Characteristics and outcomes of children with enterostomy feeding tubes: A study of 325 children

OBJECTIVES

To examine the characteristics and outcomes of children with gastrostomy and gastrojejunostomy tubes inserted before age three years, and to identify the factors that predict removal of the enterostomy tubes within 12 months of insertion.

DESIGN

Case review of a consecutive sample of 325 medical records.

SETTING

A tertiary care paediatric hospital that is situated in a large metropolitan area.

PATIENTS

All outpatients and inpatients from birth to 36 months of age who had an enterostomy tube inserted from 1994 to 1996.

METHODS

No direct intervention was provided. In the subgroup of 203 patients with a follow-up period of at least 12 months after tube insertion, children whose tubes were removed within 12 months of insertion were compared with children who continued to receive tube feedings for 12 months or longer.

RESULTS

At the time of tube insertion, the median age of patients was six months; 47% of the children for whom data were available were failing to thrive. Although 66 (21%) of 321 patients for whom data were available had their tubes removed, only 25 of the 203 (12%) patients with a follow-up period of 12 months or more had their tubes removed within 12 months of insertion. Children whose tubes were removed less than 12 months after insertion differed from children whose tubes were not removed with respect to medical diagnosis (no children with cerebral palsy had their tubes removed versus 33% of children with cancer who had their tube removed). Most children with failure to thrive at the time of tube insertion were also failing to thrive at the time of tube removal.

CONCLUSION

Children with cerebral palsy are not likely to have enterostomy tubes removed within one year of insertion.

Dual fortification of salt with iron and iodine in women and children in rural Ghana

OBJECTIVE

To test the efficacy of double-fortified salt (DFS) on the anaemia and iodine deficiency (ID) status of women and their children.

DESIGN

Double-blind randomised controlled trial.

SETTING

Sekyere West District of Ghana.

SUBJECTS

In this eight-month trial, mildly anaemic or non-anaemic, non-pregnant, non-lactating women were randomised into three groups receiving: DFS plus weekly placebo (n = 61); iodised salt plus weekly 70 mg iron supplement (n = 65); or iodised salt (IS) plus weekly placebo (control group, n = 58). Correspondingly, their mildly anaemic and non-anaemic children aged 1-5 years were randomised into two groups receiving either the DFS (n = 23) or IS alone (control group, n = 59).

RESULTS

At the end of the intervention, prevalence of anaemia in women remained unchanged in the DFS or IS plus weekly iron supplement group, but significantly increased by 19.5% in the control group (P = 0.039). In children, prevalence of anaemia in the DFS group significantly decreased by 21.7% (P = 0.025) while no change was observed in the control group. ID decreased significantly in all groups of women (P < 0.001) and children (P < 0.05), with no difference among groups of women and children.

CONCLUSION

While the use of DFS prevented anaemia in women, it had a significant role in both the prevention and treatment of anaemia in children. Both the DFS and IS significantly reduced ID in women and children to a similar degree.

Improved adherence and anaemia cure rates with flexible administration of micronutrient Sprinkles: a new public health approach to anaemia control

BACKGROUND/OBJECTIVES

Despite repeated public commitments and availability of various forms of iron supplements, rates of anaemia in developing countries remain high. A major reason for this lack of success has been poor adherence. The objective of this study was to compare the effectiveness of daily and flexible administration of micronutrient Sprinkles on adherence, acceptability and haematological status among young children in rural Bangladesh.

SUBJECTS/METHODS

A sample of 362 children (haemoglobin (Hb)>or=70 g l(-1)) aged 6-24 months were cluster-randomized to receive 60 sachets of Sprinkles either (i) daily over 2 months; (ii) flexibly over 3 months; or (iii) flexibly over 4 months. With a flexible regimen, mothers/caregivers decided how frequently to use Sprinkles without exceeding one sachet per day. Adherence was assessed monthly by counting the number of sachets used and acceptability was evaluated through focus group discussions. Haemoglobin was measured at baseline, at the end of each intervention period and 6 months post-intervention.

RESULTS

Mean percent adherence was significantly higher in the flexible-4-month group (98%) compared to the flexible-3-month (93%) and daily-2-month (88%) groups (P<0.01). Most mothers found flexible administration to be more acceptable than daily due to perceived benefits of use. Hb at the end of intervention was significantly higher in the flexible-4-month group compared to the daily group (P=0.03). Anaemia prevalence decreased by 65% in the flexible-4-month group compared to 54% in the flexible-3-month and 51% in the daily-2-month groups. Percent of cured children who maintained a non-anaemic status 6 months post-intervention was significantly higher in the flexible-4-month (82%) and flexible-3-month (80%) groups than the daily-2-month (53%) group (P<0.05).

CONCLUSIONS

The adherence, acceptability and haematological response to flexible administration over 4 months were found preferable to daily.

Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease

BACKGROUND

The anti-inflammatory effects of n-3 (omega-3 fatty acids, fish oil) have been suggested to be beneficial in chronic inflammatory disorders such as inflammatory bowel disease.

OBJECTIVES

To systematically review the efficacy and safety of n-3 for maintaining remission in Crohn's disease (CD).

SEARCH STRATEGY

The following databases were searched from their inception without language restriction: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Healthstar, PubMed, and ACP journal club. Experts were contacted for unpublished data.

SELECTION CRITERIA

Randomized placebo-controlled trials (RCT) of n-3 for maintenance of remission in CD were included. Studies must have enrolled patients of any age group, who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil or n-3 given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups. The primary outcome was relapse rate and secondary outcomes were change in disease activity scores, time to first relapse and adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. Meta-analysis was performed using RevMan 4.2 software, weighted by the Mantel-Haenszel method. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed to address heterogeneity.

MAIN RESULTS

Four studies were eligible for inclusion. There was a non statistically significant benefit of n-3 therapy for maintaining remission (RR 0.64; 95%CI 0.4 to 1.03; P = 0.07). However, the studies were both clinically and statistically heterogeneous (P = 0.01, I(2) = 72%). Three studies used enteric coated capsules (positive effects) and one ordinary gelatin capsules (no advantage). Subgroup analyses of studies which used enteric coated capsules revealed a statistically significant benefit for maintenance of remission (RR 0.49; 95% CI 0.35 to 0.69; RD 0.31; 95% CI 0.19 to 0.43); number needed to treat to prevent relapse in 1 year was 3 (95% CI 2 to 5; I(2) = 19%). However, the total number of patients enrolled in these studies was small (n = 166). No significant adverse events were recorded in any of the studies and not enough data were available to analyze the other secondary outcomes.

AUTHORS' CONCLUSIONS

Omega 3 fatty acids are safe and may be effective for maintenance of remission in CD when used in enteric coated capsules. However, there are not sufficient data to recommend the routine use of n-3 for maintenance of remission in CD. The small number of patients in the included studies warrants further larger RCTs.

Fractional zinc absorption using a single isotope tracer

BACKGROUND

Fractional absorption of zinc (Zn) has been measured using dual isotopes of Zn given simultaneously. An oral test dose and an intravenous (i.v.) reference dose are administered, followed by the measurement of the double isotopic enrichment (E) in urine 48 h after administration. We postulated that an estimate of the %E in urine for a given i.v. dose of Zn may be used to eliminate the need for venipuncture and the second Zn isotope.

OBJECTIVES

To determine a constant (k) for the Zn enrichment of urine after i.v. administration of a dose of labeled Zn in Zn-replete subjects. To use 'k' to calculate fractional absorption of Zn, and to compare these values to values obtained using the standard dual isotope method.

DESIGN

Single-arm cohort.

SETTING

The Hospital for Sick Children, Toronto, Canada.

SUBJECTS

Twenty-three healthy adults were recruited from the Metropolitan Toronto area. Seventeen subjects completed the study.

INTERVENTIONS

A 2.29 mg i.v. dose of (67)Zn followed immediately by a 2.50 mg oral dose of (70)Zn.

RESULTS

Population mean percentage enrichment (%E) of (67)Zn in urine was 1.43 (95% CI 1.26, 1.60). The ratio of the i.v. dose to mean %E in urine (k) was estimated to be 1.60 mg (95% CI 1.43, 1.82). There was no difference in the mean fractional absorption of Zn calculated using the single compared to the dual isotope method: 12.58% (95% CI 2.22, 22.94) vs 12.68% (95% CI 4.52, 20.85), respectively (P=0.89). The correlation coefficient between the two methods was 0.81 (P<0.0001).

CONCLUSIONS

The dual isotope method may be replaced by using a constant (k) and a single oral dose of isotopic-enriched Zn to estimate fractional absorption of Zn within a population.

SPONSORSHIP

Gerber Products Company, Fremont, MI.

Developing and implementing food-based dietary guidance for fat in the diets of children

This article discusses the process by which a country can effectively solve health problems through recommended changes in the nutrient content of the diet. Each country must consider not only the development of scientific guidelines suitable for its population, but also strategies for effective food-based dietary guidance to achieve the goal. This is best done by integrating health and dietary goals when forming scientific guidelines and by developing effective partnerships among the many sectors that influence the food supply and food selection. Using fat intake in children as an example, this article describes the determinants of success in achieving the goals of science-based dietary guidelines through food-based dietary guidance.

Efficacy of meat and iron-fortified commercial cereal to prevent iron depletion in cow milk-fed infants 6 to 12 months of age: a randomized controlled trial

OBJECTIVE

To determine whether utilization of iron from infant cereal and pureed meat was sufficient to prevent iron depletion and/or anaemia in infants 6 to 12 months old fed whole cow milk (WCM) as their primary milk source.

DESIGN

Six-month-old infants were randomized into a treatment group (n = 43) receiving iron-fortified infant cereal (10.2 mg iron), pureed meat (0.75-1.7 mg iron) and WCM for six months or a control group (n = 54) receiving no dietary intervention. Haemoglobin < 110 g/L or ferritin < 10 micrograms/L (measured bi-monthly), confirmed in a second blood sample, defined end-points.

RESULTS

Proportion reaching end-point was similar between the treatment (3/43) and control infants (5/54) (p = 0.66). Infants not complying with the protocol were at greater risk of reaching end-point (p = 0.0002). Change in haemoglobin and ferritin across age was similar in both groups.

CONCLUSIONS

Iron deficiency is not a concern in WCM-fed infants after six months of age if iron-containing complementary foods are concurrently ingested.

Discontinuation of enterostomy tube feeding by behavioral treatment in early childhood: a randomized controlled trial

OBJECTIVE

To determine whether behavior therapy was more effective than nutritional therapy in obviating the need for enteral feeding in infants with resistance to feeding.

STUDY DESIGN

Sixty-four children aged 4 to 36 months who were tube fed for at least 1 month and had resistance to feeding were randomly assigned to either behavioral or nutritional interventions (32 per group). For 7 consecutive weeks subjects and their primary feeders attended a weekly clinic with 1 of 2 dietitians followed by 4 follow-up visits. The nutritional intervention provided structured schedules and routines to stimulate the hunger/satiety cycle. The behavioral intervention provided the same schedules and routines plus behavioral therapy (extinction). The primary outcome measure was the proportion of successes, defined as infants no longer requiring tube feeding at the third follow-up visit in each group (4(1/2) months after start of trial). The decision to discontinue tube feeding was made by an independent observer who used criteria defined before the study commencement.

RESULTS

Fifteen (47%) of 32 subjects in the behavioral group versus none in the nutritional group were successes (P <.001).

CONCLUSION

Behavior therapy is more efficacious in eliminating the need for tube feeding than nutritional counseling alone.

Iron is well absorbed by healthy adults after ingestion of double-fortified (iron and dextran-coated iodine) table salt and urinary iodine excretion is unaffected

Severe deficiencies of iron (Fe) and iodine (I) affect more than one third of the world's population. A table salt, fortified with I and Fe, would be useful in areas in which anemia and goiter coexist. However, interactions between the two minerals have prevented their simultaneous use as fortificants. A method has been developed to coat I with dextran such that after spraying onto table salt, Fe and I do not interact. Our objective was to determine the absorption of Fe and the urinary excretion of I from table salt when provided in meals designed to significantly inhibit or enhance Fe absorption. Subjects (n = 16) ingested Fe-enhancing and Fe-inhibiting meals containing 5 g of table salt with 0.39 micromol dextran-coated I as potassium iodide and 1 mg of Fe (ferrous fumarate labeled with 59Fe) per gram of salt. Subjects also received a reference dose of 3 mg of ferrous fumarate labeled with 59Fe to "correct" for interindividual variation in iron absorption at a later date. Measured by whole-body counting, Fe-absorption from the Fe-enhancing meal (36.2 +/- 12.0%, corrected; 13.5 +/- 13.8% uncorrected) was significantly higher than that from the Fe-inhibiting meal (7.4 +/- 11.3%, corrected; 4.0 +/- 8.4%, uncorrected) (P < 0.0001). Urinary excretion of iodine at baseline and postingestion were not significantly different (0.89 +/- 0.5 vs. 1.06 +/- 0.39 micromol/L, P < 0.47) and were within the normal range. We conclude that Fe was well absorbed but influenced by the composition of the meal and that urinary excretion of iodine was maintained in the normal range with dextran-coated iodine.

Disparity of serum transferrin receptor measurements among different assay methods

OBJECTIVE

To highlight differences in the quantification of transferrin receptor (TfR) concentration (a reliable index of iron deficiency) between three different assay methods.

DESIGN

Methods comparison of TfR measurements in 'elevated' and 'normal' human sera using the Ramco, Quantikine and 'Lab' assays.

SETTING

The Hospital for Sick Children, Toronto, Ontario, Canada.

SUBJECTS

Pooled TfR for elevated and normal human sera obtained from the Ramco TfR assay kit.

MAIN OUTCOME MEASURES

Differences between TfR concentrations in normal and elevated samples and repeatability for each assay method and limits of agreement in TfR quantification between assay methods.

RESULTS

The mean TfR concentrations for the elevated reference serum samples was higher than the normal reference samples within each individual assay (P < 0.001); however, measurement agreement between methods was poor.

CONCLUSIONS

Recognition of the relative differences in the values obtained from each of the assays should affect the interpretation of TfR concentration as an index of iron deficiency.

Percentile estimates for transferrin receptor in normal infants 9-15 mo of age

To establish percentile estimates of transferrin receptor (TfR) for healthy infants, plasma TfR was measured in 485 healthy infants 9-15 mo of age from Edmonton, Toronto, Montreal, and Halifax. Education and income of the sample families were reflective of the average family based on the 1991 census estimates. The mean (+/-SD) plasma TfR concentration was 4.4 +/- 1.1 mg/L. As expected in the infant population, there were no differences in TfR concentrations as a result of sex, and within this small age range there was no significant change across age. Furthermore, the TfR concentration in plasma was not associated with hemoglobin, serum ferritin, or free erythrocyte protoporphyrin. TfR has been shown to be a sensitive, quantitative measure of tissue iron deficiency not affected by inflammation and is potentially important in the diagnosis of iron deficiency, but there is a lack of normative data, particularly in infants, who are at highest risk of iron deficiency. If TfR proves useful in the diagnosis of iron deficiency, the current data will be useful as a reference standard for healthy infants.

Day-to-day variation of transferrin receptor and ferritin in healthy men and women

To determine the total day-to-day intraindividual variability of ferritin and transferrin receptor (TfR), we collected venous serum and plasma and capillary serum and plasma samples during 10 nonconsecutive days over a 4-wk period from a group of healthy men (n = 10) and women (n = 11) aged 19-46 y. On the basis of a method previously established in younger and older adults, biological (sigma 2 day) and analytical (sigma 2 rep) variance components were computed and summed to obtain the total day-to-day intraindividual variability (sigma 2 tot). The total day-to-day intraindividual CV (CVtot) was lower for TfR than for ferritin measurements. One to two discrete blood samples are required to accurately determine capillary and venous TfR, whereas capillary and venous ferritin, which have a higher CVtot, require three to six samples. Results from the current study showing the low biological and analytical variability of TfR support the use of this new test for assessing a person's iron status.

A review of the Canadian "Nutrition recommendations update: dietary fat and children."

A joint Working Group from the Canadian Paediatric Society and Health Canada met in the early 1990s to consider the applicability of recommendations to restrict total and saturated fat in children > or = 2 y of age. The Group weighed information from the literature on the nutritional needs for growth and development against evidence relating diet to risk of nutrition-related diseases. The Group concluded that the efficacy of the fat-restricted diet could not be assumed. There was no evidence that implementation of the diet would reduce illness in later life or provide benefit to children as children. Regarding safety, some children consuming self-selected diets with low fat intakes have lower energy intakes and food patterns that may compromise the intake of certain key nutrients. The primary recommendations of the Group were that the provision of adequate energy and nutrients to ensure adequate growth and development remains the most important consideration in the nutrition of children and that during the preschool and childhood years, nutritious food choices should not be eliminated or restricted because of fat content. Once linear growth has stopped, fat intake as currently recommended (30:10) is appropriate.

Determination of iron absorption using erythrocyte iron incorporation of two stable isotopes of iron (57Fe and 58Fe) in very low birthweight premature infants

Due to limited erythropoiesis, iron needs for the premature infant during the first 2 months of life are low. With the potential for increased use of erythropoietin in the preterm infant, iron requirements may become markedly higher. The ability of the preterm infant to absorb iron, therefore, becomes crucial. Previous studies using single stable isotopes of iron without metabolic balances were unable to quantitatively determine iron absorption since the percentage of absorbed iron appearing in the erythrocyte could not be measured. The objective of the current study was to determine iron absorption using the method of erythrocyte iron incorporation of two stable isotopes of iron given by the enteral and parenteral route to very low birth weight (VLBW) infants. Results obtained were compared to iron absorption values from studies using single isotopes and metabolic balance techniques. Six VLBW premature infants (gestational age 26.8 +/- 1.7 weeks, postnatal age 3.6 +/- 1.9 weeks, birth weight 863 +/- 117 g) were studied. Iron dosages were (i.v.) 0.15 mg/kg (57FeSO4) and (enteral) 1.5 mg/kg (58FeSO4). Erythrocyte isotope ratios, 57Fe/54Fe and 58Fe/54Fe, were determined by inductively coupled plasma mass spectrometry (ICP/MS) from single blood samples (100 microliters) collected before and after concurrent enteral (58Fe) and parenteral (57Fe) administration of isotopes. Only 17.8% of the i.v.-infused iron dose was incorporated into hemoglobin on day 15. Using a correction factor based on the percentage of i.v. iron (57Fe) incorporated into erythrocytes, the corrected incorporation of 58Fe was calculated to be 26.3 +/- 13.0% of the enteral dose of 58FeSO4.

Trace elements in nutrition for premature infants

Ten trace elements that are nutritionally essential include: zinc, copper, selenium, chromium, manganese, molybdenum, cobalt, fluoride, iodine, and iron. This article briefly reviews the biochemistry of these trace elements, describes clinical deficiency states, and provides a rationale for recommended enteral and parenteral intakes for preterm infants.

The influence of zinc-binding ligands in fetal circulation on zinc clearance across the in situ perfused guinea pig placenta

Although zinc is essential for normal fetal growth and development, little is known about factors that influence its transfer across the placenta. The in situ perfused guinea pig placenta model was used to study the influence of zinc-binding ligands in fetal circulation on maternofetal placental zinc transfer. A placenta of each anesthetized sow was perfused (on the fetal side) with a physiological perfusate via the umbilical vessels, with the fetus excluded. The sow was infused intravenously with 65Zn as a tracer of placental zinc clearance and with antipyrine as an indirect indicator of maternal placental blood flow. Maternal plasma and placental effluent samples collected at intervals were counted for 65Zn with a gamma counter, and the absorbance of nitrosated antipyrine was measured at 350 nm. The addition of physiological levels of zinc-binding ligands (albumin, L-histidine and L-cysteine) to the perfusate increased the relative maternofetal clearance of zinc across the placenta calculated as zinc clearance/antipyrine clearance [mean +/- SEM; 0.113 +/- 0.016 vs. 0.062 +/- 0.012; ligands vs. no ligands; n = 8; P less than 0.05]. The results suggest that the availability of zinc-binding ligands in fetal circulation is one determinant factor of placental zinc transfer.

The effect of zinc levels in fetal circulation on zinc clearance across the in situ perfused guinea pig placenta

Although zinc is essential for normal fetal growth and development, little is known about factors that influence its transfer across the placenta. The in situ perfused guinea pig placenta model was used to study the influence of the zinc concentration of fetal circulation on maternofetal placental zinc transfer. A placenta of the anaesthetized sow was perfused (on the fetal side) with a physiological perfusate via the umbilical vessels, with the fetus excluded. The sow was infused intravenously with 65zinc as a tracer of placental Zn clearance, and with antipyrine as an indirect indicator of maternal placental blood flow. Maternal plasma and placental effluent samples collected at intervals were counted for 65zinc by gamma counter, and the absorbance of nitrosated antipyrine was measured at 350 nm. Varying the mean zinc concentration in the perfusate from 0.176 to 1.87 mg/L had no effect on relative zinc clearance calculated as zinc clearance/antipyrine clearance (mean +/- SEM; 0.085 +/- 0.010 vs. 0.114 +/- 0.018; n = 6; p greater than 0.05). The results suggest that short-term changes in fetal zinc status do not influence placental zinc transfer.

Hepatic sulfur amino acid metabolism in rats with chronic renal failure

We recently demonstrated elevated plasma amino acid concentrations and abnormal responses to amino acid supplementation (e.g., elevated methionine and phenylalanine) in children with chronic renal failure (CRF). We also recently developed an improved model of CRF in which animals manifest abnormal tissue amino acid levels, marked anorexia and growth failure. The objective of the current study was to determine the etiology of elevations of sulfur amino acids in animals with chronic renal failure. Chronic renal failure, defined as creatinine clearance less than 30% of control values, was induced in male rats in a two-stage surgical procedure. Four groups were studied over 2, 4 and 6 wk: control (non-operated) control (sham-operated), pair-fed (sham-operated and pair-fed with uremics) and CRF. Animals with CRF were anorexic and growth-retarded. Although plasma sulfur amino acid levels tended to be lower in the uremic animals than in controls, hepatic tissue concentrations were higher. Methionine adenosyltransferase was higher, but cystathione synthase and cystathionase activities were not significantly different in rats with CRF compared to pair-fed controls. We conclude that uremia, not malnutrition, affected sulfur amino acid metabolism and that with CRF, a normal adaptive response to elevated methionine levels was occurring, sufficient to normalize sulfur amino acid pool size. Alternative causes of elevated sulfur amino acids must be sought.

Nutrient interactions with total parenteral nutrition: effect of histidine and cysteine intake on urinary zinc excretion

Because cysteine and histidine, two amino acids included in total parenteral nutrition regimens, bind zinc and increase its renal ultrafilterability, my objective was to quantify the effects of infusion of amino acids, including cysteine and histidine, on urinary zinc excretion. The effect of the infusion of high amounts of cysteine and no cysteine (100 mg/kg/day vs none) and of high and low amounts of histidine (165 vs. 95 mg/kg/day) on urinary zinc excretion was determined in 14 newborn infants receiving total parenteral nutrition who had similar zinc intakes (approximately 7 mumol/kg/day). After a 72-hour adaptation period, each infant's urine was collected for two 48-hour periods. Urinary zinc excretion during the high-dose histidine and cysteine infusion periods was significantly elevated compared with that during the no-cysteine and low-dose histidine periods. Therefore concurrent intakes of specific amino acids may have to be considered when zinc dosages are calculated.

Hepatic metallothionein as a source of zinc and cysteine during the first year of life

Metallothionein, a high cysteine-containing protein, can bind with both essential and nonessential metals and thus play an important role as a metal storage protein and also in the detoxification of toxic metals. Although in the human fetus, levels of trace minerals and metallothionein are very high, their postnatal changes are not well documented. The purpose of the present investigation, therefore, was to quantify the accumulation of metallothionein in premature and full-term infants during the first year of life and to identify factors affecting its accumulation. From 47 postmortem samples, it was determined that hepatic metallothionein levels were highest in newborn premature and full-term infants falling to levels found in older children by 4.4 months of age. Hepatic zinc levels were also highest in the youngest infants, falling with increasing postnatal age. There was a significant positive correlation between zinc and metallothionein at all ages. However, there was a negative correlation between hepatic metallothionein levels and cystathionase activity. Hepatic copper and metallothionein levels were unrelated. The renal concentration of metallothionein, zinc, and copper were significantly lower than corresponding hepatic levels. The fall in hepatic levels of zinc and metallothionein during the first months of life correspond to a period of negative zinc balance and low endogenous cysteine production in the newborn. Thus metallothionein may play an important role as a storage depot for these two essential nutrients during this critical period of active growth.

Amino acid intake and urinary zinc excretion in newborn infants receiving total parenteral nutrition

Zinc deficiency is well described in infants on total parenteral nutrition (TPN). Urinary Zn excretion is the major source of Zn loss in the parenterally fed infant; factors causing increased zincuria will predispose the infant to Zn deficiency and affect the recommended Zn intake dosage. Histidine, threonine, and lysine have been shown to bind Zn increasing its renal ultrafilterability. The effect of the infusion of high and low lysine (206 +/- 34 vs 158 +/- 38 mg.kg-1.d-1; means +/- SD), threonine (147 +/- 24 vs 113 +/- 27), and histidine (124 +/- 34 vs 85 +/- 15) on urinary Zn excretion were determined in 23 newborns on TPN who received similar Zn intakes (6.8 +/- 1.4 mumol.kg-1.d-1). After a 72-h adaptation period each infant had urine collected for two 24-h periods. Despite the significant difference in amino acid intakes, mean urinary Zn excretion was identical (1.58 +/- 0.73 vs 1.56 +/- 0.63 mumol.kg-1.d-1). Hyperzincuria, therefore, does not occur when amino acids are infused at rates appropriate for the safety and nutritional maintenance of neonates.

Relationship between the sulfur content of total parenteral nutrition and sulfoester excretion in low-birthweight infants

Inorganic sulfate is an end product of sulfur amino acid metabolism but it is also the cosubstrate for the biosynthesis of a wide array of complex sulfoesters. In vitro studies have shown that SO4 availability may be the primary determinant of sulfoconjugation rates for specific substrates but the relationship between S intake and sulfoester formation in vivo is not known. By substituting MgCl2 for MgSO4 in an amino acid infusate for parenteral nutrition, we were able to examine prospectively the effect of an altered SO4 load on S metabolism. In comparing 21 low-birthweight infants on the experimental MgC2 infusate with 14 subjects on the control MgSO4 infusate, we observed a 40% decrease in urinary excretion of free SO4 and a 31% decrease in excretion of total acid-labile sulfoesters. There was a significant correlation (r = 0.44; p less than 0.02) between total S intake and sulfoester excretion, suggesting that S intake influences sulfoconjugation in the low-birthweight infant requiring total parenteral nutrition.

Effect of amino acid containing dialysis solutions on plasma amino acid profiles in children with chronic renal failure

Our previous studies demonstrated that, over single peritoneal dialysis cycles, amino acid-based dialysis solutions (AAD) were effective in dialyzing children with chronic renal failure (CRF) and offered metabolic advantages over traditional glucose dialysis solutions. The AAD, however, resulted in undesirable elevations of certain plasma amino acids, notably methionine. To further investigate the relationship between dialysate and plasma amino acid levels, we assessed the plasma amino acid response to a new AAD with relatively low methionine content (Vamin-based) over separate 5-h cycles with 1.3 and 2.3% AAD in eight patients with CRF (age 1-9 years) on continuous ambulatory peritoneal dialysis (CAPD). There was a net absorption of 70-73% of the amino acids, the net absorption of individual amino acids corresponding with the AAD composition. Plasma amino acid levels rose with AAD, peaking by 1 h postinfusion. Although most amino acids fell to preinfusion levels at the end of the cycle (including methionine), isoleucine with the 1.3% AAD and isoleucine, leucine, phenylalanine, and tyrosine with the 2.3% AAD remained significantly elevated. Having demonstrated in children that amino acids are absorbed from the peritoneal cavity in proportion to the AAD profile, modification of the current AAD is suggested.

Zinc absorption from glucose and amino acid dialysis solutions in children on continuous ambulatory peritoneal dialysis (CAPD)

Zinc deficiency in children with chronic renal failure may be due to inadequate intake or excessive losses. To determine the effect of dialysate solute type and concentration on the net absorption or loss of zinc from the peritoneal cavity, six CAPD patients ages 9-19 years were dialyzed with 1.3% and 2.3% amino acid-containing dialysis solutions and 2.5% and 4.25% glucose-containing solutions on four separate occasions. Zinc contamination of the initial effluent dialysis solutions was quite high (17.1 +/- 7.7 micrograms/dl) but did not differ between the four solutions. Significantly higher zinc retention was documented with the glucose-containing dialysis solutions compared to the amino acid-containing solutions (99.8 +/- 32.7 vs. 28.3 +/- 51.3 micrograms, 2.5% G vs 1.3% AA, p less than 0.01; 146.0 +/- 112.6 vs. 23.0 +/- 84.3, 4.25% G vs 2.3% AA, p less than .01). Although the mechanism is unclear, results of this study confirm in children that there is significant net absorption of zinc from glucose containing dialysis solutions at both high and low glucose concentrations. Thus, CAPD does not contribute to zinc depletion. Solute concentration did not affect net zinc absorption; thus it appears that movement of zinc across the peritoneum is dependent on solute type (amino acid or glucose) and independent of the osmolality.

Effectiveness and nutritional consequences of amino acid-based vs glucose-based dialysis solutions in infants and children receiving CAPD

Excessive glucose absorption and dialysate amino acid and protein losses contribute to malnutrition in children on glucose-based continuous ambulatory peritoneal dialysis (CAPD). We used 2.5 and 4.25% glucose and 1.1 and 2.0% amino acid dialysates to assess short-term effectiveness and nutritional consequences of amino acid-based dialysis solutions. Plasma and effluent urea and creatinine concentrations were similar with amino acid and glucose dialysis although 16% less fluid was removed with amino acid dialysates. Absorption of 77.3 +/- 5.3% of dialysate amino acids exceeded losses of amino acids and protein in glucose effluent. With amino acid dialysates, fasting plasma glucose concentrations were maintained while plasma amino acid levels rose, peaked at 1 h, and, excepting methionine, isoleucine, and phenylalanine with the 2.0% solution, returned to initial levels after 5 h. Compared with glucose, amino acid dialysates provide reduced but satisfactory fluid and waste removal, maintain normoglycemia, and more than compensate for effluent losses of amino acids and protein.

Percentile estimates of reference values for total protein and albumin in sera of premature infants (less than 37 weeks of gestation)

We measured the concentrations of total protein and albumin in sera of 281 well-fed premature infants, gestational ages 22-36 weeks, and calculated reference values from the 10th to 90th percentiles. The mean serum albumin concentration (27.6 +/- 4.4 g/L, mean +/- SD) and total protein concentration (49.2 +/- 6.7 g/L) at a postnatal age of 14.5 days were lower than reference values for full-term infants. We detected a significant positive correlation between albumin concentration and gestational age (r = 0.34, p less than 0.01) and total protein concentration and gestational age (r = 0.43, p less than 0.01). Even though albumin values were low, generalized edema was not present. We conclude that values for total protein and albumin in the preterm infant are lower than in the full-term infant but are an expected physiological response to premature birth.

Percentile estimates of reference values for total protein and albumin in sera of premature infants (less than 37 weeks of gestation)

We measured the concentrations of total protein and albumin in sera of 281 well-fed premature infants, gestational ages 22-36 weeks, and calculated reference values from the 10th to 90th percentiles. The mean serum albumin concentration (27.6 +/- 4.4 g/L, mean +/- SD) and total protein concentration (49.2 +/- 6.7 g/L) at a postnatal age of 14.5 days were lower than reference values for full-term infants. We detected a significant positive correlation between albumin concentration and gestational age (r = 0.34, p less than 0.01) and total protein concentration and gestational age (r = 0.43, p less than 0.01). Even though albumin values were low, generalized edema was not present. We conclude that values for total protein and albumin in the preterm infant are lower than in the full-term infant but are an expected physiological response to premature birth.

Clearance of osteocalcin by peritoneal dialysis in children with end-stage renal disease

Osteocalcin is a bone-specific protein whose concentration in blood is a direct reflection of bone turnover. In chronic renal failure, circulating osteocalcin is elevated. This elevation is due to decreased renal clearance and, in some patients, increased bone turnover secondary to renal osteodystrophy. In children receiving continuous ambulatory peritoneal dialysis, mean serum osteocalcin concentrations are substantially lower than in similar patients on hemodyalysis (1). This difference may be due to clearance of the protein by the peritoneal membrane. To test this possibility we examined osteocalcin in 16 infants and adolescents undergoing continuous ambulatory peritoneal dialysis with two commercially available glucose-based dialysis solutions (2.5 and 4.25% Dianeal). Mass transfer of osteocalcin over 5-h dialysis exchange periods was -18.9 +/- 2.8 and -28.4 +/- 7.8 micrograms for the low and high glucose solutions, respectively. Serum levels fell over the course of single exchange periods in concert with increasing dialysate concentrations. There were significant correlations between initial blood concentrations of osteocalcin and the total amount of osteocalcin transferred (r = 0.609 and 0.642 for the high and low glucose solutions, respectively, p less than 0.05). There were also strong correlations between the mass transfers of osteocalcin and those of creatinine (p less than 0.05) and total protein (p less than 0.01) with the 4.25% glucose exchange. The relationships were weaker with the 2.5% glucose exchange. Fractionation of serum revealed a single immunoreactive peak eluting coincident with intact osteocalcin, but two or three immunoreactive peaks were identified in matching dialysate samples, suggesting that both intact osteocalcin and circulating fragments are transferred by the peritoneal membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of naltrexone, an oral beta-endorphin antagonist, in children with the Prader-Willi syndrome

Children with the Prader-Willi syndrome have severe and often intractable hyperphagia unresponsive to medical or surgical treatment. Although the effect of opioid antagonists on suppressing appetite in humans has been inconsistent, we evaluated the effectiveness of a new opioid antagonist, naltrexone, in suppressing appetite in four obese adolescents with the Prader-Willi syndrome. Data were collected during the double blind oral administration of the drug and placebo for two 7-day periods. No clinical or biochemical toxicity was apparent during the naltrexone period, and measures of attention span, alertness, and mood did not change. Nutrient intake remained excessive during both the drug and placebo periods. Thus, naltrexone was ineffective in suppressing appetite, at least during the short term.

Clearance of inorganic sulfate by peritoneal dialysis in children with chronic renal failure

The peritoneal clearance of inorganic sulfate was measured in 6 infants and 12 children with end-stage renal disease who were receiving continuous ambulatory peritoneal dialysis. Serum sulfate, which was elevated before dialysis, changed little during the 5-hour dialysis period. The dialysis sulfate concentration increased at the same rate as creatinine. Net clearance of the two metabolites was not different. It was calculated that the removal by continuous ambulatory peritoneal dialysis in 24 h is comparable to the daily excretion of SO4 in healthy children.

Unconventional eating practices and their health implications

The authors discuss a number of unconventional or faddist foods and eating practices and their health implications. Among the topics included are vegetarianism, Zen macrobiotic diets, fast foods, junk foods, megavitamins and their toxicity, health foods, fad diets in infancy, and elimination diets.

Total parenteral nutrition in children

This article first focuses on the indications for total parenteral nutrition and the effect of its use on the outcome of various nutrient-depleting diseases in infants and children. This is followed by a discussion of some of the newer nutrient additions to total parenteral nutrition regimens, such as biotin, carnitine, zinc, copper, iron, and others.

Tissue selenium accretion in premature and full-term human infants and children

Development of supplementation guidelines for formulated diets and total parenteral nutrition requires knowledge of Se tissue accretion. To this end, the total organ Se content was calculated from the Se concentrations that were measured by neutron activation analysis in postmortem samples of liver (n=56), kidney (n=11), adrenal cortex (n=9), and pancreas (n=6) from infants and children from birth to 10 yr including 17 born prematurely. Hepatic Se concentrations were similar in full-term and premature newborns, decreased from birth to 1 yr, and then increased thereafter. The total hepatic Se content was significantly greater in full-term than in preterm newborns and increased with age and liver size after 1 yr. No significant differences were found between the concentrations of Se in kidney, pancreas, and adrenal tissues. Falling hepatic Se concentrations in the full-term infant concurrent with stable total organ Se content may indicate inadequate dietary intake or may reflect a normal redistribution of the nutrient. Premature infants are born with smaller stores than full-term infants and are at greater risk of developing a deficiency.

Fat overload syndrome causing respiratory insufficiency

The fat overload syndrome developed in a 7-year-old girl who was on home TPN which included 20% Intralipid (total lipid dose 3.2 g/kg/d). Acute respiratory insufficiency developed with cough, dyspnea, tachypnea, and cyanosis. The chest x-ray revealed mild cardiomegaly and pulmonary edema. Blood gases showed profound hypoxia (PaO2 29 torr on room air). Spontaneous resolution occurred over the next seven days as the lipemia cleared.

Bleeding disorder from the "fat overload" syndrome

The fat overload syndrome developed in a 7-yr-old girl receiving total parenteral nutrition with 20% Intralipid. She developed a bleeding disorder characterized by severe hematemesis that appeared to be due to abnormal platelet function associated with platelet phagocytosis of lipid demonstrable by electron microscopy. The platelet defect and bleeding reversed when the lipemia cleared.

Intravenous nitrogen intake requirements in full-term newborns undergoing surgery

To determine the intravenous intake of nitrogen needed to duplicate the weight gain and nitrogen retention observed in healthy infants fed human milk, full-term infants had weight change and nitrogen balance measured postoperatively while they were receiving two different parenteral regimens which provided adequate energy (87 kcal/kg/d) and varying intakes of nitrogen as crystalline amino acids (290 to 579 mg/kg/d) over a six-day period. Weight change was similar to that observed in breast-fed infants (35 g/d) and was independent of nitrogen intake. A significant correlation was observed between nitrogen intake and retention (r = .71, P less than .01). Substituting the rate of nitrogen retention observed in thriving full-term infants fed human milk into the regression equation describing the relationship between nitrogen intake and retention, the nitrogen intake required by parenterally fed infants in order to duplicate the accretion rate of their milk-fed counterparts was 280 mg/kg/d. After correcting for individual variation, recommended intravenous amino acid intakes range from 2.3 to 2.7 g/kg/d depending on the commercial amino acid formulation chosen and providing that adequate amounts of energy are concurrently infused.

Meeting zinc and copper intake requirements in the parenterally fed preterm and full-term infant

To determine the intravenous zinc and copper intakes required to build up body stores in the preterm infant and achieve positive retention in full-term infants, balance studies were completed in 38 preterm, full-term, and full-term SGA infants who received complete intravenously delivered nutrient formulations excluding zinc and copper. Zinc as ZnSo4 and copper as CuCl2 were then added to individual infants' formulations, with intakes ranging from 91 to 824 micrograms/kg/day (zinc) and 8 to 92 micrograms/kg/day (copper). Samples of infusate as well as urine, stool, and aspirate were collected for 72 hours and analyzed for zinc and copper by atomic absorption spectrophotometry. Zinc and copper retention correlated significantly with intake (r = 0.89; 0.82, P less than 0.01) and were independent of gestational age, postnatal age, and birth weight. In full-term and full-term SGA infants, intakes of zinc at greater than 150 and copper at greater than 16 micrograms/kg/day were adequate to replace ongoing losses and prevent acute deficiencies. The dosage for copper is similar to the current recommendation of the American Medical Association; the zinc dosage is 50% higher. Preterm infants receiving intakes of zinc at 438 and copper at 63 micrograms/kg/day achieve in utero retention rates. These dosages are significantly higher than AMA recommendations. Both combinations can be delivered by peripheral or central line without complications.

Sulfur balances in intravenously fed infants: effects of cysteine supplementation

Sulfur balances were completed in newborn infants parenterally fed with or without cysteine. In both groups, the preservative, potassium metabisulfite, accounted for the majority of sulfur intake (32 mg S/kg/day), while methionine intakes provided an additional 27 sulfate losses accounted for approximately 95% of the sulfur excretion, with the remainder contained in amino acids. Balance data accounted for over 99% of the sulfur infused in the unsupplemented group, but only 90% of that given to the cysteine-supplemented group. Thus, urinary excretion of sulfate generally reflects input from either inorganic or amino acid sources. Of the sulfur retained in the supplemented group, 75% was calculated to be retained in lean tissue and in increases in total body sulfate, but the distribution of the remaining 25% remains unknown. The failure to account fully for the sulfate provided to the cysteine-supplemented group, however, may be due to errors in the balance technique or due to an accumulation of cysteine or sulfate in body pools undefined by this study.