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Biomedical subjects

I C Normand

Publications and source records attributed to I C Normand.

At least 19 recordsLinked to original sources
PubMed1992

Phosphatidylcholine composition of endotracheal tube aspirates of neonates and subsequent respiratory disease.

The phosphatidylcholine (PC) content of the initial endotracheal tube aspirate was measured in 105 infants intubated for resuscitation or for ventilation for respiratory distress syndrome, using high performance liquid chromatography and postcolumn fluorescence derivitization with diphenyl-1,3,5-hexatriene. Sixty eight had measurable PC. Of the infants who developed respiratory distress syndrome, with or without subsequent chronic lung disease, neither the percentage of dipalmitoylphosphatidylcholine (DPPC) nor the ratio of DPPC to palmitoyloleoylphosphatidylcholine (POPC), showed any correlation with gestational age. However, both parameters were significantly lower overall in this group than in the group of infants who did not develop respiratory distress syndrome. Infants with a ratio of DPPC:POPC less than 3.0 developed respiratory distress syndrome irrespective of gestational age, but there was considerable overlap between groups for values greater than this. The infants with respiratory distress syndrome who went on to develop chronic lung disease had the same initial PC profile as those with respiratory distress syndrome who did not develop chronic lung disease, but differed as a group by being lighter and more premature. The development of chronic lung disease was not associated with a particular initial PC composition. Other factors related to increasing prematurity must therefore be involved in rendering infants vulnerable to developing chronic lung disease.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1992

Turnover of exogenous artificial surfactant.

The turnover of the artificial surfactant Exosurf after its administration to infants with respiratory distress syndrome was studied. High performance liquid chromatography was used to compare the phosphatidylcholine (PC) composition of serial endotracheal tube secretions from three groups of infants. There were 22 infants who received two doses of Exosurf in 24 hours (group 1), 10 infants who received four doses in 36 hours (group 2), and 41 control infants who did not receive Exosurf. Two parameters were studied: (i) dipalmitoylphosphatidylcholine (DPPC), which is present in both Exosurf and endogenous surfactant, expressed as a percentage of total PC (% DPPC) and (ii) the ratio of DPPC to the entirely endogenous palmitoyloleoylphosphatidylcholine (DPPC:POPC ratio). The administration of Exosurf produced changes in endotracheal tube aspirate PC composition that were detectable for over one week. Four doses of Exosurf in 36 hours prolonged the persistence of these changes compared with two doses in 24 hours, but the numbers of infants were small, and should not be over-interpreted. We conclude that after giving two doses of Exosurf, further doses might best be delayed until after two days, and that further clinical evaluation of dosage regimens is required.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1991

Mechanisms of phosphatidylcholine acyl remodeling by human fetal lung.

The molecular specificity of phosphatidylcholine (PC) synthesis by the de novo pathway in postmortem samples of human fetal lung (15 to 20 wk of gestation) was determined from the incorporation pattern in isolated microsomal preparations of CDP:[14C]choline into individual molecular species of PC. These analyses are based on the assumption that the molecular species composition of the pool of endogenous diacylglycerol used for PC synthesis by isolated microsomes reflects that of the authentic pool of diacylglycerol converted to PC by intact cells. Comparison of this microsomal incorporation pattern of radiolabel into PC with tissue PC composition suggested that even at this early stage of gestation 50% of lung dipalmitoyl PC was derived from synthesis de novo, with the remainder coming from acyl remodeling mechanisms. Analysis of PC synthesis de novo by organ cultures of human fetal lung showed that these acyl remodeling mechanisms were lost in culture. Despite evidence for differentiation of type II alveolar epithelial cells in culture, equilibrium labeling of PC with [14C]choline over 18 h resulted in a progressive decline in fractional incorporation into dipalmitoyl PC with time in culture. By 4 days in culture, this value was no different from the fractional incorporation of CDP:[14C]choline into microsomal PC in vitro over 3 h. The pattern of PC synthesized was not altered when total PC synthesis was stimulated by exposure of cultures to dexamethasone and tri-iodothyronine but was readily manipulated by exposure to exogenous fatty acids. These results demonstrate for the first time the activity of PC acyl remodeling mechanisms in human fetal lung, well before the initiation of surfactant production.(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗
PubMed1985

The proteins of human lung surfactant.

Human pulmonary surfactant was purified from bronchoalveolar lavage of patients. The proteins present in surfactant were analyzed by SDS-polyacrylamide gel electrophoresis into serum and non-serum components. One non-serum surfactant protein (Mr = 43 000) was then identified in the 100 000 X g supernatant of a lung homogenate on the basis of phospholipid binding. This lung protein was purified and partially characterized. The presence of 3-methyl histidine and reaction in Western blot analysis with antibody against chicken muscle actin both strongly suggested that the 43 000 Da protein of human surfactant is indeed cytoplasmic actin. It is proposed that this surfactant protein is involved in the secretion and not necessarily in the function of surfactant.

Amino Acids↗
PubMed1985

Development of new renal scars: a collaborative study.

In a study of the factors surrounding the development of renal scars clinical data and serial radiographs were analysed in 74 infants and children (66 girls and eight boys) without duplex kidney or obstruction. The development of new scars was seen radiologically in 87 kidneys (74 previously normal and 13 previously scarred). New scarring was extensive in 16 kidneys. Thirty four children were aged 5 or over when scarring occurred. Urinary infection occurred in all the children. Diagnosis and effective treatment were delayed in 45 of them; 58 suffered further urinary infections between the baseline intravenous urogram and the first showing new scarring. Vesicoureteric reflux was seen in 67 of the children. Investigation and treatment varied widely, and few children received long term prophylaxis. Social problems interfered with the management of 22 children. Early diagnosis, prompt effective treatment, investigation, and long term supervision of children with urinary infection are essential if renal scarring is to be reduced; those over the age of 5 are still vulnerable.

Child↗
PubMed1982

Alpha-1-antitrypsin deficiency presenting as a bleeding diathesis in the newborn.

Three cases of alpha-1-antitrypsin deficiency are reported. Each infant presented in the newborn period with a haemorrhagic tendency which responded to vitamin K. Two of them subsequently developed cirrhosis, and Case 2 is one of the few reported cases in infantile cirrhosis associated with the heterozygous protease inhibitor (Pi) SZ phenotype. On the basis of these 3 patients we feel that the exclusion of alpha-1-antitrypsin deficiency by Pi phenotyping should be considered in any baby presenting with a bleeding diathesis, especially in view of the genetic implications of the homozygous Pi ZZ phenotype.

Hemorrhagic Disorders↗
PubMed1977

Disappearance of vesicoureteric reflux during long-term prophylaxis of urinary tract infection in children.

Seventy-five children aged 3 weeks to 12 years and found on investigation of symptomatic urinary infection to have vesicoureteric reflux were managed conservatively with continuous low-dose prophylaxis. Serial cystographic and renal growth studies were performed during seven to 15 years' follow-up. Reflux disappeared spontaneously in 53 children (71%) and from 79% of the affected ureters. This occurred at any age and not only in infancy or at puberty. The initial severity or reflux was the most important factor affecting the outcome. Reflux disappeared from 85% of ureters of normal calibre but from only 41% of dilated ureters. Gross reflux associated with existing severe renal scarring was least likely to disappear. Nevertheless, reflux stopped in 12 of the 19 initially scarred renal units (63%). Reflux was as likely to disappear in children who had a recurrence of urinary infection as in those who had no further infection. Renal growth appeared to be normal in 93% of kidneys and fresh or extending scarring was seen in only two children. Management programmes for children with vesicoureteric reflux should take into account the self-limiting nature of three-quarters of the reflux found on investigating uncomplicated urinary tract infection.

Anti-Infective Agents↗
PubMed1977

Cartilage hair hypoplasia.

Six cases of cartilage hair hypoplasia from five kindreds are described. They demonstrate variation in the expression of clinical features such as sparsity of hair, hair calibre, radiological changes, short stature and the extent of the disproportion between sitting height and stature.

Age Factors↗