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Biomedical subjects

D C Davidson

Publications and source records attributed to D C Davidson.

At least 37 records · Page 2Linked to original sources

Maternal phenylketonuria.

The exact mechanism of fetal damage in maternal phenylketonuria (PKU) is uncertain and although the fetus is heterozygotic for the gene coding for phenylalanine hydroxylase its immature hepatic enzyme system may be the reason for its inability to deal adequately with transplacental phenylalanine uptake. Several aspects of the management of maternal PKU are discussed and several case studies are presented. Dietary treatment should begin preconceptually despite evidence that post-conceptual treatment can have an acceptable outcome. Maternal recognition of the need for pre-conceptual treatment should increase with improvements in intellectual abilities of PKU girls resulting from neonatal screening and appropriate dietary management.

Adolescent↗

ABO incompatibility.

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ABO Blood-Group System↗

Does ABO incompatibility matter?

The incidence and severity (peak serum bilirubin concentration) of clinically detectable jaundice was determined retrospectively in 110 elution positive cases of ABO incompatibility. Neither the incidence nor the severity of jaundice in the study group differed significantly from a control group. In the individual case Coombs positivity and/or a strongly positive elution test may be a helpful predictor of jaundice occurring but not of its severity.

ABO Blood-Group System↗

Early congenital syphilis still occurs.

Seven cases of early congenital syphilis have been recorded in the past 10 years in the Mersey Regional Health Authority. Antenatal serology was initially negative in five mothers, who were either incubating or acquired the infection later, and treatment had probably failed in two women given erythromycin for syphilis during pregnancy. Serology should be repeated later in pregnancy in those at high risk. Social factors that define this group include women who book for antenatal care late in pregnancy, have a past history of sexually transmitted disease, and have multiple consorts. Clinical signs in the infant such as failure to thrive, hepatosplenomegaly, symmetrical rash, rhinitis, and osteochondritis should alert the clinician to the possibility of congenital syphilis. Adequate management of mother and baby requires close liaison between the genitourinary physician, microbiologist, obstetrician, and paediatrician. Penicillin remains the treatment of choice.

Adult↗

Fatal hepatitis B in infant born to a HBsAg carrier with HBeAb.

Fulminant hepatic failure occurred in an 11 week old baby of a Caucasian mother who was hepatitis B surface antigen positive, B e antigen negative, and B e antibody positive. Infants of hepatitis B e antigen positive mothers receive immunoprophylaxis against hepatitis, unlike those born to mothers who are B e antibody positive.

Carrier State↗

Quantitative bacteriology of peripheral venous cannulae in neonates.

In a study of 50 peripheral venous cannulae removed from neonates in the special care baby unit, quantitative and qualitative techniques for cannula culture were compared and the results correlated with detailed clinical information. High-density colonization was demonstrated on the external and internal surfaces of nine, and on the external surface alone of four, cannula tips. Internal surface colonization was always associated with heavy external surface growth. In predicting high-density colonization by quantitative methods, qualitative culture in broth was 100% sensitive and 89% specific. There was a significant association between high-density colonization of the cannula tip and hub colonization, surrounding skin colonization, longer duration of cannula insertion, and slower average infusion rate. Similar organisms were isolated more frequently from the cannula tip and the hub than from the cannula tip and surrounding skin. These findings indicate that peripheral venous cannulae are a potential source of infection in neonates, that there is no advantage of techniques that identify internal surface colonization, and that most cannula tip infections have their origin in a colonized hub.

Bacteria↗

The effect of treatment on zinc, copper and calcium status in children with phenylketonuria.

The trace element status of 25 children receiving a low phenylalanine diet for a treatment of phenylketonuria was studied using hair and serum samples. Hair trace element and calcium concentrations were assayed using X-ray microanalysis and compared with samples from sibling controls. Plasma, zinc and copper levels were compared with unselected hospital attenders. PKU patients were found to have significantly lower hair zinc (P less than 0.001) and calcium (P less than 0.01) concentrations and significantly hair copper (P less than 0.001) concentrations compared with controls. Plasma zinc levels were below the lower limit of normal (9.6 mumol l-1) in 8 of 19 patients (42%) in whom it was measured. The relative zinc deficiency in PKU patients may result from a competitive inhibition of absorption by copper or other metals supplemented in the diet.

Adolescent↗