The determination of zinc in blood plasma by atomic absorption spectrometry

Study protocol for a zinc intervention in the elderly for prevention of pneumonia, a randomized, placebo-controlled, double-blind clinical pilot trial

Pneumonia is a major public health problem for older adults, being one of the leading causes of hospitalization and death, particularly for elderly nursing home residents. We previously conducted a clinical trial in which we demonstrated that 29% of nursing home residents had low serum zinc levels coinciding with a two-fold increase in pneumonia incidence and duration in comparison to individuals with adequate serum zinc levels. However, causality could not be inferred and necessitates a double-blind clinical trial. To determine the appropriate supplementation dose for such a trial we are conducting a randomized, placebo-controlled, double-blind clinical pilot trial aimed at delineating the optimal dosage (30 and 60 mg/day elemental Zn) and establishing safety. The results from the pilot study will be leveraged to inform our larger randomized clinical trial designed to study the effect of zinc supplementation in nursing home elderly with low serum zinc levels on respiratory infections, antibiotic use, and duration of sick days with pneumonia. In tandem with dose optimization, we will evaluate the correlation between serum zinc and pan-T cell zinc levels, given that T cells and their zinc levels are important in the response and resolution of respiratory infections but whose correlation has only been extrapolated and not demonstrated. Herein we present the study rationale and protocol, as well as discuss specific challenges we encountered in securing a manufacturer for the study agents and when recruiting from nursing home populations during the COVID-19 pandemic. In light of these experiences, we provide recommendations for future clinical trials under circumstances where supply chains are disrupted, and recruitment pools are constrained or unavailable.

Clinical trial registration

https://clinicaltrials.gov/, NCT05527899.

Associations between maternal plasma zinc concentrations in late pregnancy and LINE-1 and Alu methylation loci in the young adult offspring

BACKGROUND

In animal models, prenatal zinc deficiency induced epigenetic changes in the fetus, but data in humans are lacking. We aimed to examine associations between maternal zinc levels during pregnancy and DNA methylation in LINE-1 and Alu repetitive sequences in young adult offspring, as well as anthropometry and cardiometabolic parameters.

METHODS

Participants were 74 pregnant women from the Chiang Mai Low Birth Weight cohort, and their offspring followed up at 20 years of age. Maternal plasma zinc concentrations were measured at approximately 36 weeks of gestation. DNA methylation levels in LINE-1 and Alu repetitive sequences were measured in the offspring, as well as anthropometry and cardiometabolic parameters (lipid profile, blood pressure, and glucose metabolism).

RESULTS

Over half of mothers (39/74; 53%) were zinc deficient (<50 μg/dL) during their third trimester of pregnancy. Maternal zinc concentrations during pregnancy were associated with LINE-1 DNA methylation levels in adult offspring. Specifically, lower prenatal zinc concentrations were associated with: 1) lower levels of total LINE-1 methylation; 2) lower levels of LINE-1 hypermethylation loci; and 3) higher levels of LINE-1 partial methylation loci. Prenatal zinc concentrations were not associated with Alu methylation levels, nor with any anthropometric or cardiometabolic parameters in adult offspring. However, we observed associations between Alu and LINE-1 methylation patterns and cardiometabolic outcomes in offspring, namely total cholesterol levels and diastolic blood pressure, respectively.

CONCLUSIONS

Lower maternal zinc concentrations late in gestation were associated with changes in DNA methylation in later life. Thus, zinc deficiency during pregnancy may induce alterations in total LINE-1 methylation and LINE-1 hypermethylation loci. These results suggest a possible epigenetic link between zinc deficiency during pregnancy and long-term outcomes in the offspring.

Incidence and prevalence of copper deficiency following roux-en-y gastric bypass surgery

INTRODUCTION AND OBJECTIVES

The frequency of copper deficiency and clinical manifestations following roux-en-y gastric bypass (RYGB) surgery is not yet clear. Objectives were to determine the prevalence and incidence of copper deficiency in patients who have undergone RYGB.

DESIGN AND METHODS

We sought to determine the number of RYGB patients undergoing medical and nutritional follow-up visits at the Emory Bariatric Center who experienced copper deficiency and associated hematological and neurological complaints (n=136). Separately, in patients followed longitudinally before and during 6 and 24 months following RYGB surgery, we obtained measures of copper status (n=16). Systemic blood cell counts and measures of copper, zinc and ceruloplasmin were determined using standardized assays in reference laboratories including atomic absorption spectrometry and immunoassays.

RESULTS

Thirteen patients were identified to have copper deficiency suggesting a prevalence of copper deficiency of 9.6%, and the majority of these had concomitant complications including anemia, leukopenia and various neuro-muscular abnormalities. In the longitudinal study, plasma copper concentrations and ceruloplasmin activity decreased over 6 and 24 months following surgery, respectively (P<0.05), but plasma zinc concentrations did not change. A simultaneous decrease in white blood cells was observed (P<0.05). The incidence of copper deficiency in these subjects was determined to be 18.8%.

CONCLUSIONS

The prevalence and incidence of copper deficiency following RYGB surgery was determined to be 9.6% and 18.8%, respectively, with many patients experiencing mild-to-moderate symptoms. Given that copper deficiency can lead to serious and irreversible complications if untreated, frequent monitoring of the copper status of RYGB patients is warranted.

Red meat and a fortified manufactured toddler milk drink increase dietary zinc intakes without affecting zinc status of New Zealand toddlers

Evidence suggests that New Zealand (NZ) children are mildly zinc deficient and may respond to dietary change. A 20-wk randomized intervention trial was therefore conducted to determine whether an increased intake of red meat or consumption of a fortified manufactured toddler milk drink (FTMD, fortified with zinc and other micronutrients) would increase dietary zinc intakes and improve the biochemical zinc status of 12- to 20-mo-old NZ toddlers. Toddlers were randomized to a red meat intervention (n = 90), FTMD intervention (n = 45), or nonfortified milk placebo (n = 90). Study foods were provided. Adherence was assessed via monthly 7-d meat or milk recording diaries. Hair and serum zinc concentrations, and length and weight were measured at baseline and postintervention. Nutrient intakes were assessed via 3-d weighed food records at baseline, wk 4, and wk 18. At baseline, 38% of participants had low serum zinc concentrations despite seemingly adequate dietary zinc intakes (<4% below the Estimated Average Requirement). Dietary zinc intakes significantly increased by 0.8 mg/d (95% CI: 0.5, 1.1) in the meat group and 0.7 mg/d (95% CI: 0.2, 1.1) in the FTMD group compared with a decrease of -0.5 (95% CI: -0.8, -0.2) mg/d in the placebo group. No corresponding increases in serum or hair zinc concentrations were observed. Dietary zinc intakes achievable via interventions based on red meat or a FTMD are unlikely to improve biochemical zinc status in NZ toddlers. These results also question cutoffs used to define zinc deficiency in toddlers.

High incidence of zinc deficiency among Filipino children with compensated and decompensated liver disease

BACKGROUND AND AIM

The role of zinc in the nutrition and growth of children with chronic liver disease is poorly defined. The present study determined the serum zinc levels of children with compensated liver disease (CLD) and decompensated liver disease (DLD) and compared this with healthy children. Zinc levels were also correlated with the severity of liver disease as measured by Child-Pugh scores.

METHODS

The study comprised of 60 children 0-10 years of age with chronic liver disease, defined as CLD (n = 30) if the Child-Pugh score was < 6, and DLD (n = 30) if the Child-Pugh score was > or = 6. Thirty healthy children 0-10 years served as controls. Serum zinc levels were measured by atomic absorption spectrometry.

RESULTS

The 90 patients included 30 with CLD (mean age: 4.54 years: 21 boys; mean Child-Pugh score: 5.83), 30 with DLD (mean age: 1.39 years; 17 boys; mean Child-Pugh score: 9.53) and 30 healthy children (mean age: 4.6; 16 boys). Zinc levels of patients with CLD were significantly lower compared with the healthy controls (Mean [standard deviation]: 68.07 [31.55]vs 89.9 [25.9]microg/dL, P = 0.000), but significantly higher compared to the patients with DLD (48.8 [26.8]microg/dL). Correlation studies showed that the higher the Child-Pugh score, the lower the zinc levels (r = -0.460)

CONCLUSIONS

Children with chronic liver disease, whether in a compensated or decompensated state, had lower serum zinc levels compared with the healthy controls. As the severity of liver disease worsened, the zinc levels decreased. The study suggests that zinc supplementation should constitute part of the micronutrient intake of children with chronic liver disease.

Chelation of GRP78 with lead and its localization changes in the astroglia of rats exposed to lead

To observe the chelation of GRP78 with lead (Pb) and its localization changes, astroglial cells from Wistar rat brain were primarily cultured in medium with acetate Pb. The processes were terminated at different time points. The immunoprecipitation (IP) and Western blotting were used for GRP78 purification and expression and the Pb concentration was determined by employing atomic absorption spectrophotometry (AAS). The localization change of GRP78 was observed with colloid gold immunoelectron microscopy. The results showed that the expression of GRP78 was increased significantly in the cells treated with 1.0 micromol/L acetate Pb for 24 h and peaked at 96-192 h (P<0.01), and at the 12th day, the expression of GRP78 began to decrease but was still higher than normal (P<0.05). Pb content started to increase when cells were treated by acetate Pb for 24 h, and the peak appeared at 8 day (P<0.01), and then Pb content decreased gradually, but was still higher than normal (P<0.05). GRP78 protein expression began to remarkably increase when it transferred from ER to the cytosol around the nuclei 24 h after treatment with Pb. It is concluded that GRP78 in astroglia could strongly chelate with Pb ions and it might be a target protein of Pb.

Superoxide dismutase, copper and zinc concentrations in platelet-rich plasma of pneumonia patients

BACKGROUND

The aim of this study was to analyse platelet superoxide dismutase (SOD) activities (total SOD, manganese SOD and copper zinc SOD) and copper (Cu) and zinc (Zn) concentrations during the course of community-acquired pneumonia (CAP), and to compare them between patients with normal platelet count and those who have developed reactive thrombocytosis (RT).

METHODS

Platelet count, SOD activities and Cu and Zn concentrations in platelet-rich plasma were measured in patients with CAP on admission and at discharge.

RESULTS

Post-therapeutic platelet count increased significantly from the value recorded on admission. By the end of treatment, 42% of patients developed RT. All platelet SOD activities as well as Cu concentration were significantly lower in CAP patients than in control subjects. The initial Zn concentration was greater in CAP patients compared with controls and showed a decrease at discharge. On admission, there was no difference in all SOD activities between either subgroup with normal platelet count or subgroup with RT. At discharge all SOD activities were significantly lower in patients with RT. Also, catalytic activities of those enzymes were significantly lower in both subgroups in comparison with the initial values. Post-therapeutic Cu value was lower in patients with RT in comparison with patients having normal platelet count. Zn concentration decreased significantly at discharge when compared with the initial values only in patients with RT.

CONCLUSION

The pattern of changes might be indicative of a certain role of platelets in antioxidant response during treatment in CAP patients.

Impact of zinc supplementation in children with acute diarrhoea in Turkey

OBJECTIVE

Zinc deficiency is prevalent in children in developing countries. Supplemental zinc provides therapeutic benefits in diarrhoea. Our aim was to evaluate the effect of daily zinc supplementation for 14 days on diarrhoea duration, severity, and morbidity in children.

METHODS

In a randomised, open label non-placebo controlled trial, we assessed the efficacy of providing zinc sulfate to 6-60 month old children with acute diarrhoea for 2 weeks followed by 3 months of morbidity surveillance. Children were randomly assigned to zinc (n = 150) and control (n = 130) groups and received 15-30 mg elemental zinc daily.

RESULTS

Supplemented children had significantly improved plasma zinc levels by day 14 of therapy. Zinc deficiency was observed in 2.6% of the treatment and 3.3% of the control group. The mean duration of diarrhoea after starting supplementation was 3.02+/-2 days in the zinc group and 3.67+/-3.2 days in the control group. There was no significant difference in diarrhoea duration by treatment group (p>0.05). The number of stools after starting supplementation was 5.8+/-3.7 and 5.1+/-3.9 on day 1, 2.9+/-1.6 and 3.0+/-2.2 on day 2, and 1.8+/-1.1 and 1.6+/-0.9 on day 3 in the zinc and control groups, respectively. There was no significant difference in diarrhoea severity by treatment group (p>0.05). No significant effect was found on the incidence and prevalence of diarrhoea in the zinc compared with the control group.

CONCLUSION

Our data indicate that supplementing children with acute diarrhoea in Turkey with 3 RDA of elemental zinc for 14 days improved neither diarrhoea duration nor severity despite significant increments in plasma zinc.

Effect of zinc replacement on lipids and lipoproteins in type 2-diabetic patients

Abnormal zinc and lipid plasma levels occur more frequently in metabolically uncontrolled diabetic patients. These lipid alterations are key factors in the emergence of microvascular complications, which lead to death in those patients. Yet, zinc sulfate supplementation may be a therapeutical resource to recover some functioning and improve life span. This article reports the assessment of lipid profile from type 2-diabetes mellitus patients treated with hypoglycemic therapy drugs, who additionally presented zinc levels lower than average in Mexican reference. The patients received a 100 mg zinc sulfate treatment in a crossover double-blind design of clinically controlled study with starch as placebo. The diabetic patients had changes in their lipid profile after a 12-week zinc treatment as compared with placebo treatment. The 100 mg zinc sulfate treatment was well tolerated, significantly reduced total cholesterol and triglyceride concentrations, and increased those corresponding to zinc as well as HDL cholesterol in the bloodstream. Thus, using this treatment the cardiovascular involvement is expected to decrease in the type 2-diabetes mellitus patients, especially those with myocardial infarction and stroke, which are the main death causes in Mexico.

Exclusive breast-feeding for 6 months, with iron supplementation, maintains adequate micronutrient status among term, low-birthweight, breast-fed infants in Honduras

There is little information on the risk of micronutrient deficiencies during the period of exclusive breast-feeding. We evaluated this among term, low-birthweight (LBW; 1500-2500 g) infants in Honduras. Mother-infant pairs were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo. At 4 mo, infants were randomly assigned to either continue exclusive breast-feeding to 6 mo (EBF; n = 59) or be given iron-fortified complementary foods (rice, chicken, fruits, and vegetables) from 4 to 6 mo while continuing to breast-feed (SF, n = 60). Blood samples were collected at 2, 4, and 6 mo and analyzed for hemoglobin (Hb), hematocrit, plasma ferritin, % transferrin saturation, vitamin A, vitamin B-12, folate, zinc, and erythrocyte folate. Infants with Hb < 100 g/L at 2 or 4 mo were given medicinal iron supplements for 2 mo; the proportion administered iron drops did not differ significantly between groups. There was no significant effect of complementary foods on indices of vitamin A, B-12, folate, or zinc status. Among infants not given medicinal iron at 4-6 mo, iron status was higher in the SF group than the EBF group. In those given medicinal iron at 4-6 mo, iron status was higher in the EBF group, suggesting that complementary foods interfered with iron utilization. About half of the infants were anemic by 2 mo, before the age when complementary foods would be recommended. This supports the recommendation that LBW infants should receive iron supplementation in early infancy. Given that infants given iron supplements did not benefit from complementary foods at 4-6 mo, we conclude that exclusive breast-feeding for 6 mo (with iron supplementation) can be recommended for term, LBW infants.

Serum levels of antioxidant vitamins, copper, zinc and magnesium in children with chronic rhinosinusitis

Reactive oxygen species including hydroxyl radicals, superoxide anions and hydrogen peroxide which are produced by activated granulocytes play an essential role in many biochemical processes and diseases. Oxidant-mediated tissue damage may be important in the development of chronic sinusitis. The aim of this study was to investigate the serum levels of antioxidant vitamins and elements in 24 children (14 boys and 10 girls, age range: 7-12 years, mean age: 9.2 years) with chronic rhinosinusitis, compared to 20 age and sex matched healthy children. Blood samples were collected in the morning before breakfast and prior to any medication. Vitamin A, E and C levels were determined using reagent kits for high performance liquid chromatography. Cu, Zn and Mg levels were analyzed by atomic absorption spectrometry. Vitamin E, vitamin C, Cu and Zn levels were significantly lower in the patients group than in the control group. However, vitamin A and Mg levels did not differ. In conclusion, serum levels of antioxidant vitamins and elements may be important in the pathogenesis and treatment of chronic rhinosinusitis in children.

An evaluation of the influence of therapeutic interventions on serum trace element levels in groups of patients

The aim of the study was to propose a method of large amount data evaluation. A new graphical method for data evaluation was suggested: the data were ranked according to the initial values and both the initial values and final values were intersected by polynomial curves. This method was used in the following situations: 1. Serum levels of Mg and Zn were measured just before and after hemodialysis (HD) in 87 patients in chronic renal failure. 2. Mg levels in serum, red blood cells and urine were estimated in 20 patients before and after administration of a Mg containing drug. Three basic graphic forms of curves were established: 1. Significant decrease of serum Mg levels during HD resulted in two uncrossed lines, the initial-values line being higher than terminal-values one (the higher the initial level the more pronounced was its decrease during HD). 2. Balanced effect of HD on the serum levels of Zn (low values increased, high levels decreased) represented two crossing-lines. 3. Significant increase of urine Mg in patients supplemented by Mg demonstrated two uncrossed lines. The position of initial-values curve was lower than the terminal-values one. The proposed graphical method of the evaluation of large amounts of data is simple and enables a quick orientation in the assessment of the effects of therapeutic interventions (trace elements, drugs and other relevant substances).

Can zinc deficiency be used as a marker for the diagnosis of celiac disease in Turkish children with short stature?

BACKGROUND

It is generally accepted that celiac disease (CD) must always be considered when dealing with growth failure in children. Therefore, it is important to develop screening tests for detecting patients that need an intestinal biopsy. The aim of the present study was to investigate the value of plasma zinc levels for the diagnosis of monosymptomatic CD in short-statured children.

METHODS

Fourty-nine children with a short stature and 34 healthy controls were investigated. Plasma zinc levels were assayed by atomic absorption spectrophotometry in short-statured children and controls. All patients with short stature underwent endoscopic small intestinal biopsy.

RESULTS

Duodenal mucosal histopathology was normal in 25 children. Low plasma zinc values were observed in 54.2% of patients with CD, 32.0% of patients with idiopathic short stature and 14.8% of controls. The mean values of plasma zinc levels were not significantly different among the three groups. Sensitivity, specificity and the positive and negative predictive values for plasma zinc were 45.8, 76.0, 64.7 and 59.4%, respectively.

CONCLUSIONS

These results indicate that zinc deficiency is an important problem in CD children with short stature; however, plasma zinc levels are not useful as a screening test for selecting patients for jejunal biopsy.

The metabolic availability of vitamin A is decreased at the onset of diabetes in BB rats

Streptozotocin (STZ)-induced diabetic rats have been associated with an impaired metabolic availability of vitamin A (retinol). This study was undertaken to investigate whether Biobreeding (BB) rats, in which diabetes mellitus resembling human type I diabetes develops spontaneously, respond the same way at the onset of diabetes. Weaning diabetes-prone (BBdp) and normal (BBn) BB rats consumed NIH-07 nonpurified diet ad libitum until 120 d of age. Plasma and hepatic concentrations of retinol and its carriers, retinol-binding protein (RBP) and transthyretin (TTR) were lower in diabetic BB (BBd) rats than in BBn rats. In parallel with RBP, the abundance of mRNA was lower in the liver of BBd rats. Furthermore, the status of zinc, an important factor for the synthesis of RBP, was also disturbed in BBd rats, as indicated by lower circulatory levels and greater urinary excretion. To determine whether the biochemical evidence of vitamin A deficiency in BBd rats could be reversed, BBdp rats were fed a diet supplemented with vitamin A either alone or in combination with zinc. None of these treatments increased plasma vitamin A concentration. The hepatic abundance of RBP mRNA was significantly greater, whereas circulatory RBP concentrations were unaffected by vitamin A plus zinc supplementation. Overall, these results suggest that impaired metabolic availability of vitamin A, possibly caused by its decreased transport from hepatic stores, is another metabolic derangement associated with type I diabetes.

Zinc supplementation and stunted infants in Ethiopia: a randomised controlled trial

BACKGROUND

Stunting is highly prevalent in Ethiopia and many other developing countries but the reason for it is poorly understood. Zinc is essential for growth but diets in such countries often do not contain zinc in sufficient quantity or of sufficient bioavailability. Thus zinc deficiency may play a major role in stunting. The aim of the study was to investigate whether the low rate of linear growth of apparently healthy breastfed infants in a rural village in Ethiopia could be improved by zinc supplementation.

METHODS

A randomised, double-blind, placebo-controlled trial was done on apparently healthy breastfed infants aged 6-12 months. 100 non-stunted (length-for-age, Z score < -2) were matched for age and sex with 100 randomly selected stunted (> -2) infants. Infants, both stunted and non stunted, were matched by sex, age (within 2 months) and recumbent length (within 3 cm) for random assignment, to receive a zinc supplement (10 mg zinc per day, as zinc sulphate) or placebo, 6 days a week for 6 months. Anthropometric measurements were taken monthly, data on illness and appetite were collected daily, and samples of serum and hair were taken at the end of the intervention for the analysis of zinc.

FINDINGS

The length of stunted infants increased significantly more (p<0.001) when supplemented with zinc (7.0 cm [SE 1.1]) than with placebo (2.8 cm [0.9]); and the effect was greater (p<0.01) than in non-stunted infants (6.6 [0.9] vs 5.0 [0.8] cm for the zinc and placebo groups respectively, p<0.01). Zinc supplementation also increased the weight of stunted children (1.73 [0.39] vs 0.95 [0.39] kg for the corresponding placebo group, p<0.001) and of non-stunted children (1.19 [0.39] vs 1.02 [0.32] kg for the corresponding placebo group, p<0.05). Zinc supplementation resulted in a markedly lower incidence of anorexia and morbidity from cough, diarrhoea, fever, and vomiting in the stunted children. The total number of these conditions per child was 1.56 and 1.11 in the stunted and non-stunted zinc supplemented children versus 3.38 and 1.64 in the stunted and non-stunted placebo-treated children, respectively. At the end of the intervention period, the concentrations of zinc in serum and hair of stunted infants, who had not been supplemented with zinc, were lower than the respective concentrations of zinc in serum and hair of their non-stunted counterparts.

INTERPRETATION

Combating zinc deficiency can increase the growth rate of stunted children to that of non-stunted infants in rural Ethiopia. This would appear to be due, at least in part, to reduction in morbidity from infection and increased appetite.

Predictors of micronutrient status among six- to twelve-month-old breast-fed Ghanaian infants

This study describes the factors associated with hemoglobin and plasma ferritin, zinc and retinol concentrations and erythrocyte riboflavin status among 208 Ghanaian infants who participated in a complementary feeding intervention trial from 6 to 12 mo of age. Anthropometric, morbidity and dietary data were collected regularly from 1 to 12 mo; blood samples were collected at 6 and 12 mo. The prevalence of low micronutrient status at 6 and 12 mo, respectively, was as follows: hemoglobin <100 g/L, 30 and 34%; plasma ferritin <12 microg/L, 17 and 43%; plasma zinc <10.7 micromol/L, 4 and 6%; plasma retinol <0.7 micromol/L, 26 and 26%; erythrocyte riboflavin <200 umol/L of packed red cells, 14 and 10%. Multiple regression was used to identify factors significantly associated with micronutrient status. From 6 to 12 mo, fever prevalence was associated with a decrease in hemoglobin, but an increase in erythrocyte riboflavin concentrations, and diarrhea prevalence was related to a decrease in plasma retinol. Seasonal differences were evident for most of the indicators of micronutrient status, and elevated C-reactive protein levels (indicative of recent infection) were related to lower hemoglobin, retinol and zinc concentrations but higher ferritin and erythrocyte riboflavin concentrations. Weight at birth or at 1 mo of age was positively related to iron, zinc and vitamin A status, but a more rapid weight gain was associated with depletion of iron stores. Socioeconomic status was related to higher hemoglobin, riboflavin and zinc concentrations. The feeding of a micronutrient-fortified food was positively associated with plasma ferritin and retinol concentrations at 12 mo. These results suggest that prenatal factors, socioeconomic status, dietary intake and morbidity all influence infant micronutrient status, and that fortification of complementary foods is one potential avenue for preventing deficiencies.

A randomized, community-based trial of the effects of improved, centrally processed complementary foods on growth and micronutrient status of Ghanaian infants from 6 to 12 mo of age

BACKGROUND

Koko, a fermented maize porridge used as the primary complementary food in Ghana, has been implicated in the high prevalence of child malnutrition. Weanimix, a cereal-legume blend developed by the United Nations Children's Fund and the Ghanaian government, has been promoted as an alternative.

OBJECTIVE

We evaluated the effect of feeding Weanimix and 3 other locally formulated, centrally processed complementary foods on the nutritional status of 208 breast-fed infants.

DESIGN

Infants were randomly assigned to receive 1 of 4 foods from 6 to 12 mo of age: Weanimix (W), Weanimix plus vitamins and minerals (WM), Weanimix plus fish powder (WF), and koko plus fish powder (KF). Dietary and anthropometric data were collected regularly. Blood was collected at 6 and 12 mo of age to assess iron, zinc, vitamin A, and riboflavin status. Before and after the intervention, cross-sectional data on the anthropometric status of infants not included in the intervention (NI; n = 464) were collected.

RESULTS

There were no significant differences between intervention groups in weight or length gain or in hemoglobin, hematocrit, transferrin saturation, plasma zinc, or erythrocyte riboflavin values between 6 and 12 mo of age. From 9 to 12 mo of age, z scores were lower in NI infants than in the combined intervention groups [at 12 mo: -1.71 +/- 0.90 compared with -1.19 +/- 0.93 for weight and -1.27 +/- 1.02 compared with -0.63 +/- 0.84 for length (P < 0.001 for both), respectively]. The percentage of infants with low ferritin values increased significantly between 6 and 12 mo of age in groups W, WF, and KF but not in group WM. Change in plasma retinol between 6 and 12 mo of age was significantly greater in group WM than in the other 3 groups combined (0.14 +/- 0.3 compared with -0.04 +/- 0.3 micromol/L, P = 0. 003).

CONCLUSIONS

All 4 foods improved growth relative to the NI group. Infants fed WM had better iron stores and vitamin A status than those fed nonfortified foods.

Serum and hair zinc levels in epileptic children taking valproic acid

This study was performed to investigate the serum and hair zinc levels in patients epilepsy diagnoses who were intended to be put on valproic acid (VA) monotherapy and had never ingested antiepileptics before. A total of 16 patients having normal growth, development and nutrition was selected as Group 1, and Group 2 was made up of 10 patients who had received VA monotherapy for 2 yrs or more and had normal growth, development, and nutrition characteristics. A control group (Group 3) was formed of 15 subjects who applied to the hospital for upper respiratory tract disorders. Serum and hair samples were taken for zinc assays from the Group 1 patients on the d 0, 15, 30, 45, 60, 75, and 180. Groups 2 and 3 were sampled only once, and zinc levels were determined. We found that both serum and hair zinc levels in Group 1 were higher than those of Group 2 and control group before the beginning of VA therapy, but they returned to normal during VA treatment. There was no zinc deficiency, and zinc replacement treatment may therefore be considered as unnecessary.

Zinc as a cofactor for heparin neutralization by histidine-rich glycoprotein

We have studied the ability of histidine-rich glycoprotein (HRG) to neutralize the anticoagulant activity of heparin in plasma and in a purified component clotting assay. Addition of HRG to plasma or to the purified component assay did not neutralize the anticoagulant activity of heparin unless micromolar concentrations of zinc were present. Higher zinc concentrations were required for citrated than for heparinized plasmas due to competition of citrate with HRG for zinc binding. Zinc concentrations as low as 1.25 microM revealed HRG to be a powerful competitor of antithrombin for heparin in the purified component assays. HRG binding of heparin also was shown by affinity chromatography of HRG from immobilized heparin in the presence and absence of zinc. In the absence of zinc, HRG was eluted by 0.1 M NaCl, but, in the presence of zinc, elution of HRG required 1.0 M NaCl. Investigation of other divalent cations (copper and magnesium) indicated that augmentation of heparin binding by HRG in the presence of antithrombin was restricted to zinc. The HRG.Zn complex effectively competes with antithrombin for heparin, which restricts the availability of heparin to bind antithrombin and allows thrombin-mediated fibrinogenesis to proceed unimpeded. This could be initiated by zinc released from activated platelets.

Serum haptoglobin as an indicator of the acute phase response in bovine respiratory disease

The early stages of the host response to infectious agents include a number of physiologic changes, collectively known as the acute phase response. The acute phase response is comprised of reactions localized at the site of infection, as well as the initiation of systemic responses, which include a rapid increase in the serum concentration of some proteins, known as acute phase proteins (APP). Using polyacrylamide gel electrophoresis, we detected two APP of approximately 22 and 37 kDa molecular weight in sera obtained from cattle with bovine respiratory disease (BRD). Based on their presence in the sera of sick, but not normal animals, the molecular weights, N-terminal amino acid sequence analysis, and the ability to bind hemoglobin, we identified these proteins as the alpha and beta subunits of haptoglobin. The haptoglobin molecule and the alpha subunit were isolated from serum, purified, and used to produce monoclonal and polyclonal antibodies. With these reagents, an enzyme linked immunosorbent assay was developed to measure the concentration of haptoglobin in bovine serum. Using an experimental model of BRD induced by a sequential challenge of calves with bovine herpesvirus type-1 and Pasteurella haemolytica, we observed a temporal relationship between the increase in haptoglobin concentration in serum and the onset of bacterial infection. The haptoglobin concentration ranged from undetectable in the serum of most calves prior to challenge, to greater than 1 mg ml(-1) in over one-third of the calves at the height of disease. Furthermore, the concentration of haptoglobin was associated significantly with other measures of the severity of disease. Together, these results indicate that quantification of acute phase proteins in animals with BRD could be a valuable diagnostic and prognostic aid.

Serum levels of zinc and copper in patients with Parkinson's disease

Several recent studies have shown decreased copper and increased zinc concentrations in the substantia nigra and increased copper concentrations in the cerebrospinal fluid of Parkinson's disease patients. To elucidate whether changes in serum levels of these trace elements may increase the risk of developing Parkinson's disease (PD), we assessed serum levels of zinc and copper by flame atomic absorption spectrophotometry, and albumin and ceruloplasmin, in 32 (Zn) and 39 PD patients (Cu), respectively, with their spouses as the control group. Serum zinc, albumin, copper and ceruloplasmin levels and the zinc/albumin and copper/ceruloplasmin ratios, did not differ significantly between the two groups and were not influenced by antiparkinsonian therapy in the PD patients. Serum zinc/albumin ratio (r = 0.43), ceruloplasmin (r = -0.36) and copper/ceruloplasmin ratio (r = 0.36) correlated significantly with age, but not with age of onset, duration of the disease, scores of the Unified Parkinson's Disease Rating Scale and Hoehn and Yahr staging in PD patients. These values did not correlate with age in the control group. These results suggest that serum levels of zinc and copper do not play any role as risk factors for PD.

Trace element determination in humans. The use of blood and hair

With the present study, we intend to verify the utility of hair as diagnostic tool for trace element analysis, to substitute, perhaps, conventional materials, such as blood serum. Blood and hair were collected from male individuals (n = 107) aged 20-59 y. Determinations of Cu and Zn concentrations were performed with atomic absorption spectrometry. An influence of age on Zn in hair has been found, with significantly different values before and after age 30 y. There is no correlation between Cu concentrations in hair and in serum, and a positive one (r = 0.3554, p < 0.05) between Zn levels in hair and in serum. No association between Zn and Cu levels in hair has been demonstrated; on the contrary, these elements have a moderate positive correlation in serum (r = 0.3586, p < 0.01). The data indicate that hair may represent an additional analytical material for Cu and Zn to complement blood serum.

Effect of a single oral dose of ascorbic acid on body temperature and trace mineral fluxes in healthy men and women

Several metabolic changes characteristic of the acute-phase response were examined in healthy men and women following a single 1 g dose of ascorbic acid. Utilizing a placebo-controlled, double-blind protocol, oral body temperatures were recorded in rested, fasted subjects (0900 hr) prior to the consumption of 1 g L-ascorbic acid or placebo (n = 10/group). Temperatures were recorded hourly for the next 8 hours, and again the next morning in the rested, fasted state (0900 hr). Blood samples, collected at 0, 4, and 24 hours post-dose, were analyzed for plasma ascorbate, iron, and zinc. Mean oral body temperature was significantly elevated 2 hours post-dose in the experimental subjects compared to controls (+0.7 degrees F, p = 0.03). In the vitamin-dosed subjects, mean plasma ascorbate rose 32% over the control value after 4 hours (1.11 +/- 0.08 and 0.84 +/- 0.06 mg/100 ml, ns). Serum iron levels were similar in the two groups at 0 and 4 hours post-dose, but at 24 hours post-dose mean serum iron of the vitamin-dosed subjects fell to 73% of that recorded for the control subjects (77 +/- 8 and 105 +/- 10 micrograms/100 ml, p = 0.04). Plasma zinc levels were similar for both groups at 0, 4, and 24 hours post-dose. These data indicate that ascorbate administration, at a level commonly supplemented in the US diet, elicits several host metabolic responses similar to those observed following exposure to infectious or inflammatory agents. These metabolic changes are most likely due to the reducing potential of the vitamin and may factor in the reported prophylactic success of vitamin C supplementation.

Opening the blood-brain barrier to zinc

Sheep with guide tubes implanted over the brain lateral ventricles, in order to facilitate episodic sampling of cerebrospinal fluid (CSF), were used to determine the effects of increasing cranial blood osmolality or electroconvulsive shock (ECS) on the permeability of the blood-brain barrier (BBB) to zinc. Zinc acetate solution (1 mg Zn/ml) was infused intravenously (i.v.) at 1.0 ml/min for 30 min and then continuously at 0.125 ml/min. This infusion increased plasma total zinc concentration (pZn) approximately 10-fold without altering CSF zinc concentration (CSFZn). After 1.5-3.5 h, 4 M NaCl was infused at 5-10 ml/min for 10 min into one carotid artery with the other carotid artery occluded, or the animals were anaesthetized and given an ECS (140 V, 2 s). Paired samples of blood and CSF were collected before and after these treatments. Results were: (i) CSFZn was approximately one tenth of pZn; (ii) zinc administered i.v. was almost completely excluded from the CSF; (iii) increased cranial blood osmolality or ECS increased CSFZn in all experiments, but the time course and extent of the rise were variable. CSFZn reached the concentrations of zinc in normal sheep plasma in some experiments; (iv) CSFZn subsequently fell towards the low values of zinc in normal CSF; (v) the animals suffered no evident ill-effects from either procedure. The procedures may, therefore, be used for reversible opening of the BBB to particles such as zinc in conscious or anaesthetized sheep with no troublesome sequelae.

2',5' oligoadenylate synthetase activity in bovine peripheral blood mononuclear cells following bovine herpesvirus type-1-induced respiratory disease: a prognostic indicator?

Following aerosol-challenge of nonimmune calves with bovine herpesvirus type-1 (BHV-1) the levels of 2',5' oligoadenylate (2-5A) synthetase in peripheral blood mononuclear cells (PBML) increased significantly to peak 4-5 days after BHV-1 infection. This corresponded temporally to the period of highest susceptibility to secondary bacterial infection. Ten days post virus infection, the enzyme levels had returned to baseline values. Aerosol challenge with bacteria (Pasteurella haemolytica) did not induce 2-5A synthetase activity in PBML, neither did it influence the kinetics of 2-5A synthetase induction by virus infection during a dual viral-bacterial infection. Pretreatment of animals with bovine recombinant interferons (IFNs) 0-96 h prior to virus challenge curtailed the viral infection and thus reduced the levels of 2-5A synthetase induced by endogenously produced IFN. A relationship between 2-5A synthetase levels on day 5 post virus infection and clinical outcome of the dual infection was noted. Moreover, the high 2-5A synthetase levels could be correlated with low plasma Zn levels, another indicator of clinical respiratory disease. These results indicate that these two parameters, 2-5A synthetase and plasma Zn, in combination have potential prognostic value in viral-bacterial infections of the respiratory tract.

Copper and zinc status in moderate alcohol intake

To determine the effects of moderate alcohol (ETOH) consumption on dietary intakes, serum and urine zinc (Zn) and copper (Cu) concentrations (conc), groups of nonsmoking, moderate drinkers, non-athletes, healthy young adult males aged 21-35 years and within 10% of ideal body weight, consumed 40g of ETOH/day as beer (fixed group) or maintained normal drinking habits (variable group) for 6 weeks, and then abstained for 3 weeks. A similarly described group of non-alcohol drinkers served as the control. There was no alcohol effect on dietary Zn or Cu intakes, however, the control group had significantly higher intakes of Zn than the drinking groups. Cu intakes were the same in all groups. Generally, the serum Zn and Cu conc of the drinking groups only, markedly rose during ETOH consumption and fell during abstention. Although this trend was not observed in the control group, they had higher serum Zn and Cu conc than the drinking groups. In general, urine Zn conc remained constant from baseline to consumption period and then decreased during the abstention period in all groups studied. Results indicate that moderate ETOH consumption raised serum Zn and Cu conc but had no effect on dietary intakes of these minerals or on urine Zn levels.

Appraisal of the methodology and applications for measurement of the zinc content of blood components as indicators of zinc status

Methods for the measurement of the zinc content of blood components (plasma, erythrocytes, platelets, mononuclear leukocytes, and polymorphonuclear neutrophils) as indicators of the zinc status of animals have been reviewed and evaluated. The values of plasma or serum zinc concentrations as indicators of zinc status in experimental animals or humans is questionable. Consequently, the zinc content of blood cellular components has been suggested as better indicators of zinc status. Methodological problems, such as incomplete cellular separation or zinc contamination, occur in some of the procedures applied to the quantitation of blood cellular component zinc. Specialized microprobe procedures involving, for example, proton-induced X-ray fluorescence, scanning ion technology, mass spectrometery, or laser microprobe mass analysis might be used to measure the absolute zinc level in individual cells subjected to minimal handling. Then, more conventional methods can be tested against the true standard. Nevertheless, there appears to be species differences in regard to the response of blood cellular zinc concentrations to dietary zinc deficiency. Blood cellular component zinc is conserved during severe zinc deficiency in the rat. In contrast, the zinc content of blood cellular components in humans may reflect the whole body zinc status.

Zinc concentration in umbilical cord tissue and cord plasma in appropriate-for-gestational-age babies

Zinc concentration in cord plasma was determined in 148 healthy appropriate-for-gestational-age babies delivered at various gestational ages. Zinc concentration in cord tissue was also determined in 62 of these babies. There was a significant rise in the cord tissue zinc concentration just after the 35th week of gestational age; thereafter the levels remained relatively unchanged. The cord plasma zinc concentration decreased slightly with increasing gestational age, but these changes were not significant. There was a statistically significant positive correlation between cord tissue zinc concentration and birth weight. No correlation was found between cord plasma zinc concentration and birth weight or cord tissue zinc concentration.

Zinc and copper nutriture in obese men receiving very low calorie diets of soy or collagen protein

Balance studies for Zn and Cu were conducted over 40 days in 10 obese men housed in a metabolic balance unit. Two weight reduction diets providing 400 kcal and 100 g protein daily were administered; to five subjects, a collagen diet which was severely deficient in both Zn and Cu, and to another five subjects, a soy diet which provided a marginal intake of Zn and an adequate intake of Cu. Zn and Cu content of diets, plasma, red blood cells, urine, and feces were determined during eight 5-day periods. Balances were corrected for lean tissue catabolism or deposition. Holter ECG monitoring and measurement of the QTc interval were done on days 0 and 40. Both diets resulted in elevated plasma and red blood cell concentrations of Zn and Cu and in high urinary and fecal losses of Zn. By day 40, 6 of 10 subjects were in negative Zn balance. Urinary Zn was inversely correlated with measures of lean tissue catabolism. During each period, Cu balance was markedly positive in the soy-diet group and negative in the collagen-diet group. Shortening of prolonged QTc intervals was related to the Cu but not Zn status of the individual.

The effects of severe zinc deficiency on intestinal amino acid losses in the rat

To determine whether intestinal amino acid losses might occur during zinc deficiency, labeled aminoisobutyric acid was given parenterally to zinc deficient rats and to appropriate zinc-sufficient controls. After 24 hours, the aminoisobutyric acid loss into the intestinal lumen was measured by in situ perfusion of isolated intestinal segments under conditions of either net water absorption or water secretion. Net amino acid losses were larger in the jejunum of the zinc deficient rats and losses were exacerbated during net water secretion in the jejunum and colon segments. The contribution of amino acid losses to fecal nitrogen, particularly during osmotic diarrhea, may be important in the growth retardation of zinc deficiency. Further, these alterations may indicate defective enterocyte transport functions during severe deficiency.

Determination of zinc in amniotic fluid in normal and high risk pregnancies

Taking the necessary precautions essential for accurate trace element analysis, the zinc concentrations of 227 samples of amniotic fluid taken at term were determined by means of neutron activation analysis. Half of the zinc was found to be bound to the particles present in amniotic fluid. In the control group (123 cases) the zinc concentrations ranged from 25-261 micrograms/l for untreated samples and from 14-143 micrograms/l when the samples were centrifuged for 10 min at 22 000 g prior to analysis. The values showed log-normal frequency distributions and were lower than any of the values published in the literature to date. No statistically significant difference could be found, when zinc concentrations of various risk groups (mothers suffering from gestosis or diabetes mellitus, newborns hypo- or hypertrophic, twin births) were compared with the zinc concentration of the control group. The amniotic fluid zinc concentration is not, therefore, a suitable indicator for the diagnosis of disturbances of the embryonic development.

Zinc and copper determination in microsamples of serum by flow injection and atomic absorption spectroscopy

A new approach to the direct determination of copper and zinc in serum and plasma is described. The sample is injected into a continuously pumped stream of water which is fed into the nebuliser of an atomic absorption spectrophotometer. Analytical results are obtained as a series of sharp peaks on a chart recorder. Analytical variables have been investigated, and the proposed method gave results comparable to those obtained using a conventional method based on precipitation of serum proteins with trichloroacetic acid. The proposed method takes less time to perform and was found to give more precise results than the conventional method. In addition, the flow injection analysis method can be performed using microsamples (10-100 microliters) and is thus ideally suited for use on children.

Resolution of age-dependent reference intervals: polynomial regression methodology with applicability to plasma zinc levels in a childhood population

We present a systematic parametric method for resolving age-related reference intervals based on differential-polynomial regression analysis. Application of this method to plasma zinc concentrations in a childhood population results in a third degree polynomial expression from which two statistically independent age-reference intervals are derived. The method appears to be useful in describing age-dependent concentration trends particularly for pediatric and geriatric populations.