context" provides a closer reality than disjoined "value free" accounts. Context provides the evidence for the definition, who participated in the process, why and by what means.^ The role of women in the definitional process reveals the differences in approaches utilized by the women of the settlement house reform movement and African-American women working at the grass-roots. Much of the work done by these two groups provided options to the problem's remedy; however, their differences paved the way to our current (principally medically-oriented) definition and its inherent limitations. ^

INFANT MORTALITY IN THE MEXICAN AMERICAN COMMUNITY: AN ANALYSIS OF DIFFERENTIALS IN INFANT, NEONATAL, AND POSTNEONATAL MORTALITY BY ETHNICITY AND PARENTAL NATIVITY, 1974-75 SINGLE LIVE BIRTH COHORT, HARRIS COUNTY, TEXAS

The paradoxically low infant mortality rates for Mexican Americans in Texas have been attributed to inaccuracies in vital registration and idiosyncracies in Mexican migration in rural areas along the U.S.-Mexico border. This study examined infant (IMR), neonatal (NMR), and postneonatal (PNMR) mortality rates of Mexican Americans in an urban, non-border setting, using linked birth and death records of the 1974-75 single live birth cohort (N = 68,584) in Harris County, Texas, which includes the city of Houston and is reported to have nearly complete birth and death registration. The use of parental nativity with the traditional Spanish surname criterion made it possible to distinguish infants of Mexican-born immigrants from those of Blacks, Anglos, other Hispanics, and later-generation, more Anglicized Mexican Americans. Mortality rates were analyzed by ethnicity, parental nativity, and cause of death, with respect to birth weight, birth order, maternal age, legitimacy status, and time of first prenatal care.^ While overall IMRs showed Spanish surname rates slightly higher than Anglo rates, infants of Mexican-born immigrants had much lower NMRs than did Anglos, even for moderately low birth weight infants. However, among infants under 1500 grams, presumably unable to be discharged home in the neonatal period, Mexican Americans had the highest NMR. The inconsistency suggested unreported deaths for Mexican American low birth weight infants after hospital discharge. The PNMR of infants of Mexican immigrants was also lower than for Anglos, and the usual mortality differentials were reversed: high-risk categories of high birth order, high maternal age, and late/no prenatal care had the lowest PNMRs. Since these groups' characteristics are congruent with those of low-income migrants, the data suggested the possibility of migration losses. Cause of death analysis suggested that prematurity and birth injuries are greater problems than heretofore recognized among Mexican Americans, and that home births and "shoebox burials" may be unrecorded even in an urban setting.^ Caution is advised in the interpretation of infant mortality rates for a Spanish surname population of Mexican origin, even in an urban, non-border area with reportedly excellent birth and death registration. ^

Sudden Infant Death disparities: A systematic review on health education and policy recommendations for decreasing Sudden Infant Death in the African-American community

Objective: To perform a systematic review of the literature on SIDS and SUID deaths concentrated in the African-American community, describe health education and policy recommendations and recommend a new approach that may aid in decreasing the disparity of infant mortality in the African-American community. ^ Methods: The PubMed database was systematically searched to identify relevant articles for final review and analysis. Using the CASP 2006 system to critique literature, twelve articles were found that met inclusion and exclusion criteria. ^ Results: Evidence in the literature confirmed there was a current disparity among African Americans' infant mortality rates in comparison to other US ethnic groups. The underlying reasons for these disparities included the following maternal and infant characteristics: mothers younger than eighteen, having more than one live infant, having a high school education or less, never been married, and have infants born preterm or with low birth weight. Maternal smoking, substance abuse, and breastfeeding did not have a significant impact on infant sleep environments among African Americans. ^ Conclusion: Tailored health education programs at the community level, better access to pre-pregnancy and prenatal care, and increased maternal perception of risk that is relevant to the infants sleeping environment are all possible solutions that may decrease African American infant mortality rates.^

Black/white disparities in infant mortality rates in the U.S.: A quality of care perspective

The infant mortality rate for non-Hispanic Black infants in the U.S. is 13.63 deaths per 1,000 live births while the IMR for non-Hispanic White persons in the U.S. is 5.76 deaths per 1,000 live births. Black women are 2 times as likely as White women to deliver preterm infants and Black women are 2 times as likely as White women to deliver low birth weight infants (weighing less than 2,500 grams at birth). Differential underlying risk factors among mothers of different racial/ethnic groups for delivering pre-term and low birth weight infants have been historically accepted as the cause of racial disparities in IMRs. However, differential underlying risk status may not be the only major causative factor. Differential or unequal access to and provision of care is widely speculated to be a leading contributing factor to the wide racial disparity in infant mortality.2 This paper conducts a systematic review of existing literature investigating racial disparities in obstetrical care provided by healthcare practitioners to evaluate whether inequities in healthcare services provided to pregnant mothers and their neonates exist. The search terms "racial disparities obstetrical care," "racial differences quality of prenatal care," and "infant mortality racial disparities" were entered into the EBSCO Medline, Ovid Medline, PubMed, and Academic Search Complete databases, and articles between years 1990–2011 were selected for abstract review. The only articles included were those that used statistical methods to assess whether racial inequalities were present in the obstetrical services provided to pregnant women. My literature search returned 5 articles. Four of the five studies yielded significant racial differences in obstetrical care. However, the one study that used a large, nationally representative valid sample did not represent significant differences. Thus, this review provides initial evidence for racial disparities in obstetrical care, but concludes that more studies are needed in this area. Not all of the studies reviewed were consistent in the use and measurement of services, and not all studies were significant. The policy and public health implications of possible racial disparities in obstetrical care include the need to develop standard of care protocols for ALL obstetrical patients across the United States to minimize and/or eliminate the inequities and differences in obstetrical services provided.^

Cellular Uptake of Neutrohpil Elastase Links Inflammation to Adaptive Immunity

Many tumors arise from sites of inflammation providing evidence that innate immunity is a critical component in the development and progression of cancer. Neutrophils are primary mediators of the innate immune response. Upon activation, an important function of neutrophils is release of an assortment of proteins from their granules including the serine protease neutrophil elastase (NE). The effect of NE on cancer has been attributed primarily to its ability to degrade the extracellular matrix thereby promoting invasion and metastasis. Recently, it was shown that NE could be taken up by lung cancer cells leading to degradation of insulin receptor substrate-1 thereby promoting hyperactivity of the phosphatidylinositol-3 kinase (PI3K) pathway and tumor cell proliferation. To our knowledge, nobody has investigated uptake of NE by other tumor types. In addition, NE has broad substrate specificity suggesting that uptake of NE by tumor cells could impact processes regulating tumorigenensis other than activation of the PI3K pathway. Neutrophil elastase has been identified in breast cancer specimens where high levels of NE have prognostic significance. These studies have assessed NE levels in whole tumor lysates. Because the major source of NE is from activated neutrophils, we hypothesized that breast cancer cells do not have endogenous NE but may take up NE released by tumor associated neutrophils in the tumor microenvironment and that this could provide a link between the innate immune response to tumors and specific adaptive immune responses. In this thesis, we show that breast cancer cells lack endogenous NE expression and that they are able to take up NE resulting in increased generation of low molecular weight cyclin E (CCNE) and enhanced susceptibility to lysis by CCNE-specific cytotoxic T lymphocytes. We also show that after taking up NE and proteinase 3 (PR3), a second primary granule protease with significant homology to NE, breast cancer cells cross-present the NE- and PR3-derived peptide PR1 rendering them susceptible to PR1-targeted therapies. Taken together, our data support a role for NE uptake in modulating adaptive immune responses against breast cancer.

The association between parity and selected structural birth defects

BACKGROUND: Parity is a risk factor in neonatal morbidity and mortality. This dissertation examined the association between first births and selected birth defects. The first aim was to assess the risk of 66 birth defects among first births and third or greater births. The second aim was to determine if maternal race, maternal age, infant sex or infant birth weight modify the association between first births and selected birth defects. METHODS: The Texas Birth Defects Registry provided data for 1999-2009. For the first aim, odds ratios were calculated for each birth defect. For the second aim, analysis was restricted to the ten birth defects significantly associated with first births. Stratified analyses were conducted and interaction terms were added to logistic regression models to assess whether differences in the odds ratios for the effect of first birth were statistically significant across strata. RESULTS: Findings for the first aim showed that first births had significantly increased odds of having an infant with 24 of the 66 birth defects. Third or greater births had significantly increased odds of having four of the 66 birth defects. For the second aim, a number of significant effect modifiers were observed. For patent ductus arteriosis, obstructive urinary defects and gastroschisis, the effect of first births was significantly modified by black or U.S.-born Hispanic mothers. The effect of first birth was also significantly modified among mothers ≥30 years for mitral valve insufficiency, atrial septal defect and congenital hip dislocation. The effect of first births was significantly modified among infants with low birth weight for hypospadias, congenital hip dislocation and gastroschisis. CONCLUSIONS: First births were associated with an elevated risk of 24 categories of birth defects. For some of the birth defects studied, the effect of first birth is modified by maternal age, maternal race and low birth weight. Knowledge of the increased risk for birth defects among women having their first birth allows physicians and midwives to provide better patient care and spur further research into the etiology of associated birth defects. This knowledge may bring about interventions prior to conception in populations most likely to conceive.^

The effects of adequacy and content of prenatal care on birth outcomes in a high -risk Missouri population

The purpose of this observational study was investigation of the relationship between quantitative adequacy of prenatal care, specific prenatal care content and pregnancy outcome in a high risk Missouri population. A sample of 1484 women from three Missouri regions known to have high rates of low birth weight, infant mortality, and inadequate prenatal care rates participated in structured post-partum interviews. Approximately one-half of the sample had received adequate prenatal care and the other half inadequate prenatal care as determined by an index utilized by the Missouri Department of Health.^ Prenatal care content was assessed by reports of prenatal education in six different areas: Diet, smoking, alcohol, drug, preterm labor counseling, and advice on when to call the health provider if preterm labor was suspected by the woman. Low birth weight, in both term and preterm infants, were the two birth outcomes examined. A variety of maternal socio-demographic variables were also considered.^ The results of this study suggest that specific educational content, delivered during prenatal care, may have lessen the risk of giving birth to a preterm-low birth weight infant. Prenatal education for recognition of preterm labor, and advice on when to call the health provider if preterm labor was suspected were found to be associated with a decreased risk of preterm delivery. Specific educational content was not, however, associated with risk of term-low weight birth nor was quantitative adequacy of care associated with the risk of either term- or preterm-low birth weight.^ These findings reinforce a body of literature which stresses the importance of appropriate prenatal care in preventing preterm low birth weight. Additionally, the findings suggest interventions that may be specifically effective for prematurity prevention. ^

Proceedings of the 22nd Annual Biochemical Engineering Symposium

This is the twenty-second of a series of symposia devoted to talks and posters by students about their biochemical engineering research. The first, third, fifth, ninth, twelfth, sixteenth, and twenti~th were hosted by Kansas State University, the second and fourth by the University of Nebraska- Lincoln, the sixth, seventh, tenth, thirteenth, seventeenth, and twenty-second by Iowa State University, the eighth, fourteenth, and nineteenth by the University of Missouri-Columbia, the eleventh, fifteenth, and twenty-first by Colorado State University, and the eighteenth by the University of Colorado. Next year's symposium will be at the University of Oklahoma. Symposium proceedings are edited and issued by faculty of the host institution. Because final publication usually takes place in refereed journals, articles included here are brief and often cover work in progress. ContentsC. A. Baldwin, J.P. McDonald, and L. E. Erickson, Kansas State University. Effect of Hydrocarbon Phase on Kinetic and Transport Limitations for Bioremediation of Microporous Soil J. C. Wang, S. K. Banerji, and Rakesh Bajpai, University of Missouri-Columbia. Migration of PCP in Soil-Columns in Presence of a Second Organic Phase Cheng-Hsien Hsu and Roger G. Harrison, University of Oklahoma. Bacterial Leaching of Zinc and Copper from Mining Wastes James A. Searles, Paul Todd, and Dhinakar S. Kompala, University of Colorado. Suspension Culture of Chinese Hamster Ovary Cells Utilizing Inclined Sedimentation Ron Beyerinck and Eric H. Dunlop, Colorado State University. The Effect of Feed Zone Turbulence as Measured by Laser Doppler Velocimetry on Baker's Yeast Metabolism in a Chemostat Paul Li-Hong Yeh, GraceY. Sun, Gary A. Weisman, and Rakesh Bajpai, University of Missouri-Columbia. Effect of Medium Constituents upon Membrane Composition of Insect Cells R. Shane Gold, M. M. Meagher, R. Hutkins, and T. Conway, University of Nebraska-Lincoin. Ethanol Tolerance and Carbohydrate Metabolism in Lactobacilli John Sargantanis and M. N. Karim, Colorado State University. Application of Kalman Filter and Adaptive Control in Solid Substrate Fermentation D. Vrana, M. Meagher, and R. Hutkins, University of Nebraska-Lincoln. Product Recovery Optimization in the ABE Fermentation Kalyan R. Tadikonda and Robert H. Davis, University of Colorado. Cell Separations Using Targeted Monoclonal Antibodies Against Surface Proteins Meng H. Heng and Charles E. Glatz, Iowa State University. Charged Fusion for Selective Recovery of B-Galactosidase from Cell Extract Using Hollow Fiber Ion-Exchange Membrane Adsorption Hsiu-Mei Chen, Peter J. Reilly, and Clark Ford, Iowa State University. Site-Directed Mutagenesis to Enhance Thermostability of Glucoamylase from Aspergillus: A Rational Approach P. Tuitemwong, L. E. Erickson, and D. Y. C. Fung, Kansas State University. Applications of Enzymatic Hydrolysis and Fermentation on the Reduction of Flatulent Sugars in the Rapid Hydration Hydrothermal Cooked Soy Milk Sanjeev Redkar and Robert H. Davis, University of Colorado. Crossflow Microfiltration of Yeast Suspensions Linda Henk and James C. Linden, Colorado State University, and Irving C. Anderson, Iowa State University. Evaluation of Sorghum Ensilage as an Ethanol Feedstock Marc Lipovitch and James C. Linden, Colorado State University. Stability and Biomass Feedstock Pretreatability for Simultaneous Saccharification and Fermentation Ali Demirci, Anthony L. Pometto Ill, and Kenneth E. Johnson, Iowa State University. Application of Biofilm Reactors in Lactic Acid Fermentation Michael K. Dowd, Peter I. Reilly, and WalterS. Trahanovsky, Iowa State University. Low Molecular-Weight Organic Composition of Ethanol Stillage from Corn Craig E. Forney, Meng H. Heng, John R. Luther, Mark Q. Niederauer, and Charles E. Glatz, Iowa State University. Enhancement of Protein Separation Using Genetic Engineering J. F. Shimp, J. C. Tracy, E. Lee, L. C. Davis, and L. E. Erickson, Kansas State University. Modeling Contaminant Transport, Biodegradation and Uptake by Plants in the Rhizosphere Xiaoqing Yang, L. E. Erickson, and L. T. Fan, Kansas State University. Modeling of Dispersive-Convective Characteristics in Bioremediation of Contaminated Soil Jan Johansson and Rakesh Bajpai, University of Missouri-Columbia. Fouling of Membranes J. M. Wang, S. K. Banerji, and R. K. Bajpai, University of Missouri-Columbia. Migration of Sodium-Pentachorophenol (Na-PCP) in Unsaturated and Saturated Soil-Columns J. Sweeney and M. Meagher, University of Nebraska-Lincoln. The Purification of Alpha-D-Glucuronidase from Trichoderma reesei

Proceedings of the 24th Annual Biochemical Engineering Symposium

The 24th Biochemical Engineering Symposium was held 9-10 September 1994 at the YMCA of the Rockies conference center in Estes Park, Colorado, under the sponsorship of the Department of Chemical Engineering at the University of Colorado. Previous symposia in this series have been hosted by Kansas State University (1st, 3rd, 5th, 9th, 12th, 16th, 20th), University of Nebraska-Lincoln (2nd, 4th), Iowa State University (6th, 7th, 10th, 13th, 17th, 22nd), University of Missouri-Columbia (8th, 14th, 19th), Colorado State University (11th, 15th, 21st), University of Colorado (18th), and the University of Oklahoma (23rd). The next symposium is scheduled to be held at the University of Missouri-Columbia. The symposia are devoted to talks by students about their ongoing research. Because final publication usually takes place elsewhere, the papers included in the proceedings are brief, and often cover work in progress. ContentsIn-Well Aeration: An Innovative Subsurface Remediation TechnologyPrashant Gandhi, X. Yang, L.E. Erickson, and L. T. Fan; Kansas State University Expression of an Antimicrobial Peptide Analog in Eacherlchill coliChris Haught and Roger G. Harrison; University of Oklahoma Using High-frequency Backpulaing to Maximize Croasflow Filtration PerformanceSanjeev G. Redkar and Robert H. Davis; University of Colorado Low Molecular Weight Organic Compositions of Acid Waters from Vegetable Oil SoapstocksSteven L. Johansen, Arunthathi Sivasothy, Peter J. Reilly, and Earl G. Hammond; Iowa State University; Michael K. Dowd; U.S. Department of Agriculture Gas Phase Composition Effects on Suspension Cultures of Taxus cuspidata Noushin Mirjalili and James C. Linden; Colorado State University Cybernetic Modeling of Spontaneous Oscillations in Continuous Cultures of Ssccharomyces cerevisiaeKenneth D. Jones and Dhinakar S. Kompala; University of Colorado The Effect of Turbulent Shear on Calcium Mobilization in Mammalian CellsChristopher M. Cannizzaro, Pradyumna K. Namdev, and Eric H. Dunlop; Colorado State University Experimental Studies of Droplet Ejection at the Free Surface In Sparged ReactorsT. Y. Yiin, L A. Glasgow, and L. E. Erickson; Kansas State University The Role of Domain E (Starch-Binding Region) on the Activity of a Bacillus macersns Cyclodextrln GlucanotransferaseHai-yin Chang, Trang Le, and Zivko L. Nikolov; Iowa State University Use of the Rotating Wall Vessel for Study of Plant Cell Suspension CulturesXinzhi Sun and James C. Linden; Colorado State University A Novel Counter-Current Distribution Apparatus for the Study of Multi-Stage Aqueous Two-Phase Extraction of Biomolecules and Cell ParticlesMartin R. Guinn and Paul Todd; University of Colorado The Dynamics of Unhooking and Contraction of a Polyelectrolyte Chain Around an Isolated PostLin Zhang and Edith M. Sevick; University of Colorado A Laboratory Study of the Fate of Trichloroathylene and 1,1,1-Trlchloroathane In the Presence of Alfalfa PlantsMuralidharan Narayanan, Ryan M. Green, Lawrence C. Davis, and Larry E. Erickson; Kansas State University Modeling the Fate of Pyrene In the RhIzosphereS.K. Santharam, LE. Erickson, and L. T. Fan; Kansas State University Derivatization of MaltooligosaccharidesDaniela Prinz, Peter J. Reilly, and Zivko L. Nikolov; Iowa State University Probing Surfactant-Protein Binding by EPA SpectroscopyNarendra B. Bam, Yale University; Theodore W. Randolph; University of Colorado Optimization of a Stir-Cell Bioreactor for In Vitro Production of RNANeal T. Williams, Kim A. Wicklund, and Robert H. Davis; University of Colorado

Concentrations and carbon isotopic compositions of organic and inorganic compounds in sediment porewaters at IODP Site U1329

Ocean drilling has revealed the existence of vast microbial populations in the deep subseafloor, but to date little is known about their metabolic activities. To better understand the biogeochemical processes in the deep biosphere, we investigate the stable carbon isotope chemistry of acetate and other carbon-bearing metabolites in sediment pore-waters. Acetate is a key metabolite in the cycling of carbon in anoxic sediments. Its stable carbon isotopic composition provides information on the metabolic processes dominating acetate turnover in situ. This study reports our findings for a methane-rich site at the northern Cascadia Margin (NE Pacific) where Expedition 311 of the Integrated Ocean Drilling Program (IODP) sampled the upper 190 m of sediment. At Site U1329, d13C values of acetate span a wide range from -46.0 per mill to -11.0 per mill vs. VPDB and change systematically with sediment depth. In contrast, d13C values of both the bulk dissolved organic carbon (DOC) (-21.6 ± 1.3 per mill vs. VPDB) and the low-molecular-weight compound lactate (-20.9 ± 1.8 per mill vs. VPDB) show little variability. These species are interpreted to represent the carbon isotopic composition of fermentation products. Relative to DOC, acetate is up to 23.1 per mill depleted and up to 9.1 per mill enriched in 13C. Broadly, 13C-depletions of acetate relative to DOC indicate flux of carbon from acetogenesis into the acetate pool while 13C-enrichments of pore-water acetate relative to DOC suggest consumption of acetate by acetoclastic methanogenesis. Isotopic relationships between acetate and lactate or DOC provide new information on the carbon flow and the presence and activity of specific functional microbial communities in distinct biogeochemical horizons of the sediment. In particular, they suggest that acetogenic CO2-reduction can coexist with methanogenic CO2-reduction, a notion contrary to the hypothesis that hydrogen levels are controlled by the thermodynamically most favorable electron-accepting process. Further, the isotopic relationship suggests a relative increase in acetate flow to acetoclastic methanogenesis with depth although its contribution to total methanogenesis is probably small. Our study demonstrates how the stable carbon isotope biogeochemistry of acetate can be used to identify pathways of microbial carbon turnover in subsurface environments. Our observations also raise new questions regarding the factors controlling acetate turnover in marine sediments.

Score de riesgo para recién nacidos prematuros.

En países en vías de desarrollo como Argentina, la sobrevida de prematuros de peso inferior a 1000 gramos dista mucho de los resultados reportados por países desarrolladas. Controles prenatales deficitarios, recursos técnicos limitados y la saturación de los servicios de Neonatología son en parte responsables de estas diferencias. Una de las situaciones frecuentemente asociada a decisiones éticas en neonatología se produce en torno al prematuro extremo. Las preguntas más difíciles de responder son si existe un límite de peso o edad gestacional por debajo del cual no se deban iniciar o agregar terapéuticas encaminadas a salvar la vida, por considerarlas inútiles para el niño, prolongan sin esperanza la vida, hacen sufrir al paciente y su familia y ocupar una unidad que priva de atención a otro niño con mayores posibilidades de sobrevida. En el presente estudio se elaboró un score de riesgo neonatal constituido por variables que caracterizan a muchas poblaciones de nuestros países latinoamericanos y que fue validado estadísticamente.El score es de rápida y fácil realización. Permite predecir si el prematuro grave es recuperable o no, posibilitando tomar decisiones éticas basadas en una técnica validada, que permite actuar en el mayor beneficio del niño y su familia, al mismo tiempo que se hace un uso más equitativo de los recursos.

Concentration of C2-C6 hydrocarbon gases in dry sediments of ODP Sites 180-1109 and 180-1115

Low molecular weight hydrocarbon (LMWH) distributions were examined in sediments from Sites 1109 and 1115 in the western Woodlark Basin using purge-trap thermal adsorption/desorption gas analysis. A number of different hydrocarbon components >C1, which were not detected during shipboard gas analysis, were detected at both sites using the purge-trap procedure. Concentrations of ethane, propane, and butane remained relatively low (<100 pmol/g) throughout Site 1109 and had no consistent trend with depth. In contrast, the longer-chain components increased in concentration with depth. Hexane concentrations rose to 716 pmol/g at the base of the site with a concomitant increase in both 2-methyl- and 3-methylpentane. At Site 1115, concentrations of ethane, propane, butane, and isobutylene + 1-butene remained low (<60 pmol/g) throughout the site and again had no consistent trend with depth. 2-Methylpentane, 3-methylpentane, and hexane concentrations had a subsurface maximum that coincided with sediments containing abundant plant-rich material. The LMWH downhole profiles plus low in situ temperatures suggest that the LMWH components were formed in situ by low-temperature biological processes. Purge-trap analysis has indicated the presence of some unexpected deep low-temperature bacterial reactions, which demonstrates that further analysis of LMWH may provide valuable information at future Ocean Drilling Program sites.