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Biomedical subjects

J Farquharson

Publications and source records attributed to J Farquharson.

28 records · Page 2Linked to original sources
PubMed1986

Dietary copper intake in artificially fed infants.

Plasma concentrations of copper and zinc and leucocyte concentrations of zinc were measured in mothers during later pregnancy, at delivery, and 8-10 weeks after birth, and plasma concentrations of copper and zinc were measured in their infants at delivery and 8-10 weeks after birth. The 145 infants were either breast fed or fed one of two milk formulas supplying copper at different concentrations. None of the infants achieved the minimum copper intakes recommended by the World Health Organisation (WHO). At 2 months of age there were no major differences in growth or health detected in infants fed the different copper intakes. Infant birth weight correlated well with the ratio of maternal venous plasma zinc:maternal leucocyte zinc at delivery. Maternal venous plasma copper and zinc concentrations at birth correlated with umbilical venous plasma copper and zinc concentrations. Infants fed the higher copper content formulas had a low mean plasma zinc concentration without a significant increase in the mean plasma copper concentration. The present WHO recommendations regarding minimum copper intakes for infants fed formulas cannot be achieved with currently available formulas and are probably wrong.

Breast Feeding↗
PubMed1985

Quantitative determination of phosphatidylglycerol in amniotic fluid by enzymatic assay.

Phosphatidylglycerol (PG) was extracted from 54 human amniotic fluids for the assessment of fetal lung maturity. The PG values were derived from an enzymatic assay involving initial conversion of PG to glycerol by phospholipase C and alkaline phosphatase with subsequent analysis of the glycerol formed. This method proved to be reliable when compared with a method for two-dimensional thin layer chromatographic (2D TLC) analysis of amniotic fluid phospholipids. The results revealed that in all but one of 27 amniotic fluids in which no PG was detected by 2D TLC, enzymatic PG concentrations were less than or equal to 1.5 mumol/l and out of these, from 10 newborn infants delivered within 72 h of sampling, 4 developed respiratory distress syndrome (RDS). Conversely, in all but one of 27 amniotic fluids found to contain PG by 2D TLC, enzymatic PG concentrations were greater than 1.5 mumol/l and except for one subject from non-identical twins, no infants developed RDS.

Alkaline Phosphatase↗
PubMed1985

Copper deficiency in the preterm infant of very low birthweight. Four cases and a reference range for plasma copper.

Four preterm infants of very low birthweight (less than 1500 g) developed signs of copper deficiency between age 8 and 10 weeks. All had required prolonged ventilatory support, parenteral nutrition, and nasojejunal feeding. The clinical features, which included osteoporosis, oedema, anaemia, neutropenia, and late apnoea improved when the oral copper intake was increased. Diagnosis was made more difficult because a suitable reference range for plasma copper was not available. Serial measurements of plasma copper in 39 preterm infants who had no important medical problems were used to produce a reference range for plasma copper from 30 weeks' gestation to term plus seven weeks. This information will aid recognition of hypocupraemia in the very low birthweight infant who is particularly at risk of copper deficiency.

Copper↗
PubMed1977

The forms of vitamin B12 on the transcobalamins.

1. The transcobalamins from normal serum were obtained in two fractions. One contained transcobalamin I and transcobalamin III: the other contained transcobalamin II. The forms of vitamin B12 in the two fractions were then examined. 2. Methylcobalamin and adenosylcobalamin were found in both fractions. Hydroxocobalamin was found in the fraction containing transcobalamin I and transcobalamin III. Cyanocobalamin was found in both fractions in two cases, in the transcobalamin III fraction only in one case and was absent in one case.

Blood Proteins↗
PubMed1977

Conversion of hydroxo(aquo) cobalamin to sulfitocobalamin in the absence of light: a reaction of importance in the identification of the forms of vitamin B12, with possible clinical significance.

During determinations of the forms of vitamin B12 in foods and human tissues several samples yielded a growth zone on bioautography which was distinct from those due to methylcobalamin, adenosylcobalamin, hydroxocobalamin, or cyanocobalamin. The material responsible for this growth zone was identified as sulfitocobalamin and the mechanisms in its formation from hydroxocobalamin involve absence of light and the presence of bisulphite ions derived from atmospheric sulfur dioxide or indigenous sulfite ions. The formation of sulfitocobalamin during the extraction of cobalamins from foods and tissues can be prevented by reception and homogenization of the material in an ammonia buffer instead of water; the hydroxocobalamin is then converted to ammonia cobalamin, which is more resistant to attack by (bi)sulfite ions. The conversion of hydroxo(aquo)cobalamin to sulfitocobalamin in the dark can be rapid, and materials for analysis should be placed in the ammonia buffer before darkroom work is begun. The rapid conversion of hydroxo(aquo)cobalamin to sulfitocobalamin in the dark raises the possibility that hydroxocobalamin in foods may be converted to the less well absorbed sulfitocobalamin in the upper gastrointestinal tract.

Animals↗
PubMed1976

The forms of vitamin B12 in foods.

1. The forms of vitamin B12 were determined in foods, most of which had been prepared for consumption. 2. Five forms were detected: adenosylcobalamin, hydroxocobalamin, methylcobalamin, cyanocobalamin and sulphitocobalamin. Adenoxylcobalamin and hydroxocobalamin were the predominant forms. 3. The intestinal absorption of [57Co]sulphitocobalamin was estimated and found to be lower than that of [58Co]cyanocobalamin.

Adult↗