W. S. Dempster

An epidemiological study of well-water nitrates in a group of south west african/namibian infants

Abstract A study of 486 infants consuming well-water with various nitrate concentrations showed a strong correlation between actual nitrate intake and methaemoglobin levels. The regular administration of Vitamin C to infants is more important than the effects of age in lowering methaemoglobin levels. Mothers who live in high nitrate-bearing areas have increased infant wastage.

Red blood cell antioxidant enzyme concentrations in kwashiorkor and marasmus.

Kwashiorkor may occur when an imbalance between pro- and antioxidants in malnourished children results in an excess of free radicals. The concentrations of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GPX) were measured in erythrocytes of 22 children with kwashiorkor on admission to hospital and repeated on days 5, 10 and 30 of recovery. The concentrations were compared with those in 22 children with marasmus and in 20 children who were normally nourished but had infective illness necessitating their hospitalization. CAT and SOD were similar in all groups and did not change during recovery. GSH and GPX were significantly lower in kwashiorkor than in the other groups. Concentrations of thiobarbituric acid-reactive substances (TBARS), a marker of lipid peroxidation, were significantly elevated in children with kwashiorkor. During clinical recovery, GSH but not GPX concentrations rose despite an increase in plasma selenium levels and decreased concentrations of TBARS. These findings suggest that the antioxidant status of children with kwashiorkor differs from that of well nourished and marasmic children. Whether these differences are the cause of the consequence of the clinical picture is unresolved.

IRON FORTIFICATION OF INFANT MILK FORMULA : THE EFFECT ON IRON STATUS AND IMMUNE FUNCTION

We conducted a randomized double-blind trial of a cows milk infant formula with increased iron fortification in order to confirm its safety and to measure its effects on iron status and immune function. A group of full-term, well nourished and healthy infants was followed from the age of 3 months to 1 year. A control group of 74 infants was given a commercially available infant formula containing 8.3 mg Fe/100g. The test group of 75 infants received a similar formula with 40 mg Fe/100 g. The formula with the extra iron proved to be safe and, when compared with the control group, the children in the test group had significantly improved iron status as reflected by the proportion of children classed as normal (25 of 61 cf. 44 of 65; p less than 0.003), and by the mean values of the haemoglobin concentration (11.5 cf. 11.9 g/dl; p = 0.04), red cell distribution width (15.5% cf. 14.4%; p = 0.0005), red cell zinc protoporphyrin (3.4 cf. 4.0 micrograms/g Hb; p = 0.04) and ferritin (29 cf. 17.3 micrograms/l; p = 0.004). The extra iron fortification depressed zinc concentration in plasma (90.6 cf. 83.5 micrograms/l; p = 0.05). There was no significant difference between the two groups for laboratory measures of immune function or for incidence of infection. No adverse effects such as infection could be attributed to the increased iron. We conclude that iron fortification of cows milk infant formula may be safely increased to 40 mg/100 g (i.e. by a factor of 4.8 over the common concentration of 8.3 mg/100 g), but that this has less than the expected effect on iron status. Further studies are required to define (a) the long-term role of facilitators of iron absorption such as ascorbic acid, (b) the interaction of iron with absorption of divalent trace elements such as zinc, and (c) the effect of iron status on immune function and susceptibility to infection.

Plasma zinc, copper, selenium, ferritin and whole blood manganese concentrations in children with kwashiorkor in the acute stage and during refeeding.

Plasma zinc, copper, selenium, ferritin and whole blood manganese concentrations were measured in 22 children with kwashiorkor on admission to hospital and on days 5, 10 and 30 of refeeding. Twenty similarly aged, healthy, well nourished children served as controls. The mean (SEM) zinc, copper and selenium concentrations of 7.5 (0.93), 10.8 (0.64) and 0.29 (0.02) mumol/l, respectively, in the children with kwashiorkor on admission were all significantly lower than the values of 13.7 (0.66), 25.6 (1.72) and 0.72 (0.04) mumol/l in the controls. In contrast, the erythrocyte manganese level of 1.67 (0.09) micrograms/gHb and the median ferritin concentration of 293 micrograms/dl were significantly higher than in the controls. After 30 days there was full clinical recovery with significant weight gain and a return of the plasma albumin, caeruloplasmin, copper and ferritin to normal. However, manganese remained elevated and zinc and selenium concentrations remained significantly low. Our results suggest that nutritional rehabilitation of children with kwashiorkor is incomplete by 30 days and cannot be judged purely by a return of the plasma proteins to normal. Addition of selected trace elements to the diet may hasten full recovery.

The serodiagnosis of tuberculosis in children: an evaluation of an ELISA test using IgG antibodies to M. tuberculosis, strain H37 RV.

An enzyme-linked immunosorbent assay (ELISA) for detecting serum IgG antibodies to an autoclaved suspension of Mycobacterium tuberculosis H37 RV was evaluated as a diagnostic tool in 132 clinical cases of childhood tuberculosis. The mean (SD) optical density value in these patients was 0.115 (0.122) compared with 0.022 (0.017) in the control group of patients who had non-tuberculous acute respiratory tract infections. Using as a cut-off level the mean of the control plus 2 standard deviations, the test sensitivity was 62% and the specificity was 98% in all the patients with a clinical diagnosis of tuberculosis. In the culture-positive group (n = 35), the sensitivity was 69%. A positive correlation was shown between the optical density levels and increasing age and chronicity of infection but not with respect to tuberculin skin reactivity, nutritional status and the duration of prior therapy. In addition, BCG vaccination (presence of a scar) did not affect the ELISA result. We conclude that this ELISA test is a useful diagnostic test in children.

Diagnosis of Iron Deficiency: Mean Corpuscular Hemoglobin (MCH) as a Predictor of Iron Deficiency in Infants

Summary: Hematologic variables were measured in 240 apparently healthy infants ranging from 1–12 months of age attending a well baby clinic. There were 20 infants for each month of age. Hematologic parameters were measured in each infant by Coulter Counter Model S. Serum iron, total iron binding capacity, free erythrocyte protoporphyrin (FEP) and serum ferritin levels were measured in most infants. Their weights together with their serum iron, total iron binding capacity, and serum ferritin were judged to be independent variables of iron status, whereas the hematologic variables were considered to be response variables indicative of iron status.The correlation coefficients among these variables, after excluding redundant variables and transforming to logarithms, were computed. Canonical correlation analysis was applied to the matrix of correlation coefficients to yield the linear function of the independent variables most highly correlated with a linear function of the response variables. The linear function of the response variables was found to be well approximated by the logarithm of the mean corpuscular haemoglobin, which was highly correlated with each of the independent variables.

Search for a possible correlation between geographical area of domicile and trace element composition of human blood serum as determined by pixe

An investigation was undertaken to measure the trace elements in the blood samples by particle induced X-ray emission (PIXE). From the measured concentrations an attempt was made to group the blood specimens by pattern recognition methods as a first step in the search for a possible correlation between the geographical area of domicile and trace elemnt composition. The trend indicated that children with lower Fe and Br contents were similar in their trace element pattern, were predominantly from two district, had lower ferritin values and were breast fed longer than the remaining children in the survey.

Serum-IgE levels in rural Namibian infants

Serum IgE levels were examined in 237 infants ages 2 wk to 12 mo in a remote rural area of Namibia. There was a wide range of values (0.5 to 884 IU/ml). The highest value in the first month of life was 295 IU/ml. Median values for the age groups 2 wk to 3 mo, 3 to 6 mo, and 6 to 12 mo were higher than those reported from Western countries. Values in general increased with age, but only 4% of the variation is explicable on this basis. There were differences between median values for male and female infants, but they did not reach statistical significance at the 5% level. Levels between Baster and Nama infants, the main ethnic groups in the area, did not differ. The median IgE levels in breast-fed infants, although high, tended to be lower than those in weaned infants. The differences were not statistically significant (p greater than 0.05). Investigations did not suggest that parasitic infestations or atopy were of significant importance. It was not possible to identify the factor(s) responsible for the high IgE levels. They must have been operative from very early life. However, the basic immunologic mechanisms involved are presumably genetically determined and similar to those responsible for the corresponding high IgG, IgA, and IgM levels reported in infants from developing communities.

Serum IgG IgA and IgM levels in rural Namibian infants.

Serum IgG IgA and IgM levels were measured in 300 Baster infants and 117 Nama infants living in the Rehoboth Gebiet of Mamibia. The serum immunoglobulin levels were much higher than those of infants living in developed countries. This agrees with findings in infants or children of other developing communities. Differences in the mean levels of IgA and IgM appeared to be related to age sex and ethnicity. These differences even though of statistical significance are not large enough to influence the practising physician in his interpretation of laboratory results in Namibian infants. The mean standard deviation and ranges of immunoglobulin IgG IgA and IgM levels of Baster and Nama infants may be used as reference values for infants living in the Rehoboth Gebiet. It was not possible to relate the immunoglobulin findings and their accelerated production compared to those of infants in North America and Scandinavia with any of the variables studied including age sex ethnicity feeding pattern habitat environment of serum methemoglobin and ascorbic acid levels. These and other factors presumably all interact in some way on an immunological system which is genetically coded to provide the fetus neonate infant and child with support for healthy survival under adverse environmental conditions. (authors)

Ferritin levels in human milk

Ferritin was detected and quantitated in breast milk from 24 mothers of healthy fullterm infants 3 days, 7 days, 6 weeks and 3 months after delivery. Highest concentrations were found at day 3 and demonstrated a marked decline at day 7, with negligible levels at 6 weeks and 3 months. The values in breast milk were compared with mothers serum ferritin concentration at delivery and a significant but weak correlation (r = 0.475, P less than 0.05) was found between the paired values of maternal serum ferritin at delivery and breast milk ferritin at day 3. The possible biological significance of ferritin in breast milk is discussed.