The Pregnancy, Arsenic, and Immune Response (PAIR) Study in rural northern Bangladesh

BACKGROUND

Arsenic exposure and micronutrient deficiencies may alter immune reactivity to influenza vaccination in pregnant women, transplacental transfer of maternal antibodies to the foetus, and maternal and infant acute morbidity.

OBJECTIVES

The Pregnancy, Arsenic, and Immune Response (PAIR) Study was designed to assess whether arsenic exposure and micronutrient deficiencies alter maternal and newborn immunity and acute morbidity following maternal seasonal influenza vaccination during pregnancy.

POPULATION

The PAIR Study recruited pregnant women across a large rural study area in Gaibandha District, northern Bangladesh, 2018-2019.

DESIGN

Prospective, longitudinal pregnancy and birth cohort.

METHODS

We conducted home visits to enrol pregnant women in the late first or early second trimester (11-17 weeks of gestational age). Women received a quadrivalent seasonal inactivated influenza vaccine at enrolment. Follow-up included up to 13 visits between enrolment and 3 months postpartum. Arsenic was measured in drinking water and maternal urine. Micronutrient deficiencies were assessed using plasma biomarkers. Vaccine-specific antibody titres were measured in maternal and infant serum. Weekly telephone surveillance ascertained acute morbidity symptoms in women and infants.

PRELIMINARY RESULTS

We enrolled 784 pregnant women between October 2018 and March 2019. Of 784 women who enrolled, 736 (93.9%) delivered live births and 551 (70.3%) completed follow-up visits to 3 months postpartum. Arsenic was detected (≥0.02 μg/L) in 99.7% of water specimens collected from participants at enrolment. The medians (interquartile ranges) of water and urinary arsenic at enrolment were 5.1 (0.5, 25.1) μg/L and 33.1 (19.6, 56.5) μg/L, respectively. Water and urinary arsenic were strongly correlated (Spearman's ⍴ = 0.72) among women with water arsenic ≥ median but weakly correlated (⍴ = 0.17) among women with water arsenic < median.

CONCLUSIONS

The PAIR Study is well positioned to examine the effects of low-moderate arsenic exposure and micronutrient deficiencies on immune outcomes in women and infants.

REGISTRATION

NCT03930017.

Post-Partum Spontaneous Coronary Artery Dissection with Occluded Left Anterior Descending Artery

Presentation We present a case of spontaneous coronary artery dissection (SCAD) in a 35-year-old lady who was 4 months post-partum. Despite a lack of typical risk factors, initial presentation and investigations were strongly suggestive of ACS. Diagnosis Coronary angiography revealed an occluded proximal left anterior descending (LAD) artery with TIMI 0 flow. Angiographic appearances and intravascular ultrasound (IVUS) were consistent with SCAD. Treatment A single drug-eluting stent was deployed, successfully restoring good flow, without extending the dissection flap. Discussion SCAD should be considered as an important and underdiagnosed cause of ACS, predominantly in young women without other apparent risk factors.

Impact of Protein Supplementation and Presumptive Treatment for Enteric Pathogens on Infant Growth from 6–12 Months of Age: Results of a Cluster-Randomized Controlled Trial

Objectives

Intake of high-quality protein may be insufficient to support growth in the context of high enteric pathogen carriage and environmental enteric dysfunction. Our objective was to test whether supplemental protein, with or without presumptive treatment for enteric pathogens, would improve infant growth from 6–12 months of age.

Methods

We conducted a 2 × 4 factorial cluster-randomized trial in rural Bangladesh. The first factor was azithromycin treatment (10 mg/kg * 3 days) or placebo at 6 & 9 months of age. The second factor, delivered from 6–12 months of age, consisted of: supplemental protein as daily porridge (125 kcal/d, with 10 g protein/day as egg white powder) or a daily egg; an isocaloric daily porridge; or nutrition education alone. The present aim tested the impact of the protein-rich porridge, with or without azithromycin treatment. All infants born in the study area over a 9-mo period were eligible and consented at ∼3 mo of age. Trained field workers measured infant size at 6, 9, and 12 mo of age using standardized protocols. We used linear regression with generalized estimating equations to test the interventions’ impact on anthropometric indices, respectively, at 12 mo of age, controlling for baseline measures. Analysis was intention-to-treat.

Results

Overall, 2205 infants were enrolled from 282 clusters and exposed to both nutrition (1074 in protein arm from 140 clusters; 1074 in the isocaloric arm from 142 clusters) and presumptive treatment interventions. At baseline, 18.7%, 16.9%, and 6.4% of infants were stunted, underweight, and wasted, respectively. There was no statistical interaction between protein supplementation and azithromycin treatment for any of the anthropometric indices, so groups were combined. In the analysis of main effects, added protein had no impact on mean length-for-age (β = 0.01; 95% CI: −0.06, 0.08), weight-for-age (β = −0.002; 95% CI: −0.06, 0.05), or weight-for-length (β = −0.04; 95% CI: −0.12, 0.05) Z-scores at 12 mo of age.

Conclusions

Supplemental protein from 6–12 mo of age had no effect on mean linear or ponderal growth measured at 12 mo of age, irrespective of presumptive treatment for enteric pathogens with azithromycin.

Funding Sources

The Bill and Melinda Gates Foundation.

The Effect of Eggs on Growth Among Infants 6–12 months of Age in Rural Bangladesh: A Cluster Randomized Controlled Trial

Objectives

To assess the impact of daily egg supplementation on infant growth from 6–12 months of age in Bangladesh.

Methods

A cluster randomized controlled trial was conducted in rural Bangladesh to test the effect of daily egg supplementation and nutrition education versus nutrition education alone on linear growth and stunting prevalence among infants. Infants were enrolled at 3 months of age and assigned to a trial arm based on their geographic sector of residence. Households were visited weekly to distribute eggs and monitor compliance starting at 6 months of age. Length, weight, head circumference, and mid upper arm circumference were measured at 6, 9, and 12 months, as well as dietary intake from home foods in the last 24 hours. Analyses were conducted on an intention-to-treat basis. Linear regression models were developed for continuous outcomes. For dichotomous outcomes, prevalence ratios were estimated using log-binomial regression models. Generalized estimating equations were used with all models to account for clustering. Each model was adjusted for the baseline measure of the outcome variable.

Results

Overall, 909 infants were enrolled in the treatment arm from 142 clusters and 842 infants in the control arm from 140 clusters. Prevalence of stunting at baseline was 19.4%, wasting was 6.7%, and underweight was 18.1%. After 6 months of supplementation, the intervention had no effect on mean length-for-age z-scores (β = 0.05, 95% CI: −0.12, 0.23) or prevalence of stunting (PR = 1.00, 95% CI: 0.90, 1.10). Infants in the egg arm had significantly higher mean weight-for-length z-scores (β = 0.11, 95% CI: 0.04, 0.18) and weight-for-age z-scores (β = 0.08, 95% CI: 0.03, 0.12), adjusting for baseline measures of the outcomes. Our presented results will include findings from mixed-effects regression analyses assessing the effect of the intervention on growth rate.

Conclusions

The provision of a daily egg for 6 months to infants in rural Bangladesh had an effect on ponderal but not linear growth.

Funding Sources

Bill and Melinda Gates Foundation.

Assessing Child Nutrient Intakes Using a Tablet-Based 24-Hour Recall Tool in Rural Zambia

BACKGROUND

Detailed dietary intake data in low-income populations are needed for research and program evaluation. However, collection of such data by paper-based 24-hour recall imposes substantial demands for staff time and expertise, training, materials, and data entry.

OBJECTIVE

To describe our development and use of a tablet-based 24-hour recall tool for conducting dietary intake surveys in remote settings.

METHODS

We designed a 24-hour recall tool using Open Data Kit software on an Android tablet platform. The tool contains a list of local foods, questions on portion size, cooking method, ingredients, and food source and prompts to guide interviewers. We used this tool to interview caregivers on dietary intakes of children participating in an efficacy trial of provitamin A-biofortified maize conducted in Mkushi, a rural district in central Zambia. Participants were children aged 4 to 8 years not yet enrolled in school (n = 938). Dietary intake data were converted to nutrient intakes using local food composition and recipe tables.

RESULTS

We developed a tablet-based 24-hour recall tool and used it to collect dietary data among 928 children. The majority of foods consumed were maize, leafy vegetable, or small fish dishes. Median daily energy intake was 6416 kJ (1469 kcal).

CONCLUSIONS

Food and nutrient intakes assessed using the tablet-based tool were consistent with those reported in prior research. The tool was easily used by interviewers without prior nutrition training or computing experience. Challenges remain to improve programming, but the tool is an innovation that enables efficient collection of 24-hour recall data in remote settings.

Behavioral effects and drug vulnerability in rats exposed to Pfiesteria toxin

Pfiesteria piscicida is a dinoflagellate which has a lethal effect on fish and also causes a syndrome of toxic effects in humans. Cognitive impairment is a prominent aspect of Pfiesteria's toxicity, and this neurocognitive effect resulting from toxin exposure has been demonstrated previously in a rat model. Four experiments are presented here, which replicate, confirm and extend some of the initial research and also show that similar cognitive deficits result from exposure to the toxin of another species, Pfiesteria shumwayae. Rats were given intraperitoneal injections of filtered water taken from toxic Pfiesteria cultures and tested in the radial arm maze (RAM). In two experiments, exposure to toxin from either species (piscicida or shumwayae) retarded acquisition of RAM performance in a non-interrupted win-shift RAM paradigm. A scopolamine challenge showed increased vulnerability to anticholinergic effects in exposed rats, even after nondrugged RAM performance was not different from controls. A third experiment featured a more difficult RAM test which included a 150-min interruption-delay. Toxin exposure also degraded performance in this version of the RAM, and the impairment was potentiated by the scopolamine challenge. The fourth experiment demonstrated retarded learning of the reversal of a RAM procedure which tested reference memory. In agreement with earlier research, these results indicate that Pfiesteria toxin interferes with the learning required to adapt to changing behavioral requirements. They also demonstrate that a latent toxin-produced CNS dysfunction persists after behavior appears normal, as revealed by potentiation of scopolamine's impairment of efficient RAM performance.

Comparative culture and toxicity studies between the toxic dinoflagellate Pfiesteria piscicida and a morphologically similar cryptoperidiniopsoid dinoflagellate

A series of fish bioassays using cultures of the toxic dinoflagellate, Pfiesteria piscicida and a cryptoperidiniopsoid dinoflagellate indicated various degrees of toxicity for Pfiesteria piscicida and no toxicity by the cryptoperidiniopsoid. P. piscicida maintained toxicity in the presence of live fish, and this toxicity was perpetuated following a series of inoculations to other culture vessels. Differences in the onset and magnitude of the fish deaths occurred, requiring 16 days for the initial fish death when using P. piscicida from a culture that had previously been maintained on algal cells, to kills within hours when using a culture that had recently (previous day) killed fish. Autopsies of moribund fish from the test and control fish bioassays indicated a general lack of bacterial infection, which ensued following death of other autopsied fish. Moreover, bacterial comparisons of waters in the fish bioassay and control fish cultures indicated that similar bacterial concentrations were present. Neither oxygen or ammonia levels were determined to be factors in the fish death. Life stages of a cryptoperidiniopsoid dinoflagellate from Virginia estuaries were also identified, including motile zoospore, gametes, planozygote, amoebae, and cyst stages. The cryptoperidiniopsioid did not initiate fish deaths in bioassays conducted over a 14-week period at zoospore concentrations of ca. 700-800 cells ml(-1). Elemental X-ray analysis of the scales from cysts of this dinoflagellate and P. piscicida indicate that they both contain silicon. Overall, the data from this study demonstrate that the cryptoperidiniopsoid possesses several similar life stages and feeding patterns as P. piscicida, but was not toxic to fish.

Phototoxicity of argon laser irradiation on biofilms of Porphyromonas and Prevotella species

Species of Prevotella (Pr.) and Porphyromonas (Po.) and other microorganisms were cultivated as biofilms on agar medium and examined for their susceptibility to argon laser irradiation (continuous mode; wavelengths, 488-514 nm; fluences, 20-200 J cm(-2)). Fluences of 35 to 80 J cm(-2) inhibited biofilm growth in Po. endodontalis, Po. gingivalis, Pr. denticola, Pr. intermedia, Pr. melaninogenica and Pr. nigrescens. A fluence of 70 J cm(-2) did not affect biofilm growth in species of Bacillus, Candida, Enterobacter, Proteus, Pseudomonas, Staphylococcus and Streptococcus. The phototoxic effects of argon laser irradiation against Prevotella and Porphyromonas species were: (1) caused by the radiation alone; (2) modified by biofilm age; (3) dependent on the presence of atmospheric oxygen; (4) influenced by medium supplements of hemin, hemoglobin and blood; (5) greater when compared with other microbial species; (6) demonstrated without augmentation with an exogenous photosensitizer; and (7) apparently unrelated to the protoporphyrin content of the cells. Overall, these in vitro findings suggest that low doses of argon laser radiation may be effective in the treatment and/or prevention of clinical infections caused by biofilm-associated species of Prevotella or Porphyromonas.

Sensitivity of Porphyromonas and Prevotella species in liquid media to argon laser

The phototoxicity of argon laser irradiation was studied in aqueous suspensions of Porphyromonas endodontalis (American Type Culture Collection [ATCC] 35406), Porphyromonas gingivalis (ATCC 33277), Prevotella denticola (ATCC 33184) and two strains of Prevotella intermedia (ATCC 15033 and 49046), all "black-pigmented bacteria," BPB, that accumulate cellular porphyrins. Several of these species have been implicated in the etiology of periodontal disease. Non-black-pigmented bacteria were also studied to test the specificity of irradiation as a potential photodynamic treatment for periodontal infections. Cell suspensions were irradiated with an argon laser at fluences of 20-200 J/cm2. When cultured in hemin-supplemented media, ATCC 15033 was the most sensitive to irradiation. However, a second strain of the same species (ATCC 49046) was resistant. The photosensitivity of other species ranked ATCC 33277 > 35406 = 33184 = 35496. When hemin was replaced in media by hemoglobin, ATCC 33277 became resistant to irradiation. Protoporphyrin IX content in BPB cells was shown not to be a major factor determining photosensitivity. Oxygen was required during irradiation for BPB species to be affected. Non-black-pigmented bacteria were much less sensitive to irradiation than BPB.

Decline in number of Na-K pumps on low-K+ sheep reticulocytes during maturation is modulated by Lp antigen

The number of the Na-K pumps on sheep red blood cells declines markedly during cell maturation. In addition, in red blood cells of the low-K+ (LK) phenotype, there is an increase during maturation in the affinity of the pumps for intracellular K+. This increase does not occur in cells of the high-K+ (HK) phenotype. This HK/LK polymorphism is associated with the M/L blood group antigen system. The Lp antigen, which is on only LK cells, promotes the increase in affinity for K+ [Am. J. Physiol. 265 (Cell Physiol. 34): C99-C105, 1993]. Mature LK cells have fewer pumps than mature HK cells. The present study shows that the Lp antigen also promotes the loss of pumps in LK cells. The evidence was that modification of the Lp antigen of immature LK red blood cells either with anti-Lp antibody or by trypsinization diminished the loss of pumps during culture in vitro (numbers determined from [3H]ouabain binding). Confirmation came from demonstration of the decline during maturation of the amount of the alpha-subunit of the Na-K pump (measured by immunoblotting), which was also retarded by pretreatment with anti-Lp or trypsin. Comparisons of the relative amounts of Lp antigen on immature and mature LK cells showed that there is little decline in number of antigens during maturation. Therefore there is an increase in the antigen-to-pump ratio during maturation even though an association between pumps and antigens is necessary for the loss of pumps.

The effect of antibodies to subunit V of cytochrome oxidase on cyanide inhibition of electron transfer

Binding of antibodies raised against subunit V of mammalian cytochrome oxidase to the intact membranous enzyme is redox-sensitive, suggesting the existence of 'open' and 'closed' protein conformers (Freedman, J.A., Cooper, C.E., Leece, B., Nicholls, P. and Chan, S.H.P. (1988) Biochem. Cell Biol. 66, 1210-1217). Similar open and closed states for the oxygen-reacting site have been proposed to explain cyanide binding kinetics (Jensen, P., Wilson, M.T., Aasa, R. and Malmström, B.G. (1984) Biochem. J. 224, 829-837). We therefore examined cyanide inhibition of oxidase activity polarographically and spectrophotometrically using soluble oxidase preincubated with and without anti-subunit V or non-immune rabbit gamma-globulin. The subunit-specific antibody decreased the cyanide 'on' rate and essentially eliminated the rapid phase of cyanide binding. We conclude that (i), bound antibody blocks HCN binding; (ii), antibody and HCN probably bind to the same conformation of the oxidase and (iii), the 'open'-'closed' conformation change that modulates binding of HCN may be similar to that which modulates antibody binding. The results are consistent with some reciprocating models of electron transfer and energy transduction by the oxidase (cf., Wikström, M.K.F., Krab, K. and Saraste, M. (1981) Cytochrome Oxidase: A Synthesis).

Differentiation of Na(+)-K+ pumps of low-K+ sheep red blood cells is promoted by Lp membrane antigens

Na(+)-K+ pumps of red blood cells from sheep of the low-K+ (LK) phenotype undergo differentiation during circulation, manifested in part by a striking increase in sensitivity to inhibition by intracellular K+ (Ki). Pumps of red blood cells from sheep from the allelic phenotype, high K+ (HK), do not undergo this type of maturation. The hypothesis was tested that the Lp antigen, found on LK but not HK cells, is responsible for the maturation of LK pumps. Lp antigens have been shown to inhibit LK pumps because anti-Lp antibody stimulates the pumps by relieving inhibition by the antigen. Lp antigens were recently shown to be molecular entities separate from Na(+)-K+ pumps [Xu, Z.-C., P. Dunham, J. Munzer, J. Silvius, and R. Blostein. Am. J. Physiol. 263 (Cell Physiol. 32): C1007-C1014, 1992]. The test of the hypothesis was to modify the Lp antigens of immature LK red blood cells with two kinds of treatments, anti-Lp antibody and trypsinization (which cleaves Lp), and to observe the effects of these treatments on maturation of pumps during culture of the cells in vitro. Both of these treatments prevented the maturation of the kinetics of the pumps to the Ki-sensitive pattern, supporting the hypothesis that interaction of the pumps with Lp antigens is responsible for the maturation of the pumps. Strong supportive evidence came from experiments on Na(+)-K+ pumps from rat kidney delivered into immature LK sheep red blood cells by microsome fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of systemic immune complexes, complement activation, and antibodies to Pseudomonas aeruginosa lipopolysaccharide and exotoxin A with mortality in cystic fibrosis

The relevance of circulating immune complexes, plasma complement activation, and serum antibodies against discrete antigens of Pseudomonas aeruginosa, to the clinical course in patients with cystic fibrosis (CF) is unknown. We related these factors to outcome in 49 patients with CF colonized by P. aeruginosa, comparing 14 who died of lung disease with 35 survivors of similar age and duration of colonization, as well as 9 uncolonized patients with CF, 24 patients with other bronchorrheic lung disease, and 10 healthy control subjects. The patients with CF colonized by P. aeruginosa who died had a higher incidence of immune complexes than did survivors (71 versus 40%, p less than 0.05). Moreover, C4 activation was highly associated with immune complexes and mortality (p less than 0.001 for each). Those who died also had much higher levels of IgG antibodies to P. aeruginosa lipopolysaccharide (LPS) and exotoxin A than did survivors colonized by P. aeruginosa (p less than 0.005 and p = 0.01, respectively), whereas both groups had similar levels of P. aeruginosa sonicate, elastase, alkaline protease, and endotoxin core antibodies. We conclude that increasing levels of serum IgG antibodies to P. aeruginosa LPS and exotoxin A and the presence of systemic immune complexes and complement activation are associated with poor prognosis in CF, and may provide useful noninvasive markers for studying the possible immunopathogenesis of CF lung disease.

Function and cell distribution of KC-1, a novel natural killer cell-associated antigen

Natural killer (NK) cell have been implicated in immune responses to tumor and viral antigens. We describe here a monoclonal antibody, anti-KC-1, that blocks lysis of NK targets by fresh but not activated NK cells. Anti-KC-1 has no effect on cytotoxic T lymphocyte activity or on antibody-dependent cellular cytotoxicity. This antibody may be useful in the analysis of NK cell activation and the mechanism of lysis.

Function and cell distribution of KC-1, a novel natural killer cell-associated antigen

Natural killer (NK) cell have been implicated in immune responses to tumor and viral antigens. We describe here a monoclonal antibody, anti-KC-1, that blocks lysis of NK targets by fresh but not activated NK cells. Anti-KC-1 has no effect on cytotoxic T lymphocyte activity or on antibody-dependent cellular cytotoxicity. This antibody may be useful in the analysis of NK cell activation and the mechanism of lysis.