Community Kangaroo Mother Care: implementation and potential for neonatal survival and health in very low-income settings.

OBJECTIVE: Immediate Kangaroo Mother Care (KMC), an intervention following childbirth whereby the newborn is placed skin-to-skin (STS) on mother's chest to promote thermal regulation, breastfeeding and maternal-newborn bonding, is being taught in very low-income countries to improve newborn health and survival. Existing data are reviewed to document the association between community-based KMC (CKMC) implementation and its potential benefits. STUDY DESIGN: New analyses of the sole randomized controlled study of CKMC in Bangladesh and others' experiences with immediate KMC are presented. RESULT: Newborns held STS less than 7 h per day in the first 2 days of life do not experience substantially better health or survival than babies without being held STS. CONCLUSION: Most women who were taught CKMC hold their newborns STS, but do so in a token manner unlikely to improve health or survival. Serious challenges exist to provide effective training and postpartum support to achieve adequate STS practices. These challenges must be overcome before scaling up.

Access to drinking-water and arsenicosis in Bangladesh.

The discovery of arsenic contamination in groundwater has challenged efforts to provide safe drinking-water to households in rural Bangladesh. Two nationally-representative surveys in 2000 and 2002 investigated water-usage patterns, water-testing, knowledge of arsenic poisoning, and behavioural responses to arsenic contamination. Knowledge of arsenicosis rose between the two surveys among women from 42% to 64% but awareness of consequences of arsenic remained limited; only 13% knew that it could lead to death. Behavioural responses to arsenic have been limited, probably in part because of the lack of concern but also because households are uncertain of how best to respond and have a strong preference for tubewell water even when wells are known to be contaminated. Further work conducted by the survey team highlighted the difficulties in providing alternative sources of water, with many households switching back to their original sources of water.

Searching for an optimum solution to the Bangladesh arsenic crisis.

Searching for an optimum solution to the Bangladesh arsenic crisis: Thirty years ago Bangladesh experienced very high levels of infant and child mortality, much of it due to water-borne disease in deltaic conditions where surface water was highly polluted. In what appeared to be one of the great public health achievements, 95% of the population were converted to drinking bacteria-free tubewell water from underground aquifers. Recently, it has been shown that perhaps 20% of this water is arsenic contaminated and alternatives to tubewell water have been sought. This paper reports on two national surveys collaboratively carried out in 2000 by the Health Transition Centre, Australian National University and Mitra and Associates, Dhaka: A census of tubewells and a household survey of tubewell use and arseniosis. The study found that the tubewell revolution has been promoted not only by health considerations but also by the demand for a household water facility and the desire by women to reduce workloads associated with using surface water. Because of this, and because the population had absorbed the message about safe tubewell water, it is argued that the movement away from the use of tubewell water should be as limited as possible, even if this means using safe tubewells which are often found in the neighbourhood. To enable such a move the most urgent need is not changing the source of water but comprehensive national water testing providing essential information to households about which wells are safe and which are not.

Causes of childhood deaths in Bangladesh: an update.

UNLABELLED: Knowledge of the causes of child death is important for health-sector planning since they relate to available interventions. Little is known about causes of child death in Bangladesh from the conventional sources since there is no vital registration system and very few deaths are attended by a qualified physician. To determine the cause structure of child deaths, verbal autopsy interviews were conducted in the Bangladesh Demographic and Health Survey (BDHS) 1993/94 national sample. Verbal autopsy is a method of finding out the causes of death based on an interview with the next of kin or other caregivers. Between BDHS 1993/94 and BDHS 1996/97, 1-4-y-old child mortality in Bangladesh declined by about 27.0%. This impressive decline prompted a verbal autopsy study using the BDHS 1996/97 national sample to determine whether the cause structure had changed. The same verbal autopsy instrument and methods to collect the data and the same computer algorithm to assign causes of death were used in both surveys. Comparison of BDHS 1993/94 and 1996/97 cause-specific mortality rates revealed that deaths due to almost all causes had declined, although significantly so only for acute respiratory infections (ARI), persistent diarrhoea and drowning. Deaths due to neonatal tetanus, acute watery diarrhoea and undernutrition had not decreased at all. CONCLUSION: Despite an impressive decline in deaths due to ARI, this condition remains the most important known cause of death in Bangladeshi children. Neonatal tetanus and measles together account for about 10% of deaths in children under 5 y. Further improvements in child survival are possible by improving access to and quality of available child survival interventions.

Eosinophil peroxidase catalyzes bromination of free nucleosides and double-stranded DNA.

Chronic parasitic infections are a major risk factor for cancer development in many underdeveloped countries. Oxidative damage of DNA may provide a mechanism linking these processes. Eosinophil recruitment is a hallmark of parasitic infections and many forms of cancer, and eosinophil peroxidase (EPO), a secreted hemoprotein, plays a central role in oxidant production by these cells. However, mechanisms through which EPO may facilitate DNA oxidation have not been fully characterized. Here, we show that EPO effectively uses plasma levels of bromide as a cosubstrate to brominate bases in nucleotides and double-stranded DNA, forming several stable novel brominated adducts. Products were characterized by HPLC with on-line UV spectroscopy and electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS). Ring assignments for brominated purine bases as their 8-bromo adducts were identified by NMR spectroscopy. Using stable isotope dilution LC/ESI/MS/MS, we show that while guanine is the preferred purine targeted for bromination as a free nucleobase, 8-bromoadenine is the major purine oxidation product generated following exposure of double-stranded DNA to either HOBr or the EPO/H(2)O(2)/Br(-) system. Bromination of nucleobases was inhibited by scavengers of hypohalous acids such as the thioether methionine, but not by a large molar excess of primary amines. Subsequently, N-monobromoamines were demonstrated to be effective brominating agents for both free nucleobases and adenine within intact DNA. A rationale for selective modification of adenine, but not guanine, in double-stranded DNA based upon stereochemical criteria is presented. Collectively, these results suggest that specific brominated DNA bases may serve as novel markers for monitoring oxidative damage of DNA and the nucleotide pool by brominating oxidants.

Role of eosinophil peroxidase in the origins of protein oxidation in asthma.

Eosinophils are uniquely endowed with an arsenal of enzymes that enable them to generate an array of reactive oxidants and diffusible radical species. The formidable arsenal at their disposal likely evolved because of the central role these phagocytes play in combating invading helminths and other large metazoan pathogens. Although these leukocytes constitute an essential component of the effector limb of host defenses, they also are implicated in contributing to inflammatory tissue injury. The growing prevalence and severity of asthma, a respiratory disease characterized by recruitment and activation of eosinophils in the airways of affected individuals, has focused research efforts on elaborating the many potential mechanisms through which eosinophils may contribute to tissue injury and oxidative modification of biological targets in asthma. Eosinophil activation is strongly suspected as playing a contributory role in the pathogenesis of asthma. Accordingly, an understanding of the basic chemical pathways available to the leukocytes for generating specific reactive oxidants and diffusible radical species in vivo is required. In the following review, recent progress in the elaboration of specific mechanisms through which eosinophils generate oxidants and other reactive species are discussed. The potential contributions of these intermediates to modification of biological targets during asthma are described. Particular emphasis is placed upon the secreted hemoprotein eosinophil peroxidase (EPO), a central participant in generation of reactive oxidants and diffusible radical species by the phagocytes.

Conversion of Vibrio eltor MAK757 to classical biotype: role of phage PS166.

Temperate phage PS166 infection of Vibrio eltor MAK757 resulted in complete changes in all biotype-specific determinants. About 10% of the PS166 lysogens of MAK757 lost their eltor-specific determinants, namely, the ability to produce soluble hemolysin, cell-associated hemagglutinin for chicken erythrocytes, and resistance to polymyxin B, as well as resistance to Mukherjee's group IV phage and sensitivity to eltor phage e4. These lysogens were found to have acquired the properties of classical strains, most significantly becoming sensitive to group IV phage but resistant to eltor-specific e4. The remainder of these lysogens, however, retained their parental biotype and serotype but acquired auxotrophy for glycine and histidine. The differential behavior of the two types of lysogen was due to the integration of the phage PS166 genome at different locations in the host chromosome. A 800-bp BglII fragment was found to contain the attP site. Phage PS166 has a polyhedral head (95 nm in diameter) and a contractile tail (98 nm in length). The phage chromosome is a linear double-stranded DNA of 110 kb and a G + C content of 58.7%.

The crystal structure of the octamer [r(guauaca)dC]2 with six Watson-Crick base-pairs and two 3' overhang residues.

The crystal structure of an alternating RNA octamer, r(guauaca)dC (RNA bases are in lower case while the only DNA base is in upper case), with two 3' overhang residues one of them a terminal deoxycytosine and the other a ribose adenine, has been determined at 2.2 A resolution. The refined structure has an Rwork 18.6% and Rfree 26.8%. There are two independent duplexes (molecules I and II) in the asymmetric unit cell, a = 24.95, b = 45.25 and c = 73.67 A, with space group P2(1)2(1)2(1). Instead of forming a blunt end duplex with two a+.c mispairs and six Watson-Crick base-pairs, the strands in the duplex slide towards the 3' direction forming a two-base overhang (radC) and a six Watson-Crick base-paired duplex. The duplexes are bent (molecule I, 20 degrees; molecule II, 25 degrees) and stack head-to-head to form a right-handed superhelix. The overhang residues are looped out and the penultimate adenines of the two residues at the top end (A15) are anti and at the bottom (A7) end are syn. The syn adenine bases form minor groove A*(G.C) base triples with C8-H...N2 hydrogen bonds. The anti adenine in molecule II also forms a triple and a different C2-H...N3 hydrogen bond, while the other anti adenine in molecule I does not, it stacks on the looped out overhang base dC. The 3' terminal deoxycytosines form two stacked hemiprotonated trans d(C.C)+ base-pairs and the pseudo dyad related molecules form four consecutive deoxyribose and ribose zipper hydrogen bonds in the minor groove.

Crystal Structure of an RNA Duplex [r(gugcaca)dC](2) with 3'-Dinucleoside Overhangs Forming a Superhelix.

Abstract Crystal structure of the RNA octamer duplex, [r(gugcaca)dC] (2), with space group I2(1)2(1)2(1) and the cell constants a=24.29, b=45.25 and c=73.68Å, has been determined and refined. The structural and packing architecture of the molecule consist of a highly bent six base paired duplex forming a right-handed superhelix stacked in tandem compared to an infinite pseudo- continuous column as is usually present in RNA crystal structures. The super helix could be formed by the head-to-head stacking (g1 over g1 and g9 over g9), the large bend and the twists at the junctions may also be responsible. The sugar-phosphate backbones of the 3'-end dinucleoside overhangs snuggly fit into the minor grooves of adjacent double helical stacks. The 3'-terminal deoxycytidines form antiparallel hemiprotonated trans (C·C)(+) pairs with symmetry related deoxycytidines, while the penultimate adenines form base triples (a*g·c) with the capping g·c base pairs of the hexamer duplex with the adenine (a7) at one end being syn and at the other anti. These triple interactions are the same as those found in the tetrahymena ribozyme and group I intron.

Formation of nitric oxide-derived oxidants by myeloperoxidase in monocytes: pathways for monocyte-mediated protein nitration and lipid peroxidation In vivo.

Protein nitration and lipid peroxidation are implicated in the pathogenesis of atherosclerosis; however, neither the cellular mediators nor the reaction pathways for these events in vivo are established. In the present study, we examined the chemical pathways available to monocytes for generating reactive nitrogen species and explored their potential contribution to the protein nitration and lipid peroxidation of biological targets. Isolated human monocytes activated in media containing physiologically relevant levels of nitrite (NO(2)(-)), a major end product of nitric oxide ((*)NO) metabolism, nitrate apolipoprotein B-100 tyrosine residues and initiate LDL lipid peroxidation. LDL nitration (assessed by gas chromatography-mass spectrometry quantification of nitrotyrosine) and lipid peroxidation (assessed by high-performance liquid chromatography with online tandem mass spectrometric quantification of distinct products) required cell activation and NO(2)(-); occurred in the presence of metal chelators, superoxide dismutase (SOD), and scavengers of hypohalous acids; and was blocked by myeloperoxidase (MPO) inhibitors and catalase. Monocytes activated in the presence of the exogenous (*)NO generator PAPA NONOate (Z-[N-(3-aminopropyl)-N-(n-propyl)amino]diazen-1-ium-1,2- diolate) promoted LDL protein nitration and lipid peroxidation by a combination of pathways. At low rates of (*)NO flux, both protein nitration and lipid peroxidation were inhibited by catalase and peroxidase inhibitors but not SOD, suggesting a role for MPO. As rates of (*)NO flux increased, both nitrotyrosine formation and 9-hydroxy-10,12-octadecadienoate/9-hydroperoxy-10,12-octadecadieno ic acid production by monocytes became insensitive to the presence of catalase or peroxidase inhibitors, but they were increasingly inhibited by SOD and methionine, suggesting a role for peroxynitrite. Collectively, these results demonstrate that monocytes use distinct mechanisms for generating (*)NO-derived oxidants, and they identify MPO as a source of nitrating intermediates in monocytes.

Structure of the side-by-side binding of distamycin to d(GTATATAC)2.

The 2.40 A resolution crystal structure of a side-by-side binding of distamycin A molecules to a DNA octamer d(GTATATAC)2 with an extended alternating TA sequence has been determined. The unit-cell parameters are a = 29.55, b = 42.18, c = 43.38 A, beta = 96.56 degrees, space group P21, with two molecules in the asymmetric unit, in contrast to all previous side-by-side distamycin-DNA complexes which have only a single DNA strand and one drug molecule in the asymmetric unit. The structure was solved by the molecular-replacement method and refined to an R index of 21.0% using 3467 reflections [>/= 2sigma(F)]. The minor grooves of the DNA molecules bind two side-by-side antiparallel staggered distamycins spanning about five base pairs and virtually covering the entire length of the DNA. The octamer duplexes exhibit low-high alternations in the helical twist, sugar puckering and the C-O3' and O3'-P torsion angles, similar to the earlier side-by-side complexes containing inosine bases. The molecules are stacked one over the other along the ac diagonal in an infinite pseudo-continuous helical column with no lateral interactions.

Crystal structure of an RNA 16-mer duplex R(GCAGAGUUAAAUCUGC)2 with nonadjacent G(syn).A+(anti) mispairs.

G.A mispairs are one of the most common noncanonical structural motifs of RNA. The 1.9 A resolution crystal structure of the RNA 16-mer r(GCAGAGUUAAAUCUGC)2 has been determined with two isolated or nonadjacent G.A mispairs. The molecule crystallizes with one duplex in the asymmetric unit in space group R3 and unit cell dimensions a = b = c = 49.24 A and alpha = beta = gamma = 51.2 degrees. It is the longest known oligonucleotide duplex at this resolution and isomorphous to the 16-mer duplex with the C.A+ mispairs [Pan, et al., (1998) J. Mol. Biol. 283, 977-984]. The C.A+ mispair behaves like a wobble pair while the G.A+ does not. The G.A mispairs are protonated at N1 of the adenines as in the C.A+ mispairs, and two hydrogen bonds in the G(syn).A+(anti) conformation are formed. The syn guanine is stabilized by an intranucleotide hydrogen bond between the 2-amino and the 5'-phosphate groups. The G(syn).A+(anti) conformation can provide a different surface for recognition in the grooves compared to other G.A hydrogen bonding schemes. The major groove is widened between the two mispairs allowing access to ligands. One of the 3-fold axes is occupied by a sodium ion and a water molecule, while a second is occupied by another water molecule.

Evaluation of the effect of a breastfeeding message integrated into a larger communication project.

Most breastfeeding project evaluations examine the effects of separate projects and many do not use experimental designs. We evaluated the impact during the 3rd year (March 1992-March 1993) of a simple breastfeeding message integrated into a large-scale 3 year vitamin A project in northern Bangladesh. It encouraged mothers to breastfeed for at least 2 years. Less formally, mothers were also advised to give colostrum. In both project (experimental) and non-project (control) areas, the proportion of mothers of children aged 1-6 years who said they gave colostrum increased from about 69 per cent to about 77 per cent. However, children born during the year that transpired between the pre- and post-surveys were too young to be included in the post-survey. Thus this difference is an example of women reporting what they perceived as the norm or the 'correct' answer instead of what they actually did with their children. Thus the norm changed during the evaluation year, but it did so equally in both project and non-project areas. Although reported breastfeeding levels remained stable among older groups, the proportion of children in the 2nd and 3rd years of life reported to be currently breastfeeding increased to a similar extent in both areas. This could indicate either a change in perception or a change in behaviour. Suckling frequency, not mentioned in local or national breastfeeding promotion, was unchanged in both areas at about 15 times a day for children in the 2nd year of life, and maintained at about eight to 10 times a day even for the small proportion who were still breastfed in the 5th (about 9 per cent) or 6th (about 2 per cent) years of life. While project messages (especially by radio) could have spread to the nearby non-project area, it is unlikely that the impact would be equal. More likely these changes were the result of secular changes occurring at this time throughout Bangladesh. Thus this evaluation found no evidence that the integration of a simple message about breastfeeding into a larger project had any measurable effect in the project area compared to the non-project area. More effective approaches may be required, tailored to the particular needs of women in the area.

Crystal structure of an RNA octamer duplex r(CCCIUGGG)2 incorporating tandem I.U wobbles.

The crystal structure of the RNA octamer duplex r(CCCIUGGG)2has been elucidated at 2.5 A resolution. The crystals belong to the space group P21and have unit cell constants a = 33.44 A, b = 43.41 A, c = 49.39 A and beta = 104.7 degrees with three independent duplexes (duplexes 1-3) in the asymmetric unit. The structure was solved by the molecular replacement method and refined to an Rwork/Rfree of 0.185/0.243 using 3765 reflections between 8.0 and 2.5 A. This is the first report of an RNA crystal structure incorporating I.U wobbles and three molecules in the asymmetric unit. Duplex 1 displays a kink of 24 degrees between the mismatch sites, while duplexes 2 and 3 have two kinks each of 19 degrees and 27 degrees, and 24 degrees and 29 degrees, respectively, on either side of the tandem mismatches. At the I.U/U.I mismatch steps, duplex 1 has a twist angle of 33.9 degrees, close to the average for all base pair steps, but duplexes 2 and 3 are underwound, with twist angles of 24.4 degrees and 26.5 degrees, respectively. The tandem I.U wobbles show intrastrand purine-pyrimidine stacking but exhibit interstrand purine-purine stacking with the flanking C.G pairs. The three independent duplexes are stacked non-coaxially in a head-to-tail fashion to form infinite pseudo-continuous helical columns which form intercolumn hydrogen bonding interactions through the 2'-hydroxyl groups where the minor grooves come together.

Structure of a 16-mer RNA duplex r(GCAGACUUAAAUCUGC)2 with wobble C.A+ mismatches.

The crystal structure of a 16-mer, the longest known RNA duplex, has been determined at 2.5 A resolution. The hexadecamer r(GCAGACUUAAAUCUGC) contains isolated C.A/A.C mismatches with two hydrogen bonds. The two hydrogen bonds in the mismatches suggests that N1 of A is protonated even though the crystallization was done at neutral pH. Therefore, the C.A mismatch is a C.A+ wobble similar to the G.U wobble. The two C.A+ pairs are isolated by four Watson-Crick pairs and flanked by five Watson-Crick base-pairs on either sides. Kinks/bends of 20 degrees are observed at the wobble sites. The Watson-Crick base-pair A5.U26 on the 5'-side of the first C6.A27(+) wobble has a twist angle of 27 degrees compared to the 3'-side U7.A28 pair of 36 degrees. The twist angles are reversed (37 degrees and 26 degrees) in the second A11(+).C22 wobble because of the approximate dyad in the molecule, the flanking base-pair sequences are A.U pairs. The wobbles expand the major groove to 7.1 A/7.3 A. The duplexes form helical columns and are tightly packed around the 31-screw axis. The minor grooves of adjacent columns in juxtaposition interact through the O2' atoms and the anionic phosphate oxygen atoms.

A novel end-to-end binding of two netropsins to the DNA decamers d(CCCCCIIIII)2, d(CCCBr5CCIIIII)2and d(CBr5CCCCIIIII)2.

Netropsin is bound to the DNA decamer d(CCCCCIIIII)2, the C-4 bromo derivative d(CCCBr5CCIIIII)2and the C-2 bromo derivative d(CBr5CCCCIIIII)2in a novel 2:1 mode. Complexes of the native decamer and the C-4 bromo derivative are isomorphous, space group P1, unit cell dimensions a = 32.56 A (32.66), b = 32.59 A (32.77), c = 37.64 A (37.71), alpha = 86.30 degrees (86.01 degrees), beta = 84.50 degrees (84.37 degrees), gamma = 68.58 degrees (68.90 degrees) with two independent molecules (A and B) in the asymmetric unit (values in parentheses are for the derivative). The C-2 bromo derivative is hexagonal P61, unit cell dimensions a = b = 32.13 A, c = 143.92, gamma = 120 degrees with one molecule in the asymmetric unit. The structures were solved by the molecular replacement method. The novelty of the structures is that there are two netropsins bound end-to-end in the minor groove of each B-DNA decamer which has nearly a complete turn. The netropsins are held by hydrogen bonding interactions to the base atoms and by sandwiching van der Waal's interactions from the sugar-phosphate backbones of the double helix similar to every other drug.DNA complex. Each netropsin molecule spans approximately 5 bp. The netropsins refined with their guanidinium heads facing each other at the center, although an orientational disorder for the netropsins cannot be excluded. The amidinium ends stretch out toward the junctions and bind to the adjacent duplexes in the columns of stacked symmetry-related complexes. Both cationic ends of netropsin are bridged by water molecules in one of the independent molecules (molecule A) of the triclinic structures and also the hexagonal structure to form pseudo-continuous drug.decamer helices.

1.76 A structure of a pyrimidine start alternating A-RNA hexamer r(CGUAC)dG.

The crystal structure of the alternating RNA r(CGUAC)dG with a 3'-terminal deoxy G residue has been determined at 1.76 A resolution. The crystal belongs to the orthorhombic space group C2221, unit-cell dimensions a = 29.53, b = 44.61 and c = 94.18 A, with two independent duplexes (I and II) per asymmetric unit. The structure was solved by the molecular-replacement method. The final R factor was 18.8% using 4757 reflections in the resolution range 8.0-1.76 A. The model contains a total of 496 atoms and 85 solvent molecules. The two duplexes form the repeating unit and stack in the usual head-to-tail (5',3'/5',3') fashion into a pseudocontinuous helical column. Almost all of the 2'-hydroxyl groups are engaged in the three modes of water-mediated interactions to the base N3/O2 atoms, the sugar O4' atoms and the backbone phosphates. Thus, the 2'-hydroxyl group of RNA is probably contributing to the stability of the duplexes.

Causes of childhood deaths in Bangladesh: results of a nationwide verbal autopsy study.

While knowledge of causes of deaths is important for health sector planning, little is known from conventional sources about the causes of deaths in Bangladesh. This is partly due to deficiencies in the registration system and partly because few deaths are attended by qualified physicians. The present study was undertaken to update the information available on causes of deaths among under-5-year-olds, taking advantage of advances in verbal autopsy methodology and of the national Bangladesh Demographic and Health Survey conducted in 1993-94. About 25% of the deaths were associated with acute lower respiratory infections (ALRI) and about 20% with diarrhoea. Neonatal tetanus and measles remained important causes of death, and drowning was a major cause for 1-4-year-olds. Research and programmes to enable mothers to identify ALRI cases, particularly pneumonia, and to encourage timely and appropriate care-seeking and strengthening of ALRI case management at the primary care facilities are important priorities. While promotion of oral rehydration for watery diarrhoea and antibiotic treatment for dysentery should continue, broader preventive interventions including provision of safe water and sanitation, and improvements in personal hygiene require more attention. Further intensification of immunization programmes and innovative experimental interventions to reduce childhood from drowning should be designed and tested.

PIP: Advances in verbal autopsy methodology and the availability of the 1993-94 Bangladesh Demographic and Health Survey data enabled an analysis of causes of childhood deaths in Bangladesh. Few deaths in Bangladesh are attended by qualified physicians and the registration system is deficient, making mortality analyses difficult with conventional sources. A follow-up survey of the 828 deaths of children under 5 years occurring in the 5 years preceding the 1993-94 survey was conducted in 1995. 311 deaths involved neonates, 232 occurred in the 1-11 month age group, and 285 were among children 12-59 months of age. 24.2% of deaths (40% of the infant deaths) were associated with acute lower respiratory infection (ALRI), 19.0% with diarrhea, 8.8% were due to accidents, and 5.4% were related to neonatal tetanus. Drowning accounted for 18.9% of deaths among 1-4 year olds. Malnutrition was associated with a third of the respiratory infections and half the diarrhea deaths. Urban deaths represented less than 10% of the total, but maternal educational status was not associated with different patterns of child mortality. Girls were less likely than boys to die from ALRI and more likely to die from malnutrition, measles, and diarrhea. Early recognition of pneumonia cases and appropriate care-seeking by parents, use of properly prepared oral rehydration solution in diarrhea, and measures to improve the general nutritional status of children would help improve child survival. Verbal autopsy instruments could be made more accurate if adapted based on mothers' recognition of signs and symptoms and the terms they use to describe them.

Design of specific structures using alpha,beta-dehydro-phenylalanine residues: synthesis, crystal structure, and molecular conformation of Boc-L-Val-delta Phe-delta Phe-L-Val-delta Phe-delta Phe-L-Val-OCH3, a 3(10)-helical heptapeptide.

The peptide design using alpha,beta-dehydro-residues has wide applications. To design an extensive 3(10)-helical conformation, a heptapeptide Boc-L-Val-delta Phe-delta Phe-L-Val-delta Phe-delta Phe-L-Val-OCH3, with a repeat of two consecutive delta Phe residues has been synthesized using an azlactone method in solution phase. This is the first design using a repeat of two consecutive delta Phe residues. It is observed that the delta Phe in a sequence of two consecutive delta Phe residues, adopts only one set of phi, psi values, i.e., +/- 60 degrees, +/- 30 degrees, thus making it a specific design tool. The peptide crystallized from its solution in a methanol-water mixture in the space group P2(1) with a = 10.159(5)A, b = 20.057(2)A, c = 14.448(3)A, beta = 99.41(2)degrees, V = 2904(2)A3. The structure has been determined by direct methods and refined to an R value of 0.048 for 5404 observed [I > or = 3 sigma(I)] reflections. The structure consists of a heptapeptide Boc-L-Val-delta Phe-delta Phe-L-Val-delta Phe-delta Phe-L-Val-OCH3 and a solvent methanol molecule in the asymmetric unit. All peptide units in the structure are trans. As a result of six overlapping type III beta-turns formed involving seven residues and five intramolecular 4-->1 hydrogen bonds, the peptide adopts a right-handed 3(10)-helical conformation with more than two complete helical turns. It is noteworthy that starting from the Boc group to the C-terminal residue of Val, the 3(10)-helical structure is maintained well. The carbonyl oxygen atom of the Boc group is the first acceptor whereas the carbonyl oxygen atom of Val4 is the last acceptor in the helical structure of the peptide. The side chains of four delta Phe residues in this helical arrangement exist in a slightly staggered arrangement. The solvent methanol molecule interacts through its hydroxyl group and forms two intermolecular hydrogen bonds, one as a donor with a C-terminal CO group of delta Phe6 and second as an acceptor with the NH group of delta Phe2 from the N-terminal region of the peptide. Thus the solvent molecule plays a significant role in promoting a head-to-tail packing of 3(10)-helices of the peptide. There are no lateral hydrogen bonds between the helices, but there exist several van der Waals interactions involving the hydrophobic side chains of peptide molecules.

Design of peptides using alpha,beta-dehydro-residues: synthesis, crystal structure and molecular conformation of Boc-L-Val-delta Phe-delta Phe-L-Val-OCH3.

The peptide Boc-L-Val-delta Phe-delta Phe-L-Val-OCH3 was synthesized by the azlactone method in solution phase, and its crystal and molecular structures were determined by x-ray diffraction method. Single crystals were grown by slow evaporation from a methanol/water solution at 6 degrees C. The crystals belong to an orthorhombic space group P212121 with a = 10.478 (6) A, b = 13.953 (I), c = 24.347 (2) and Z = 4. The structure was determined by direct methods and refined by least squares procedure to an R value of 0.052. The structure consists of a peptide and a water molecule. The peptide adopts two overlapping beta-turn conformations of Types II and I' with torsion angles: phi 1 = -54.8 (6) psi 1 = 130.5 (4), phi 2 = 65.8 (5), psi 2 = 12.8 (6), phi 3 = 79.4 (5), psi 3 = 3.9 (7) degrees. The conformation is stabilized by intramolecular hydrogen bonds involving Boc CO and NH of delta Phe3 and CO of Val1 and NH of Val4. The molecules are tightly packed in the unit cell. The crystal structure is stabilized by hydrogen bonds involving NH of delta Phe2 and CO of a symmetry related (x-1/2, 1/2-y, -z) delta Phe2. The solvent-water molecule forms two hydrogen bonds with peptide molecule involving NH of Val1 as an acceptor and another with CO of a symmetry related (1-x, y-1/2, 1/2 -z) delta Phe3 as a donor. These studies indicate that a tetrapeptide with two consecutive delta Phe residues sequenced with valines on both ends adopts two overlapping beta-turns of Types II and I'.