Estimation of inspiratory effort using airway occlusion maneuvers in ventilated children: a secondary analysis of an ongoing randomized trial testing a lung and diaphragm protective ventilation strategy

BACKGROUND

Monitoring respiratory effort in ventilated patients is important to balance lung and diaphragm protection. Esophageal manometry remains the gold standard for monitoring respiratory effort but is invasive and requires expertise for its measurement and interpretation. Airway pressures during occlusion maneuvers may provide an alternative, although pediatric data are limited. We sought to determine the correlation between change in esophageal pressure during tidal breathing (∆Pes) and airway pressure measured during three airway occlusion maneuvers: (1) expiratory occlusion pressure (Pocc), (2) airway occlusion pressure (P0.1), and (3) respiratory muscle pressure index (PMI) in children. We also sought to explore pediatric threshold values for these pressures to detect excessive or insufficient respiratory effort.

METHODS

Secondary analysis of physiologic data from children between 1 month and 18 years of age with acute respiratory distress syndrome enrolled in an ongoing randomized clinical trial testing a lung and diaphragm protective ventilation strategy (REDvent, R01HL124666). ∆Pes, Pocc, P0.1, and PMI were measured. Repeated measure correlations were used to investigate correlation coefficients between ∆Pes and the three measures, and linear regression equations were generated to identify potential therapeutic thresholds.

RESULTS

There were 653 inspiratory and 713 expiratory holds from 97 patients. Pocc had the strongest correlation with ∆Pes (r = 0.68), followed by PMI (r = 0.60) and P0.1 (r = 0.42). ∆Pes could be reliably estimated using the regression equation ∆Pes = 0.66 [Formula: see text] Pocc (R2 = 0.82), with Pocc cut-points having high specificity and moderate sensitivity to detect respective ∆Pes thresholds for high and low respiratory effort. There were minimal differences in the relationship between Pocc and ∆Pes based on age (infant, child, adolescent) or mode of ventilation (SIMV versus Pressure Support), although these differences were more apparent with P0.1 and PMI.

CONCLUSIONS

Airway occlusion maneuvers may be appropriate alternatives to esophageal pressure measurement to estimate the inspiratory effort in children, and Pocc represents the most promising target.

TRIAL REGISTRATION

NCT03266016; August 23, 2017.

Self-assembly of 33-mer gliadin peptide oligomers

The 33-mer gliadin peptide, LQLQPF(PQPQLPY)3PQPQPF, is a highly immunogenic peptide involved in celiac disease and probably in other immunopathologies associated with gliadin. Herein, dynamic light scattering measurements showed that 33-mer, in the micromolar concentration range, forms polydisperse nano- and micrometer range particles in aqueous media. This behaviour is reminiscent of classical association of colloids and we hypothesized that the 33-mer peptide self-assembles into micelles that could be the precursors of 33-mer oligomers in water. Deposition of 33-mer peptide aqueous solution on bare mica generated nano- and microstructures with different morphologies as revealed by atomic force microscopy. At 6 μM, the 33-mer is organised in isolated and clusters of spherical nanostructures. In the 60 to 250 μM concentration range, the spherical oligomers associated mainly in linear and annular arrangements and structures adopting a "sheet" type morphology appeared. At higher concentrations (610 μM), mainly filaments and plaques immersed in a background of nanospherical structures were detected. The occurrence of different morphologies of oligomers and finally the filaments suggests that the unique specific geometry of the 33-mer oligomers has a crucial role in the subsequent condensation and organization of their fractal structures into the final filaments. The self-assembly process on mica is described qualitatively and quantitatively by a fractal diffusion limited aggregation (DLA) behaviour with the fractal dimension in the range of 1.62 ± 0.02 to 1.73 ± 0.03. Secondary structure evaluation of the oligomers by Attenuated Total Reflection FTIR spectroscopy (ATR-FTIR) revealed the existence of a conformational equilibrium of self-assembled structures, from an extended conformation to a more folded parallel beta elongated structures. Altogether, these findings provide structural and morphological information about supramolecular organization of the 33-mer peptide, which might offer new perspectives for the understanding and treatment of gliadin intolerance disorders.

Understanding recognition and self-assembly in biology using the chemist's toolbox. Insight into medicinal chemistry

Medicinal chemistry is intimately connected with basic science such as organic synthesis, chemical biology and biophysical chemistry among other disciplines. The reason of such connections is due to the power of organic synthesis to provide designed molecules; chemical biology to give tools to discover biological and/or pathological pathways and biophysical chemistry which provides the techniques to characterize and the theoretical background to understand molecular behaviour. The present review provides some selective examples of these research areas. Initially, template dsDNA organic synthesis and the spatio-temporal control of transcription are presenting following by the supramolecular entities used in drug delivery, such as liposomes and liquid crystal among others. Finally, peptides and protein self-assembly is connected with biomaterials and as an important event in the balance between health and disease. The final aim of the present review is to show the power of chemical tools not only for the synthesis of new molecules but also to improve our understanding of recognition and self-assembly in the biological context.

Water and sanitation associated with improved child growth

OBJECTIVE

To examine the relation between household water and sanitation, and the risk of stunting and reversal of stunting in Khartoum and Crezira regions, Sudan.

DESIGN

Prospective cohort study.

SETTING

A total of 25 483 children aged 6-72 months from rural Sudan enrolled in an 18-month field trial in 1988 to study the effect of vitamin A supplementation on child health and survival.

RESULTS

The mean height-for-age z-scores at baseline and the end of study were -1.66 and -1.55, respectively, for the group with water and sanitation facilities, and -2.03 and -1.94 for the group without water and sanitation, after adjustment for age, region, gender, mother's literacy, intervention group (vitamin A vs placebo), family wealth, breastfeeding and cleanliness. Among children of normal height-for-age at baseline, the risk of stunting (<-2 height-for-age z-score) was lowest in the group that came from homes that had both water and sanitation compared to children from homes without these facilities (multivariate RR=0.79, 95% CI 0.69-0.90). Among children stunted at baseline, those coming from homes with water and sanitation had a 17% greater chance of reversing stunting than those coming from homes without either facility (adjusted RR=1.17, 95% CI 0.99-1.38). We did not detect a synergistic association between access to water and sanitation.

CONCLUSIONS

Water and sanitation are independently associated with improved growth of children.

SPONSORSHIP

None.

Biodegradation of phenol in a continuous process: comparative study of stirred tank and fluidized-bed bioreactors

The paper presents the main results obtained from the study of the biodegradation process of phenol by a pure culture of Pseudomonas putida ATCC 17484. The experimental work was carried out in two different systems: a stirred tank where cells grew as a suspended culture and a fluidized bed where cells were immobilized within calcium alginate gel beads. The influence of the hydraulic residence time (HRT) and organic loading rate on the removal efficiency of phenol was determined for both bioreactors. Also, the stability of the fluidized-bed bioreactor (FBB) in terms of its ability to withstand sudden phenol overdoses is also reported. Experimental values indicated that both bioreactors showed high phenol degradation efficiencies, higher than 90%, even for a phenol loading rate in the influent as high as 4 g phenol/l day. The FBB showed better performance than the suspended-culture bioreactor due to its better control and because it could operate with lower HRT.

Reduced visual resolution acuity and cerebral white matter damage in very-low-birthweight infants

Neonatal cerebral white matter echolucencies predict visual resolution acuity deficits in very-low-birthweight (VLBW) infants. We examined maternal sociodemographic, lifestyle, intrapartum, infant birth/perinatal, and ocular motor/refractive characteristics to determine whether they accounted for this association in infants who were tested once between postnatal age 25 and 56 weeks (corrected for gestational age at birth). Cranial ultrasound scans were read by consensus to identify echolucency in a population of VLBW infants with no known ocular abnormalities. Visual resolution acuity was measured with the Acuity Card Procedure (ACP) in 14 infants with echolucency and compared with that of 81 VLBW infants born in the same hospitals with normal ultrasound scans. In time-oriented logistic regression models, echolucency remained a consistent predictor of abnormal visual resolution acuity after adjustment for covariates in three developmental periods (pre-, peri-, and postnatal). Odds ratios ranged from 19.3 (95% confidence interval, 4.5 to 82.2; p=0.001) to 10.4 (95% confidence interval, 1.3 to 81.9; p=0.03). Reduced visual resolution acuity in VLBW infants appears to be due to cerebral white matter damage.

Tomato intake in relation to mortality and morbidity among Sudanese children

The intake of foods that contain high levels of antioxidants may counteract the adverse effects of oxidative stress and lead to improved immune function and reduced risk of infectious disease. We prospectively examined the relationship between the consumption of tomatoes, a rich source of antioxidants, and mortality and diarrheal and respiratory morbidity rates among 28,753 children who were 6-60 mo old and enrolled in a longitudinal study in the Sudan. Children in each household were visited every 6 mo for a maximum of four visits. At each round, mothers recalled whether a child had consumed tomatoes in the previous 24 h. Events (death or morbidity) reported at each round were prospectively allocated according to the number of days of tomato intake. Intake of tomatoes for 2 or 3 d compared with none was associated, respectively, with 48% (relative risk, 0. 53; 95% confidence interval, 0.30-0.91) and 83% (0.17; 0.04-0.72) reductions in morality rates (P: for trend = 0.002). The association between tomato use and death remained statistically significant (P: for trend = 0.004), even after further adjustment for total vitamin A intake. Tomato intake was also associated with a reduced risk of death associated with diarrhea in the week preceding death (P: for trend = 0.009) or fever (P: for trend = 0.04). Intake of tomatoes was also inversely and significantly associated with the risks of diarrheal and respiratory infections. Our data suggest that tomatoes may be beneficial for child health but also emphasize the general importance of food-based approaches to the prevention of micronutrient malnutrition and protection of the health of children in developing countries.

Dietary vitamin A intake and nondietary factors are associated with reversal of stunting in children

We examined prospectively the associations between dietary vitamin A intake, nondietary factors and growth in 8174 Sudanese children ages 6-72 mo who were stunted at the start of follow-up. All subjects were weighed and measured at baseline and at 6-mo intervals for 18 mo of follow-up. Dietary vitamin A intake during the prior 24 h was assessed using recall of vitamin A-containing foods at baseline and 6-mo intervals. We examined the association of dietary vitamin A intake with growth and the incidence of recovery of stunting after controlling for age, sex, breast-feeding status and socioeconomic variables. We found that carotenoid intake was associated with a greater incidence of reversal of stunting. Children in the highest quintile grew 13 mm more during the study period than children in the lowest quintile [95% confidence interval (CI): 0-25 mm] in multivariate analyses. The relative risk (RR) of recovery associated with vitamin A intake was greater in infants up to 1 y old (RR = 3.3, CI: 0.9-11.7) than in children > or =3 y of age (RR = 1.0, CI: 0.8-1. 3) (P:-value for interaction = 0.08). Diets rich in carotenoids may increase the rate of recovery from stunting in children. Dietary effects on growth might be strongest among very young children and those who have been most malnourished. Age, sex, breast-feeding status, socioeconomic status and severity of baseline stunting also were associated with reversal of stunting in this population.

Undernutrition and childhood infections: a prospective study of childhood infections in relation to growth in the Sudan

The relationships between both diarrhoea and respiratory infections and linear and ponderal growth were prospectively examined among 28 753 Sudanese pre-school children. Childhood infections were significantly and inversely associated with attained height and attained weight and gain in height and weight over a 6-mo period. They were significantly and positively associated also with stunting after adjusting for age, gender, socio-economic status, dietary variables and previous morbidity. Attained height was on average 17 mm lower (95% CI [-19 -15]) for children with diarrhoea and 11 mm lower (95% CI [-3 -9]) for children with complicated cough than for those without these symptoms. The association between morbidity and attained weight was significant for diarrhoea and complicated cough, but the differences between children with and without symptoms were negligible. The risk of being stunted 6 mo later was 1.38 times (95% CI [1.20 1.59]), 1.29 times (95% CI [0.97 1.72]) and 1.32 times (95% CI [1.13 1.54]) greater among normally-nourished children with diarrhoea, febrile diarrhoea and fever, respectively, than among children without these symptoms. The difference in attained height between children with diarrhoea or complicated cough and those without symptoms increased with age, and was larger among the non-breastfed children compared with breastfed children.

CONCLUSION

The results underline the need to reduce child morbidity to prevent the impairment of growth and development.

Undernutrition in relation to childhood infections: a prospective study in the Sudan

OBJECTIVE

The aim of the study was to examine the relationships between nutritional status and diarrhoea and respiratory infections.

DESIGN

Prospective cohort study within the framework of a randomized double-blind placebo-controlled intervention trial.

SETTING

In rural communities in the Khartoum and Gezira regions, in Northern Sudan.

SUBJECTS

28,753 Sudanese pre-school children between 6 months and 6 y old.

METHODS

Relative risks of subsequent diarrhoea and respiratory infections in relation to nutritional status measured by anthropometry (Z-scores of height-for-age (H/A), weight-for-height (W/H), and weight-for-age (W/A), which reflect stunting, wasting and underweight, respectively) were estimated using odds ratios from logistic regression adjusting for various covariates.

RESULTS

H/A, W/H and W/A were significantly and inversely associated with subsequent diarrhoea and febrile diarrhoea (P for trend <0.001) with risks being 2.00 times higher (95% confidence interval, CI (1.64, 2.43)) among children with W/A Z-scores below -4 Z, and 1.75 times higher (95% CI (1.56, 1.96)) among those with a W/A Z-score between -4 and -3 Z compared with children having a W/A Z-score > or =1. Age, gender, region of residence and seasonality modified these associations. Also, febrile cough was inversely associated with W/A and W/H (P<0.03), with risks ranging from 1.41 times higher (95% CI (1.02, 1.97)) to 1.21 times higher (95% CI (1.04, 1.41)) in the group of underweight children with W/A Z-scores below -4 and between -2 and -1 Z, all compared with normally nourished children (> or =-1 Z).

CONCLUSIONS

The reduction of severe but also mild and moderate undernutrition is necessary through nutrition, health and socio-economic improvement in order to prevent morbidity.

A randomized trial of vitamin A supplements in relation to mortality among human immunodeficiency virus-infected and uninfected children in Tanzania

OBJECTIVES

To determine whether vitamin A supplements result in reduced mortality among HIV-infected and uninfected children.

DESIGN

Randomized, double blind, placebo-controlled trial.

METHODS

Starting in April, 1993, we randomized 687 children age 6 months to 5 years who were admitted to the hospital with pneumonia. Children who were severely malnourished or had clinical signs of vitamin A deficiency were excluded. At baseline children received placebo or 400 000 IU (or half that for infants) of vitamin A, in addition to standard treatment for pneumonia. They received further doses of the same regimen 4 and 8 months after hospital discharge. Sera from children were tested for HIV antibodies by enzyme-linked immunosorbent assay and Western blot tests. For positive children <15 months of age, HIV infection was confirmed by amplified heat-denatured HIV-p24 antigen assays with confirmatory neutralization assays. HIV status was ascertained for 648 of 687 enrolled children. The mean duration of follow-up was 24.4 months (SD = 12.1).

RESULTS

Of 648 children 58 (9%) were HIV-infected. Compared with uninfected children, all-cause mortality was higher among HIV-infected children, as was mortality caused by pneumonia or diarrhea (P < 0.001 for each). Overall vitamin A supplements resulted in a 49% reduction in mortality [relative risk (RR), 0.51; 95% confidence interval (CI), 0.29 to 0.90, P = 0.02]. Vitamin A supplements reduced all-cause mortality by 63% among HIV-infected children (RR 0.37; CI 0.14 to 0.95, P = 0.04) and by 42% among uninfected children (RR 0.58, CI 0.28 to 1.19, P = 0.14). Vitamin A supplements were also associated with a 68% reduction in AIDS-related deaths (P = 0.05) and a 92% reduction in diarrhea-related deaths (P = 0.01).

CONCLUSION

Vitamin A deficiency, which is common among children in many developing countries, is particularly severe among HIV-infected children. Our findings indicate that vitamin A supplements, a low cost intervention, reduce mortality of HIV-infected children.

Vitamin A supplementation and severity of pneumonia in children admitted to the hospital in Dar es Salaam, Tanzania

Vitamin A deficiency and acute lower respiratory tract infections coexist as important public health problems in many developing countries. We carried out a randomized, double-blind, placebo-controlled trial to examine whether large doses of vitamin A given to Tanzanian children who are admitted to the hospital with nonmeasles pneumonia would reduce the severity of respiratory disease. Six hundred eighty-seven children were randomly assigned to receive either placebo or vitamin A [200 000 IU (60 mg retinol equivalents) for children > 1 y of age and 100000 IU (30 mg retinol equivalents) for infants] on the day of admission and another dose on the following day. Of the 346 children in the vitamin A group, 13 died in the hospital, compared with 8 of 341 children in the placebo group; the relative mortality was 1.63 (95% CI: 0.67, 3.97; P = 0.28). The mean number of days of hospitalization was the same in both groups (4.2 d). There were no differences between the vitamin A and placebo groups in the duration of hospital stay when examined within categories of children stratified by age, sex, breast-feeding status, nutritional status at baseline, or quartile of dietary vitamin A intake in the 4 mo before admission to the hospital. There were also no differences in the mean number of days of fever, rapid respiratory rate, or hypoxia, whether these endpoints were examined in the total number of subjects or in a subset with more severe clinical conditions at baseline. Large doses of vitamin A had no protective effect on the course of pneumonia in hospitalized Tanzanian children.

A longitudinal study of prolonged breastfeeding in relation to child undernutrition

BACKGROUND

In a number of studies prolonged breastfeeding was associated with a higher risk of undernutrition, although most of these studies are limited by their cross-sectional design which does not allow examination of temporal relationships between full weaning and undernutrition.

METHODS

The relationship between prolonged breastfeeding and child growth was examined prospectively among children under 36 months old who participated in a large cohort study. At baseline and at each of three 6-monthly follow-up visits breastfeeding status was assessed and all subjects were weighed and measured.

RESULTS

Undernourished children were more likely to be breastfed for a longer period of time compared with normal children. We found a small difference between breastfed and fully weaned children in the gain in height over the following 6-month period; however, breastfed children were likely to gain significantly less weight, particularly among children who were aged 6-12 months. Similar findings were noted when these associations were examined among children who were normally nourished at the time of breastfeeding assessment. The inverse association between breastfeeding status and weight gain was significantly larger among children of poor or illiterate mothers compared with children of relatively more affluent or literate mothers, respectively.

CONCLUSIONS

Our findings suggest that the inverse association is not causal, and may be explained by poorer complementary feeding among breastfed compared with weaned children. Children from poorer households and whose parents are illiterate are more likely to have less than adequate complementary feeding. The importance of adequate complementary feeding in the second half of infancy needs to be stressed in nutrition education programmes.

The effect of vitamin A supplementation on the growth of preschool children in the Sudan

OBJECTIVES

This study assessed the effect of vitamin A supplementation at 6-month intervals on child growth.

METHODS

Sudanese children (n = 28,740) 6 to 72 months of age were weighed and measured at baseline and at each of three follow-up visits.

RESULTS

Periodic vitamin A supplementation had no effect on the rate of weight or height gain in the total population or on the incidence of wasting, stunting, or wasting and stunting among children who were normally nourished at baseline.

CONCLUSIONS

Reducing poverty and improving access to adequate diets should remain the goals of programs designed to improve the nutritional status of malnourished populations.

Dietary vitamin A intake in relation to child growth

Severe deficits in ponderal and linear growth are problems of major public health significance among children in developing countries. We prospectively examined the association of dietary vitamin A intake with child growth among 28,740 Sudanese children ages 6-72 months. At baseline and at each 6-month visit, all subjects were weighed and measured. Dietary vitamin A intake during the prior 24 hours was assessed using recall of vitamin A-containing foods. Dietary vitamin A intake was associated with attained height and weight after controlling for age, sex, morbidity, and socioeconomic variables. Compared with children in the bottom quintile of intake, those in the top quintile were 11 mm taller [95% confidence interval (CI) = 8-13] and 237 gm heavier (95% CI = 153-320). Higher dietary vitamin A intake was also associated with reduced risk of stunting [relative risk (RR) for 5th vs 1st quintile = 0.7; 95% CI = 0.5-0.9] and wasting (RR = 0.7; 95% CI = 0.5-0.9). Adequate intake of foods containing vitamin A may improve child growth where vitamin A deficiency prevails, but this relation may not be due to vitamin A per se.

Risk factors of low dietary vitamin A intake among children in the Sudan

We examined the determinants of dietary vitamin A intake among Sudanese children, information which is important for designing effective interventions based on the dietary approach. Children under the age of two years were at greater risk of consuming a diet low in vitamin A compared with children who were five years or older. Compared with children from relatively affluent households, those from poorer households were about twice as likely to consume low levels of carotenoid or preformed vitamin A. Low vitamin A intake was also significantly associated with lack of running water, a latrine, radio, or television in the household, and inversely associated with maternal or paternal illiteracy and with cleanliness of the child subjectively assessed by the interviewer. As expected, breastfed children in the first two years of life were likely to consume lower levels of preformed vitamin A and carotenoid from food (excluding breast milk) compared with non-breastfed children. Low vitamin A intake was more prevalent in the dry months of the year. Efforts to increase accessibility to vitamin A containing food, combined with nutrition education campaigns and public health programmes directed at improving sanitation and reducing infection are necessary as part of the long-term solution to the problem of vitamin A deficiency.

A prospective study of malnutrition in relation to child mortality in the Sudan

We examined prospectively the relation between malnutrition and mortality among Sudanese children. A cohort of 28753 children between the ages of 6 mo and 6 y was examined every 6 mo for 18 mo. Two hundred thirty-two children died during 18 mo of follow-up (480624 child-months). Low weight-for-height was associated with an increased risk of mortality (P < 0.0001). Even children with Z scores between -1 and -2 were 50% more likely to die in the following 6 mo than were children with Z scores > -1 (multivariate relative mortality: 1.5; 95% CI: 1.1, 2.2). There was also an inverse relation between height-for-age and mortality (P < 0.0001). Among breast-fed children, the relative mortality associated with a Z score for weight-for-height of < -3 compared with > -2 was 7.3 (95% CI: 3.3, 15.9); among children not breast-fed, it was 26.0 (95% CI: 12.8, 53.0; P for interaction = 0.001). A strong and significant synergy was also found between infection and wasting or stunting as predictors of child mortality (P for interaction = 0.001 and 0.02. respectively). In developing countries, children who are below the customary cutoff point of -2 Z for weight-for-height may be at higher risk of death. Breast-feeding and reduction of morbidity should be advocated in programs designed to reduce malnutrition and mortality among children.

Dietary vitamin A intake and the incidence of diarrhea and respiratory infection among Sudanese children

The relationship of vitamin A deficiency and child survival has been documented in a number of studies but not in others, yet the relationship of vitamin A with child morbidity remains controversial. We prospectively examined the relationship of dietary vitamin A intake and the incidences of diarrhea and respiratory infection among 28,753 Sudanese children between the ages of 6 mo and 6 y. Total dietary vitamin A intake was strongly and inversely associated with the risk of diarrhea (multivariate risk in top relative to bottom quintile = 0.58, 95% confidence interval = 0.47-0.72); we also observed a strong inverse association with the risk of having cough and fever (0.60, 0.45-0.81). On the other hand, we noted a significantly positive association of dietary vitamin A intake and incidence of cough alone (1.69, 1.52-1.88), a sign that may be assocsated with a healthy respiratory epithelium. Vitamin A intake was also negatively associated with the risk of measles. These prospective data emphasize the importance of adequate dietary vitamin A intake to protect the health of children in developing countries.

Child nutrition and armed conflicts in Iraq

The object of the study was to assess the nutritional status of children 0-5 years, who were attending maternal and child health clinics in Basrah city, 6 months after the cessation of the Gulf War, and took the form of a cross-sectional study. The study population consisted of 723 children, the majority of whom were between 0 and 36 months of age, attending maternal and child health clinics (MCHC) in Basrah city for routine immunizations. Each MCHC was visited on a separate day and all children attending on that day were included in the study. A proportion (8 per cent) of the study population were wasted, most of them in the 12-24-month age category. Twenty-four per cent of the children were stunted. Stunting and low weight-for-age were significantly higher among children of low socio-economic households. Comparison of these data with an earlier nutritional survey in the area showed that the nutritional status of children in Basrah city has deteriorated as a result of successive armed conflicts. There is need to monitor the health and nutritional status of children, and take appropriate action in order to protect them.

Dietary vitamin A intake and the risk of mortality among children

Increased consumption of dietary vitamin A is advocated as a long-term solution to vitamin A deficiency. We prospectively examined the relationship of dietary vitamin A intake and child mortality among 28,753 Sudanese children aged 6 mo to 6 y, who participated in a trial of vitamin A supplementation. After 18 mo of follow-up, 232 children died. Total dietary vitamin A intake was strongly and inversely associated with risk of mortality. The age- and sex-adjusted relative risk (RR) of mortality for a comparison of children in extreme quintiles was 0.35 (95% CIs 0.21-0.60; P for trend over quintiles < 0.0001). Even after possible confounding by socioeconomic variables was adjusted for, vitamin A intake was significantly protective (multi-variate relative risk 0.53). Dietary vitamin A intake was especially protective among children who were wasted and stunted or who had diarrhea or cough. These prospective data support an important role of dietary vitamin A in reducing childhood mortality in developing countries.

Risk factors associated with xerophthalmia in northern Sudan

The prevalence of eye signs and symptoms of vitamin A deficiency was determined among 29,615 Sudanese children between 6 and 72 mo of age, in five rural areas of Khartoum and Gezira provinces. Of all children, 2.9% were vitamin A deficient, and of these > 90% had Bitot's spots. Bivariate associations were found between xerophthalmia and the rural councils where the children lived, household wealth, consumption of vitamin A-containing foods, child sex, child age and weight-for-height Z-scores. Multivariate analysis showed that the following factors made significant independent contributions to the risk of xerophthalmia: living in remote and arid regions, male gender, age, poverty of the household, and prevalence of diarrhea. On the other hand, less xerophthalmia was observed among children who during the 24 h preceding the survey had consumed dairy products or non-leafy vegetables containing vitamin A. Intervention programs aimed at increasing household income and promoting consumption of foods containing vitamin A should contribute to the reduction of vitamin A deficiency among Sudanese children.

Vitamin A supplementation and dietary vitamin A in relation to the risk of xerophthalmia

We examined the effect of 60-mg (200,000-IU) supplements of vitamin A administered every 6 mo on the incidence of xerophthalmia among preschool children who were free of eye symptoms and signs of vitamin A deficiency. We also prospectively studied the relationship of dietary vitamin A intake with the same endpoint. After 18 mo of follow-up, 400 children developed xerophthalmia during 80,104 child-periods of follow-up. Vitamin A supplementation only modestly reduced the risk of xerophthalmia (relative risk 0.88, 95% confidence interval 0.72-1.07, P = 0.19). On the other hand, total dietary vitamin A intake was strongly associated with reduced risk of xerophthalmia; the multivariate relative risk when children in extreme quintiles were compared was 0.38 (95% confidence interval 0.19-0.74; P for trend over quintiles = 0.002). These results emphasize the need for further data on factors that modify the bioavailability of large-dose vitamin A supplements. Increased consumption of inexpensive vegetables and fruits is highly likely to reduce significantly the risks of vitamin A deficiency, including nutritional blindness in developing countries.

Vitamin A supplementation and child mortality. A meta-analysis

OBJECTIVE

A two-part meta-analysis of studies examining the relationship of vitamin A supplementation and child mortality.

DATA SOURCES

We identified studies by searching the MEDLARS database from 1966 through 1992 and by scanning Current Contents and bibliographies of pertinent articles.

STUDY SELECTION

All 12 vitamin A controlled trials with data on mortality identified in the search were used in the analysis.

DATA EXTRACTION

Data were independently extracted by two investigators who also assessed the quality of each study using a previously described method.

DATA SYNTHESIS

We formally tested for heterogeneity across studies. We pooled studies using the Mantel-Haenszel and the DerSimonian and Laird methods and adjusted for the effect of cluster assignment of treatment groups in community-based studies. Vitamin A supplementation to hospitalized measles patients was highly protective against mortality (DerSimonian and Laird odds ratio, 0.39; 95% confidence interval, 0.22 to 0.66; P = .0004) (part 1 of the meta-analysis). Supplementation was also protective against overall mortality in community-based studies (DerSimonian and Laird odds ratio, 0.70; clustering-adjusted 95% confidence interval, 0.56 to 0.87; P = .001) (part 2 of the meta-analysis).

CONCLUSIONS

Vitamin A supplements are associated with a significant reduction in mortality when given periodically to children at the community level. Factors that affect the bioavailability of large doses of Vitamin A need to be studied further. Vitamin A supplements should be given to all measles patients in developing countries whether or not they have symptoms of vitamin A deficiency.

Vitamin A supplementation and child survival

Previous studies of the effect of 6-monthly vitamin A supplementation on child mortality have given conflicting results. In other trials, more frequent doses of vitamin A have significantly reduced mortality among children at risk of vitamin A deficiency. We have done a double-blind, placebo-controlled trial of vitamin A supplementation in the Sudan among 28,753 children aged 9-72 months at risk of vitamin A deficiency. Children were assigned to receive either 200,000 IU vitamin A and 40 IU vitamin E every 6 months (vitamin A group) or 40 IU vitamin E alone (placebo group). During the 18 months of follow-up, there were 120 deaths (8.4/1000) in the vitamin A group and 112 (7.9/1000) in the placebo group (relative risk 1.06, 95% confidence interval 0.82-1.37). Controlling for geographic site, round of observation, anthropometry, morbidity, dietary intake of vitamin A, sex, and all baseline differences between the two groups did not change the results. Children living in poor and unsanitary environments, younger children, and those sick, stunted, wasted, or consuming diets low in vitamin A were at a significantly higher risk of dying. The lack of an effect of large-dose vitamin A supplementation on mortality, despite a clear association between dietary vitamin A and mortality, underscores the need to identify factors that modify the efficacy of vitamin A supplements as a public-health measure. Reducing poverty, improvements in sanitation, and access to adequate diets should remain the main goals to improve child survival.

Age-specific responsiveness of weight and length to nutritional supplementation

Evaluation of the responsiveness of weight and length to supplementary feeding shows that the two periods of greatest response coincide with weaning (ages 3-6 mo) and peak incidence and duration of diarrheal disease (ages 9-12 mo). Analyses were done for seven consecutive nonoverlapping intervals comparing children randomly assigned to receive supplemental feeding from birth to age 36 mo or to serve as control subjects. Absolute responsiveness was greatest between ages 3-6 mo; supplemented infants grew 0.61 cm more and gained 162 g more than did unsupplemented infants (p less than 0.005). Relative to rates of growth, responsiveness was greatest between ages 9 and 12 mo (the period of peak diarrheal prevalence), followed by ages 3-6 mo (the period of weaning). Responsiveness to supplementation is thus directly related to age-dependent risk patterns for malnutrition. Targeting supplementation programs to coincide with periods of high nutritional risk should maximize their effectiveness in reducing malnutrition, though caution should be exercised to avoid disruption of breast-feeding.

Long-term effects of food supplementation and psychosocial intervention on the physical growth of Colombian infants at risk of malnutrition

280 Colombian infants at risk of malnutrition were randomly assigned to 1 of 4 experimental groups formed by the presence/absence of 2 interventions: (1) food supplementation for the entire family, from mid-pregnancy until the target child was 3 years old, and (2) a twice-weekly home-visiting program to promote cognitive development, from birth until age 3. All families received free medical care and were studied prospectively. At 3 years of age, children who had received food supplementation averaged 2.6 cm and 642 grams larger than controls. Home visiting and supplementation together reduced the number of children with severe growth retardation. 3 years after intervention (age 6), supplementation effects remained. Children in the home visit condition had become larger than controls, by 1.7 cm and 448 grams. The interactive effect to reduce stunting was marginally significant at this age, and the overall distribution of scores was improved. Other results suggest that changes in family functioning as well as biological mechanisms account for the observed pattern of results.

Nutritional supplementation: effects on child stunting because of diarrhea

Research has shown that the positive effect of nutritional supplementation on child growth in malnourished populations is small relative to the large negative effect of diarrheal disease. To test the hypothesis that the effects of supplementation and diarrhea are synergistic in that supplementation modifies the negative effect of diarrhea on linear growth, length and diarrheal morbidity were compared at 36 mo of age for two cohorts of Colombian children: supplemented from birth and unsupplemented. Among unsupplemented children diarrhea was negatively associated with length. Among supplemented children diarrhea had no effect on length and differed from that of unsupplemented children. Thus, supplementation completely offset the negative effect of diarrheal disease on length. Targeting supplementation programs to the critical period of high diarrheal prevalence among infants and young children should increase the effectiveness of such programs in preventing growth retardation associated with diarrhea.

The effects of nutritional supplementation on the diets of low-income families at risk of malnutrition

Protein-energy malnutrition in synergism with infection is a major problem for most developing countries, and inadequate food consumption is a critical factor in its development. Food supplementation programs can improve nutrient consumption but may also have unintended consequences. Changes in consumption of foods as well as nutrients need to be identified and evaluated. The effects of a food supplementation program on family diet patterns and protein-energy intake were investigated using data from nutritionally at risk families in Bogota, Colombia. Because food supplements are income transfers they need to substitute for purchases of similar food items. However, the results of our investigation reveal that food supplementation based on familiar foods that are part of the usual family diet are consumed in substantial quantities and result in net nutrient consumption increases. The food supplementation program increases consumption of preferred food items and introduces greater diversity into the family diet. These effects are enhanced when combined with a home education program.

Sex related effects of nutritional supplementation during pregnancy on fetal growth

Nutritional supplementation of low income women during pregnancy increased birth weight significantly only in the male offspring. No differences by sex were apparent in the amount of supplementation, length of gestation or maternal characteristics known to be associated with birth weight. Regression analysis revealed a significant supplementation by sex interaction. The fetal growth curve of the supplemented males was higher and roughly parallel to the curve of females, and showed an effect of supplementation prior to 35 weeks of gestation. These findings and those of other authors support the hypothesis that fetal growth of males towards the end of pregnancy is more rapid and hence more susceptible to adverse environmental influences than that of females. This is reflected in a reduction of the difference in birth weight in favor of males observed in well-nourished populations. It is postulated that male subjects therefore exhibit sensitivity to nutritional supplementation of their mothers during pregnancy.

Nutritional supplementation, maternal education, and cognitive development of infants at risk of malnutrition

Infants born to families at risk of malnutrition were studied prospectively from the beginning of the 3rd trimester of the mother's pregnancy until the child reached 3 yr of age to ascertain the effects of nutritional supplementation and/or a maternal education program on their cognitive development. Four hundred thirty-three families were assigned randomly to six groups: group A served as a control; group B received the supplement from the age of 6 months to 3 yr; group C received the supplement during the 3rd trimester of pregnancy and the first 6 months of the child's life; and group D received the supplement throughout the entire study period. In addition, group A1 was enrolled in a maternal education program but received no nutritional supplement and group B1 received both treatments. The Griffiths test of infant development was administered at 4, 6, 12, 18, 24, and 36 months of age, and the Corman-Escalona Einstein scale was administered at each age up to 18 months. Children who received food supplementation performed better than those who did not, especially on subtests that were primarily motoric. The effect of food supplementation on behavior appeared to be contemporaneous. In addition, the treatment effects were more pronounced for girls than for boys in this sample. Although these interventions reduced the gap in cognitive performance between lower and upper socioeconomic classes, a disparity nevertheless remained by the end of the study.

Food supplementation of pregnant women at risk of malnutrition and their newborns' responsiveness to stimulation

Pregnant women at risk of malnutrition were enrolled in a health care programme in Colombia, South America, and were randomly assigned to a group receiving supplementary food or to a control group at the beginning of the third trimester of pregnancy. There were no differences between the groups in social or nutritional variables. Supplementary food was found to have an effect on infants' reactions to mild aversive stimulation and their degree of irritability. Infants born to non-supplemented mothers generally responded more irritably to removal of a nipple and to the application of a cold disc to the abdomen. Female infants of non-supplemented mothers also recovered more slowly than the supplemented group from crying in response to both removal of nipple and the cold disc. The findings are believed to show a maturational effect of maternal diet during the last trimester of pregnancy.

Immunotitration of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in various physiological states

The immunotitration of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase [mevalonate:NADP+ oxidoreductase [CoA-acylating), EC 1.1.1.34], the major regulatory enzyme in cholesterol biosynthesis, by HMG-CoA reductase antiserum is described. This technique provides the advantage that one can rapidly measure relative changes in both enzyme concentration and enzyme activity in different physiological states by using enzyme samples all the way from crude liver microsomes to purified enzyme. Regarding the diurnal rhythm of HMG-CoA reductase, the major difference noted between animals killed near the middle of the dark period (D 4.5) compared to animals killed near the middle of the light period (L 4.5) was in the concentrations of HMG-CoA reductase present, rather than in the activity of the enzyme, with substantially more enzyme found near mid-dark. Cholestyramine treatment resulted in both an increased concentration of HMG-CoA reductase and a catalytically more active enzyme. On the other hand, cholesterol feeding resulted in both a decreased concentration of HMG-CoA reductase and a catalytically less active enzyme.

Nutritional supplementation and the outcome of pregnancy. II. Visual habituation at 15 days

Colombian women at risk of mild-to-moderate malnutrition were enrolled in a health care program and randomly assigned into nutritional supplementation and control groups at the beginning of the third trimester of preganancy. One hundred unsupplemented and 144 supplemented infants were tested at 15 days of age: a 2X2 checkerboard was presented eight times followed by a single presentation of a 6X6 checkerboard. Unsupplemented infants showed less initial attention followed by slower habituation and higher levels of movement than the supplemented infants. The observed effect of maternal nutritional supplementation during the last trimester of pregnancy on new-born attention was interpreted to be maturational in nature.

Nutritional supplementation and the outcome of pregnancy. I. Birth weight

Colombian women at risk of malnutrition were enrolled in a health care program and randomly assigned to supplementation and control groups at the beginning of the third trimester of pregnancy. The net dietary intake increments resulting from supplementation amounted to 155 cal and 20 g of protein per day. Supplementation had a significant effect on the mean birth weight of male infants, but not that of female infants; the mechanisms responsible for the sex differences remain to be elucidated. The randomized trial design of the experiment and the documented similarity between the experimental and control groups at the onset permit the conclusion that the observed differences were caused by the food supplementation program. The effect of supplementation on maternal weight gain and the association of the latter with birth weight strongly suggest that improved maternal nutrition mediated the effect on birth weight.

Effects of vagotomy with and without pyloroplasty on weight and food intake in rats

Bilateral truncal vagotomy performed in 13 rats reduced weight gain by 26% compared to controls, but also produced gastric distension. Addition of pyloroplasty was found to facilitate gastric drainage in vagotomized rats, and both procedures were then performed in 57 rats of both sexes and varying initial weights. When fed ad libitum, vagotomized animals maintained a weight 14-30% less than controls over periods of 30-300 days. When pair fed, normal rats and rats with vagotomy and pyloroplasty weighed the same. Various partial vagotomies had no effect on weight gain. It was concluded that vagotomy reduces weight gain in rats, that the reduction is the result of decreased food intake, and that the effect of vagotomy is probably not due to gastric distension.

Hypercholesterolemia and triglyceride secretion rates in monkeys fed different dietary fats

The influence of hypercholesterolemia on the triglyceride secretion rate was studied in both squirrel and cebus monkeys fed coconut oil, corn oil, or safflower oil. The triglyceride secretion rate (TGSR) was determined in vivo following the administration of Triton WR1339, which blocks the clearance of very low density lipoprotein (VLDL). Thus, the increase observed in circulating triglyceride after Triton administration presumably reflecte hepatic triglyceride (VLDL) secretion in the fasted state. The VLDL-TGSR was lowest in hypercholesterolemic monkeys and highest in those fed unsaturated fat diets and having a low serum cholesterol. In all instances, TGSR was inversely correlated with the plasma cholesterol concentration. While a definitive explanation for these observations must await further investigation, the possibility that circulating low density lipoprotein (LDL) acts to feed back on VLDL secretion is discussed. The decreased TGSR associated with the diet-induced cholesterolemia also implies clearance of VLDL is impaired under these conditions.

Effect of dietary fat on hepatic metabolism of 14C-oleic acid and very low density lipoprotein triglyceride in the gerbil

In order to compare in vitro and in vivo aspects of lipid metabolism and lipoprotein secretion associated with the hyperlipemia of saturated fat feeding, gerbils were fed a diet containing 15% coconut oil or safflower oil for 6 weeks. In vitro incorporation of fatty acid was determined by measuring 14C-oleic acid incorporation into hepatic lipis in liver fasting gerbils following Triton WR1339 injection. The plasma lipoprotein profile was assessed by agarose electrophoresis. Coconut oil produced a hypertriglyceridemia and hypercholesterolemia associated with the appearance of very low density migrating lipoprotein, not seen with the safflower oil. Coconut oil also increased the hepatic triglyceride content, enhanced 14C-oleic acid incorporation into total lipid, and favored fatty acid incorporation into triglyceride; safflower oil facilitated esterification of oleic acid into phospholipid. Triton blockade of gerbils fed safflower oil resulted in twice the triglyceride secretion rate of those fed coconut oil. Our interpretation of the data is that dietary polyunsaturated fat favors incorporation of fatty acids into phospholipid, enhances both triglyceride secretion and the plasma transport and clearance of triglyceride and cholesterol and that the hyperlipemia of coconut oil feeding reflects a reduced metabolic clearnace of circulating lipid associated with that dietary fat.

Diet therapy of diabetes. Description of a successful methodologic approach to gaining diet adherence

A multifaceted educational program was designed to maximize dietary adherence of twenty-three diabetic subjects in order to study two experimental diets for forty weeks. The results of the program showed that a high level of diet adherence was achieved in spite of the strict dietary guidelines. The success of the educational approach was also reflected in the high attendance rate (99 per cent of 270 subject visits) and the low voluntary attrition rate (4 per cent).

Five aspects of the over-all design were felt to have been of major importance in gaining subject cooperation: (1) the small, grouporiented learning process; (2) frequent intervals of follow-up; (3) feedback on laboratory data; (4) individualization of diet prescriptions; and (5) family involvement.

Since the majority of diabetics seen in medical clinics fail to follow their prescribed diets, the concepts and approach applied to this study may be applicable to the dietary management of diabetic patients. Such implications and specific recommendations are presented in this report.

Decreased response to insulin in adipose tissue during starvation. Effect of hypophysectomy and growth hormone administration

Fasting for twenty-four hours or longer reduced basal glucose oxidation and incorporation into lipid in rat adipose tissue. The “in vitro” effect of 50 and 100 μU./ml. insulin was also found to be significantly decreased. A ten-fold increase in insulin concentration increased glucose metabolism to levels comparable to those observed in tissues from fed rats. Hypophysectomy diminished markedly the difference in response to insulin between fed and fasted rats. Injection of 50 μgm. of growth hormone every twelve hours restored this difference. It is concluded that adipose tissue responsiveness to insulin is markedly reduced by fasting and that the hypophysis is implicated in this phenomenon. Growth hormone appears to be one of the factors that mediates this change in insulin response.

Passage of insulin and inulin across vascular membranes in the dog

The equilibration of IRI and NSILA between arterial plasma and lymph was studied at different sites in sixteen anesthetized dogs. Lymph was collected from the thoracic duct in one group, from the main hepatic lymph vessel in another, and from the leg lymphatic in a third group. No baseline gradients were observed between arterial serum and lymph IRI concentrations. Lymph/serum NSILA concentration ratios were 0.62 ± 0.29 for leg lymph, 0.66 ± 0.20 for thoracic duct lymph and 0.84 ± 0.63 for hepatic lymph. Two tests were carried out in each dog:

(1) IVGTT (0.5 gm./kg.) Evans Blue was injected concurrently in some cases. Net glucose disappearance rate and serum IRI and NSILA patterns were similar in the three groups. Serum IRI passed rapidly into hepatic and thoracic duct lymph reaching plateau levels of 40 and 35 μU. per ml. respectively within 15 min. Leg lymph glucose concentration increased immediately but IRI appearance was delayed: A plateau of 20 μU, per ml. was reached after 30 min. No significant passage of Evans Blue into paw lymph was observed. Glucose injection was followed by a significant decrease in serum NSILA. Hepatic and thoracic duct lymph NSILA levels decreased slightly but NSILA concentration remained unchanged in leg lymph.

(2) One hour after the first test 0.2 U. per kg. of pork insulin and 25 uc 14C-inulin were injected intravenously. The patterns of distribution of these two substances were similar. Both reached peak concentrations first in hepatic lymph then in thoracic duct lymph. In paw lymph their appearance was delayed and the maximum concentration achieved was lower. It is concluded that differences in capillary permeability are likely to determine in part the distribution of IRI and NSILA in body fluids and thus may influence their biological activity.