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Biomedical subjects

J K Friel

Publications and source records attributed to J K Friel.

At least 37 records · Page 2Linked to original sources
PubMed1992

Copper status of very low birth weight infants during the first 12 months of infancy.

The Cu intake and status of 106 very low birth weight (VLBW) infants (birth weight 1152 +/- 251 g, gestational age 29 +/- 3 wk, mean +/- SD) were determined approximately 1 mo before hospital discharge, at discharge (time 0), and at 3, 6, 9, and 12 mo +/- 3 wk corrected for gestational age. Infants were fed either formula plus supplemental Zn/Cu (SUPPL, n = 29); formula plus placebo (PLAC, n = 26); or a low birth weight formula (LBWF, n = 26) or were breast-fed (BRMLK, n = 25). Plasma Cu levels in the formula-fed infants increased significantly at each time period with no significant differences between feeding groups. Hair Cu was significantly higher in the SUPPL group compared to the PLAC, LBWF, and BRMLK groups at 3 and 6 mo. Erythrocyte Cu,Zn-superoxide dismutase (CuZnSOD) activity was lowest in the PLAC group. Cu intake was positively correlated with both hair Cu (r = 0.291, p less than 0.0001) and erythrocyte CuZnSOD activity (r = 0.281, p less than 0.001) but not with plasma Cu. An increasing number of formula-fed infants had very low CuZnSOD activity (less than 2 SD below mean) with increasing age (n = 1, 2, 8, 11, and 13 infants at times 0, 3, 6, 9, and 12 mo, respectively). At 12 mo, approximately one third of the formula-fed VLBW infants in this study had low Cu status as assessed by CuZnSOD activity. Infants with the lowest CuZnSOD activity were those with the largest weight gains from 0 to 6 mo and were observed in all formula-fed groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Weight↗
PubMed1990

Iron status of very-low-birth-weight infants during the first 15 months of infancy.

The adequacy of iron stores in infants of very low birth weight (defined as less than 1500 g) in Canada is unknown. We monitored the iron status of 81 such infants at 3, 6, 9, 12 and 15 months of age. All of the infants were fed formula fortified with iron (13 mg/L) for at least 6 months, starting at 2 months of age. The plasma ferritin level decreased after the formula was no longer used. Although 90% of the infants were given cereal fortified with iron (30 mg of iron per 100 g) by 9 months of age, the plasma ferritin level continued to decrease. The level was less than 10 micrograms/L in 54% of the infants at 12 months of age and in 74% at 15 months; this indicated depleted iron stores. Because of delayed development very-low-birth-weight infants eat small amounts of cereal and therefore require iron-fortified formula throughout infancy.

Aging↗
PubMed1990

Analysis of biological reference materials, prepared by microwave dissolution, using inductively coupled plasma mass spectrometry.

A procedure has been developed for the analysis of biological materials by inductively coupled plasma mass spectrometry (ICP-MS). Fast, efficient and complete sample digestion is achieved by a combined microwave-nitric acid/open beaker-nitric acid-hydrogen peroxide procedure. The ICP-MS analysis is performed with an on-line five-element internal standard to correct for matrix and instrumental drift effects. Results are presented for 24 elements in three biological reference materials (National Institute of Standards and Technology Standard Reference Materials 5277a Liver and 1566 Oyster and International Atomic Energy Agency Certified Reference Material H4 Animal Muscle). For all elements significantly above the detection limit and reagent blank concentrations, good agreement exists between ICP-MS and certified values.

Animals↗
PubMed1989

Trace elements in meconium from preterm and full-term infants.

Meconium samples from 23 preterm infants (birth weight = 1,097 +/- 359 g; gestational age 29 +/- 3 weeks, mean +/- SD) and 27 full-term infants (3,453 +/- 476 g; 39.5 +/- 1 weeks) were analyzed for zinc, copper, manganese, chromium and iron by atomic absorption spectrometry. Compared to meconium from preterm infants, full-term infants had an elevated (p less than 0.05) total excretion (microgram) of zinc (957 +/- 545 vs. 503 +/- 506), copper (245 +/- 256 vs. 128 +/- 94) and manganese (62 +/- 55 vs. 29 +/- 29), but not iron (190 +/- 147 vs. 332 +/- 532) or chromium (0.4 +/- 0.19 vs. 0.75 +/- 1.0). Two preterm infants had high losses (1.5 and 2 mg) of iron in their meconium. Zinc, copper and manganese losses into meconium appear to increase with gestation, whereas iron and chromium losses occur early in gestation and may be reabsorbed by term.

Chromium↗
PubMed1987

Cadmium-induced immunopathology is prevented by zinc administration in mice.

Six-week-old C57BL/6 male mice were exposed to 50 mg cadmium/L drinking water (50 ppm) for 3 wk, and killed at 0, 3 and 6 wk after cessation of treatment. In some groups, 500 mg zinc/L was added to the drinking water (500 ppm) with or after cadmium treatment. The number of direct and indirect splenic plaque-forming cells was higher in cadmium-treated mice at 0 wk than in untreated controls. Concurrent zinc administration prevented the enhancement of plaque-forming cell response. Proliferative response of spleen cell culture to the T-cell mitogens phytohemagglutinin and concanavalin A was slightly high in cadmium-treated mice at 0 wk and zinc administered after exposure to cadmium tended to lower it. The number of Lyt-2 positive cells in the spleen was lower and the ratio of L3T4 to Lyt-2 positive cells, reflecting the balance of immunoregulatory T-lymphocytes, was higher after cadmium treatment than in untreated controls. Concurrent zinc administration prevented the alteration of T-cell subsets. Cadmium and zinc treatment had no effect on liver, kidney, spleen and thymus weights and lymphocyte content of spleen, thymus and peripheral blood. Use of immunofluorescence with anti-mouse IgG and C3 showed no evidence of an autoimmune reaction in kidney sections. Liver and kidney cadmium concentrations were high at all observation times in the cadmium-treated animals. Tissue cadmium levels were lower in mice treated with both zinc and cadmium than in those treated with cadmium alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Dry- and wet-ashing techniques compared in analyses for zinc, copper, manganese, and iron in hair.

Preparation of hair specimens for trace-metal analyses is routinely done by wet- or dry-ashing. Wet-ashing is more time consuming than dry-ashing and can be dangerous. We wished to determine if dry-ashing was a suitable alternative to wet-ashing with HClO4:HNO3 or HNO3 alone in preparing hair for measurement of zinc, copper, iron, and manganese by atomic absorption spectroscopy. Concentrations of Zn, Cu, and Mn were not differently affected in hair that was dry- or wet-ashed. Analytical recovery of these elements added to hair samples ranged from 102 to 108%; day-to-day CVs were less than 5%. Fe was lost during dry-ashing of hair, and wet-ashing with HNO3 produced results for Fe comparable with those obtained with HClO4:HNO3. Therefore we recommend dry-ashing of hair to be analyzed for Zn, Cu, and Mn, but wet-ashing with HNO3 for assays of Fe.

Copper↗
PubMed1985

Dietary zinc intake and growth during infancy.

Energy, protein, zinc intake, and weight and length were monitored at 3, 6, and 12 months in 50 preterm infants (corrected for gestational age) (mean birthweight, 1,054 +/- 234 g; mean gestation, 29 +/- 2.5 weeks) and 60 full-term infants (mean birthweight, 3,509 +/- 269 g; mean gestation, 40 +/- 1 weeks). Mean energy and protein intake (per kilogram body weight) was higher (p less than 0.05) for the preterm infants at all times and met the recommended levels for preterm infants. No significant differences in zinc intake (per kilogram body weight) between the two groups existed, and at 3 months, mean zinc intake in the preterm group (per kilogram body weight) was below the recommended level for full-term infants. At no time were the growth percentiles of the preterm group equal to those of the full-term group. Multiple regression equations predicting length at 3 months and weight at 12 months for all the infants were significant, the significant variables being length at birth and zinc intake (milligrams per day) at 3 months, and weight at birth and dietary zinc intake (milligrams per day) at 12 months, respectively. Results indicate that zinc intake played a more important role in explaining the length at 3 months and weight at 12 months than did any other variables, including intakes of protein and energy, gestational age, socioeconomic index of the father, midparent height, sex, and age of introduction of solid foods. Results thus support the suggestion that infants, especially those born prematurely, are at risk for inadequate intake of dietary zinc.

Body Height↗
PubMed1984

Serum zinc, copper, and selenium concentrations in preterm infants receiving enteral nutrition or parental nutrition supplemented with zinc and copper.

Fifteen enterally fed preterm infants not receiving additional trace element supplements and 22 preterm infants receiving total or partial parenteral nutrition supplemented with zinc at 350 micrograms/kg/day and copper at 20 micrograms/kg/day were examined 1, 7, 14, 21, and 28 days after birth. Mean serum Zn concentrations in the parenteral group remained relatively constant and were significantly higher (P less than 0.01) at day 21 than the value for the enteral group. In contrast, a significant decline in mean serum Zn concentrations occurred between days 1 and 21 in the enteral group. The mean serum Cu concentrations in the parenteral group rose during the first week, and were significantly higher at days 14 and 21 than corresponding values in the enteral group. This trend did not result from copper supplementation alone but was also attributed to the presence of ceruloplasmin in blood transfusions. Mean serum Se concentrations did not change significantly, either between or within the two groups, except during the first week, at which time levels rose in the parenteral group. The addition of Zn, Cu, and probably of Se to parenteral infusates, allows the maintenance of appropriate serum values.

Ceruloplasmin↗
PubMed1984

A comparison of the zinc, copper and manganese status of very low birth weight pre-term and full-term infants during the first twelve months.

During a longitudinal study, hair samples and dietary intake data were collected from 50 pre-term (mean birth weight = 1054 +/- 234 g, mean gestational age = 29 +/- 2.5 weeks) and 60 full-term infants (mean birth weight = 3509 +/- 269 g, mean gestational age = 40 +/- 1 weeks) at 3, 6 and 12 months of age. Mean daily zinc, copper and manganese intakes were calculated using three-day dietary records and test-weight data for the breast-fed infants. Hair samples were analyzed for these elements by instrumental neutron activation analyses. The medium hair zinc concentration in the pre-term group at six months (81 micrograms/g) was lower (p less than 0.05) than that of the full-term group (144 micrograms/g) and was associated with lower mean dietary zinc intakes at 3 and 6 months. At 12 months, the median hair copper (12.5 micrograms/g) and manganese (0.18 micrograms/g) concentrations for the pre-term were lower (p less than 0.05) than those of the full-term infants (Cu = 16.5 micrograms/g; Mn = 0.25 micrograms/g) and were also associated with low dietary copper and manganese intakes.

Copper↗
PubMedDate not supplied

Determination of isotope ratios in human tissues enriched with zinc stable isotope tracers using inductively coupled plasma-mass spectrometry (ICP-MS).

Enriched fecal and urine samples were prepared using ion-exchange column chromatography for analysis by Inductively Coupled and Fast Atom Bombardment Mass spectrometry (ICP-MS, FAB-MS) to compare precision between methods. Unenriched samples of human milk, feces, and whole blood were prepared similarly to monitor instrumental precision and analytical error. A least squares fit of the ICP-MS results vs the FAB-MS for 70Zn/64Zn gave a slope of 0.98, with a relative standard deviation (RSD) of only 0.7%. The results for 68Zn/64Zn gave a slope of 0.82, with a RSD of 14%. For unenriched tissues, all potential interferences were removed by the preparation procedure with no significant differences between preparation for isotope ratios of 70Zn/64Zn, 68Zn/64Zn, 67Zn/64Zn, and 66Zn/64Zn. Poisson counting statistics are a major contribution to the total analytical error indicating the usefulness of this procedure for enrichment studies.

Animals↗
PubMedDate not supplied

Zinc, copper, manganese, and iron balance of parenterally fed very low birth weight preterm infants receiving a trace element supplement.

To evaluate a pediatric trace element supplement (Ped-El, Pharmacia) 18 metabolic balance studies were completed in 13 infants (mean birth weight 909 +/- 67 g, x +/- SEM; mean gestational age 27.2 +/- 1 weeks) who received total parenteral nutrition. The supplement supplied 40 micrograms/kg/day of zinc resulting in negative retention of 226 micrograms/kg/day. Copper infused at 20 micrograms/kg/day led to a positive retention of 8 micrograms/kg/day and an increase in serum Cu (p less than 0.05) not related to Cu intakes. Manganese infused at 40 micrograms/kg/day was nearly all retained (88 +/- 16% retention). Iron infused at 120 micrograms/kg/day led to a positive retention of 93 micrograms/kg/day. Although plasma ferritin and percent transferrin saturation were elevated, only plasma Fe values were correlated with Fe intake. This trace element supplement does not appear suitable for very low birth weight preterm infants.

Copper↗
PubMedDate not supplied

Thiamine, riboflavin, folate, and vitamin B12 status of low birth weight infants receiving parenteral and enteral nutrition.

Thirty infants were randomly assigned to receive either 3 mL of MVI-Pediatric supplement (PAR3 group, parenterally fed) or 2 mL (PAR2 group, parenterally fed). For the first week, 100% received total parenteral nutrition (TPN), 50% by the second, and less than 33% by the third. Eighteen control infants received enteral feeds of infant formula. Baseline (before TPN) and subsequent weekly blood samples, dietary data, and 24-hour urine collections were obtained. The adequacies of thiamine and riboflavin were assessed by the thiamine pyrophosphate effect and erythrocyte glutathione reductase activity, respectively. Urinary thiamine and riboflavin levels were measured by fluorometry. Plasma folate, red blood cell folate, urinary folate, and plasma vitamin B12 concentrations were determined by radioassay. No differences between groups were observed in thiamine pyrophosphate effect, erythrocyte glutathione reductase activity, urinary B1 or B2, or red blood cell folate levels at any time. Plasma folate differed (p less than .05) among the PAR3 group (24 +/- 7 ng/mL), and both the PAR2 (13 +/- 5 ng/mL) and enterally fed (ENT) groups (16 +/- 3 ng/mL) before the initiation of feeds, at week 1 (PAR3 = 32 +/- 15 ng/mL; PAR2 = 18 +/- 4 ng/mL; ENT = 19 +/- 9, ng/mL) and between the PAR3 (30 +/- 16 ng/mL) and PAR2 (16 +/- 4 ng/mL) infants at week 2. Plasma vitamin B12 levels differed among the ENT groups (551 +/- 287 pg/mL) and both the parenteral groups (PAR2 = 841 +/- 405 pg/mL; PAR3 = 924 +/- 424 pg/mL) at week 1 and between the ENT (530 +/- 238 pg/mL) and PAR3 (999 +/- 425 pg/mL) groups at week 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMedDate not supplied

Intravenous iron administration to very-low-birth-weight newborns receiving total and partial parenteral nutrition.

BACKGROUND: Intravenous iron supplements are not routinely administered to very-low-birth-weight newborns receiving total parenteral nutrition because of the possible increased risk of infection and because iron needs may be met with blood transfusions. METHODS: To assess the benefits of a prudent IV iron supplement (200 to 250 micrograms/kg/d), 26 very-low-birth-weight newborns (birth weight, 1005 +/- 302 g; gestational age, 28 +/- 2.3 weeks; mean +/- SD) were randomly allocated to receive total parenteral nutrition without iron (No-Iron) or with iron supplied as iron dextran (Iron). These newborns were followed at baseline (2 to 3 days after birth) and at weeks 1 to 4 thereafter. At each sampling time, urine samples, fecal samples (rarely), unused total parenteral nutrition solutions, blood products, and a blood sample (1 mL) were collected. RESULTS: There were no differences between the two groups in anthropometric measurements, hematologic or biochemical parameters, number or amount of blood transfusions (2.3 +/- 1.9), amount of blood removed for diagnostic purposes (44 +/- 16 mL), or number of septic events (n = 16). There was no difference between the groups for the total iron excreted; however, the Iron group retained more iron. Iron balance was negative for all but 10 newborns (No-Iron, 3; Iron, 7) throughout the study. CONCLUSIONS: A total iron intake of 400 micrograms/kg/d, half of which was provided by IV iron, is not sufficient to maintain iron balance or to meet fetal accretion rates (1000 micrograms/kg/d) in very-low-birth-weight newborns receiving total parenteral nutrition. Furthermore, endogenous iron from blood transfusions does not provide an adequate supply of iron.

Anthropometry↗
PubMedDate not supplied

Molybdenum requirements in low-birth-weight infants receiving parenteral and enteral nutrition.

BACKGROUND: Molybdenum (Mo) is an essential trace element required by three enzymatic systems, yet there are no reports of Mo deficiency in infants. Low-birth-weight infants (LBW) might be at risk for Mo deficiency because they are born before adequate stores for Mo can be acquired, they have rapid growth requiring increased intakes, and they frequently receive supplemental parenteral nutrition (SPN) and total parenteral nutrition (TPN) unsupplemented with molybdenum. METHODS: To investigate Mo requirements of LBW infants (n = 16; birth weight, 1336+/-351 g; gestational age, 29.8+/-2.5 weeks; M+/-SD), the authors collected all feeds, urine, and feces prior to TPN (baseline, n = 16, collections = 16), during TPN (n = 9, collections = 19), during SPN (n = 13, collections = 17), and after one week of full oral feeds (FOFs) of formula or human milk (FOF, n = 16, collections = 16). RESULTS: Infant weights at collection times were: 1.3+/-0.3 g, 1.27+/-0.4 g, 1.4+/-0.3 g, and 1.7+/-0.5 g, respectively. Mo intake was 0.03+/-0.1 microg/d, 0.34+/-0.1 microg/d, 1.25+/-1.7 microg/d, and 6.1+/-2.5 microg/d. Mo output was 0.64+/-0.6, 0.34+/-0.5, 0.68+/-0.8, and 4.1+/-2.5 microg/d. Mo balance at these times was -0.60+/-0.5, -0.001+/-0.5, 0.57+/-1.9, and 2.0+/-2.9 microg/d. Mo balance increased with time, yet some infants were always in negative balance, even though Mo intakes exceeded recommendations. CONCLUSIONS: The authors speculate that an intravenous intake of 1 microg/kg/d (10 nmol/kg/d) and an oral intake of 4-6 microg/kg/d (40-60 nmol/kg/d) would be adequate for the LBW infant.

Enteral Nutrition↗
PubMedDate not supplied

Eighteen-month follow-up of infants fed evaporated milk formula.

In parts of Canada including Newfoundland and Labrador and among Aboriginal peoples, infants still consume evaporated milk (EM) formulas for cultural and economic reasons. At 3 and 6 months, full-term infants fed EM (n = 30) received low intakes of iron, thiamine, selenium and had higher weight velocity than breastfed (BF, n = 29) infants. EM infants had greater anemia, lowered transketolase activity (thiamine) and lowered glutathione peroxidase (selenium) activity (p < 0.05). To determine the later effect of early feeding deficit on nutritional status, we examined these same infants at 18 months of age. At that time, there were no differences in dietary intakes of energy, protein, zinc, copper, selenium and iron, nor in plasma levels of zinc, copper, vitamin C, nor in red blood cell activity levels of glutathione reductase (riboflavin), transketolase, glutathione peroxidase, nor in superoxide dismutase. However, EM infants weighed more and were more likely to visit a physician, have anemia, and have iron depletion than were BF infants. We conclude that infants consuming evaporated milk formulas should receive iron supplements throughout infancy.

Animals↗
PubMedDate not supplied

The effect of a promotion campaign on attitudes of adolescent females towards breastfeeding.

We determined the effect of a breastfeeding promotional campaign on attitudes and knowledge of adolescent females, by use of a pre- and post-campaign survey. The total population surveyed consisted of 463 girls with a mean age of 16 distributed throughout three grades (10 to 12) in two high schools. The campaign ran for five weeks including a television commercial and advertisement in local newspapers. Attitudes towards breastfeeding were positively influenced by the campaign but only the television commercial was found to change attitudes (p less than 0.05). The campaign did not increase knowledge scores. Those completing the pre-test were found to have both a higher knowledge and attitude score on the post-test (P less than 0.05) than those who did not complete the pre-test. We suggest that adolescents will develop a positive attitude to breastfeeding when actively targeted by media and when exposed to breastfeeding information in the classroom.

Adolescent↗