Pediatric RadiologyContinuing Medical Education Activity

Pediatric Radiology CME Activity

Pediatric Radiology Continuing Medical Education Activity     

Concentrations of LTB4, LTC4, LTD4 and LTE4 in bronchiolitis due to respiratory syncytial virus

Fifty-five infants with bronchiolitis due to respiratory syncytial virus were evaluated for the presence of leukotriene B₄, C₄, D₄ and E₄ in nasopharyngeal secretions. An attempt was made to correlate concentrations of leukotrienes to arterial oxygen tension. Forty participants received conventional therapy consisting primarily of aerosolized albuterol and occasional aminophylline therapy. The other 15 individuals received ribavirin therapy in addition to conventional therapy, and leukotriene concentrations were compared among individuals in these groups. RSV infection was documented by standard methods, and leukotrienes were measured by reverse-phase high pressure liquid chromatography. The leukotriene detected most commonly was LTC₄ (up to 83% of subjects); LTD₄ and LTB₄ were present in approximately 30% of individuals. The mean partial pressure of oxygen was found to be lower in those individuals with detectable LTB₄ than in those without detectable LTB₄ (p < 0.025), and an overall inverse correlation of LTB₄ concentrations with initial pO₂ values was observed (r = 0.318, p < 0.05). The presence and quantity of other leukotrienes did not correlate with the severity of illness. During the first week of illness, the concentration of leukotrienes declined sharply in ribavirin recipients. Individuals receiving conventional therapy during the same time interval exhibited stable or increasing leukotriene concentrations. These observations suggest that LTB₄ may be important in the pathogenesis of bronchiolitis, and that ribavirin therapy may inhibit leukotriene release in the respiratory tract.     

NeOProM: Neonatal Oxygenation Prospective Meta-analysis Collaboration study protocol

Background  

The appropriate level of oxygenation for extremely preterm neonates (<28 weeks' gestation) to maximise the greatest chance of survival, without incurring significant morbidity, remains unknown. Infants exposed to lower levels of oxygen (targeting oxygen saturations of <90%) in the first weeks of life are at increased risk of death, cerebral palsy, patent ductus arteriosus, pulmonary vascular resistance and apnoea, whilst those maintained in higher levels of oxygen (targeting oxygen saturations of >90%) have been reported to have greater rates of morbidity including retinopathy of prematurity and chronic lung disease. In order to answer this clinical dilemma reliably, large scale trial evidence is needed.     

Altered Na+-K+ ATPase activity in uraemic adolescents

The Na⁺-K⁺ ATPase enzyme plays an essential role in the regulation of cell composition and volume. Enzyme activity itself is regulated by substrate availability and several hormones. In adult uraemic patients red blood cell Na⁺-K⁺ ATPase activity is decreased. However, it is unknown if children with uraemia exhibit the same phenomenon. Therefore, in the present study we examined whether endogenous digoxin-like factors (EDLF) and physicochemical membrane properties play a role in the regulation of erythrocyte Na⁺-K⁺ ATPase activity in uraemic children and adolescents. Healthy age-matched children were used as controls. Enzyme activity was measured in detergent-pretreated red blood cells and erythrocyte ghosts. Na⁺-K⁺ ATPase activity (2204 ± 538nmol Pi ml erythrocyte^?1 h^?1 in detergent pretreated erythrocytes; 204 ± 56 nmol Pi mg protein^?1 h^?1 in ghosts) in adolescents with uraemia was lower compared to controls (3245 ± 362 nmol Pi ml erythrocyte ¹ h^?1; 266 ± 37 nmol Pi mg protein^?1 h^?1, p < 0.001, p < 0.05, respectively). Plasma levels of EDLF were elevated in uraemic patients (0.30 ± 0.05 versus 0.21 ±0.04 ng ml^?1, p < 0.01). Furthermore, the membrane lipid component was decreased in patients with uraemia, while the cholesterol/phospholipid ratio and membrane fluidity were similar in both groups. No correlation was found between the decrease in Na⁺-K⁺ ATPase and the increase in EDLF concentration and altered membrane lipid components. Our results demonstrate, that similar to the findings of adults, the activity of Na⁺-K⁺ ATPase is diminished in uraemic adolescent patients, and that uraemia-associated elevation in EDLF and altered membrane components do not play a role in the down-regulation of Na⁺-K⁺ ATPase. Therefore other factors (presence of other inhibitors and/or reduced number of enzyme molecules) should contribute to the lower activity of the Na⁺-K⁺ pump.     

Cytochrome B558 Component of O-2M Generating Oxidase in the Neutrophils From Patients With Chronic Granulomatous Disease

Cytochrome b₅₅₈ is probably a component of an electron transport chain which is called NADPH oxidase. Cytochrome b₅₅₈ from the neutrophils of two male patients with chronic granulomatous disease (CGD) and their parents was studied. One of the CGD patients had decreased amounts of cytochrome b₅₅₈, The α-band of light absorption of cytochrome b₅₅₈ at 558 nm was found as a trace, and the peak of the γ-band was shifted to 420 nm, whereas the normal γ-band is at 426 nm. Intermediate amounts of cytochrome b₅₅₈ were present in his mother, whereas his father had a normal amount. Another patient had normal peaks of α- and γ-bands of cytochrome b₅₅₈. Thus, abnormalities in NADPH oxidase of the two patients were different.     

BALANCED (2q-; 14q+) TRANSLOCATION

A child presented at 6 years of age with virilization presumed due to maternal progesterone therapy during pregnancy. She was found to have a balanced translocation involving chromosomes 2 and 14.     

Pyrexia after diphtheria/tetanus/pertussis and diphtheria/tetanus vaccines.

The temperatures of 587 children were taken before and after diphtheria/tetanus/pertussis (DTP) or diphtheria/tetanus (DT) vaccine. Only slight temperature increases were found but these were notably more frequent after plain than adsorbed DTP vaccine preparations and the frequency increased with each successive dose.     

Survival of Cr51-labelled Red Cells from New-born Infants1

Summary
The survival of Cr⁵¹-labelled placental red cells of 10 full-term and 6 premature infants was studied after transfusion to adult recpients. The mean apparent half-life of the red cells from full-term infants was found to be 22.8 days, and that of red cells from premature infants 15.8 days (cf. 27.5 days for red cells from adults). Results obtained by others using the differential agglutination method have indicated a longer life span than that corresponding to the Cr⁵¹ half-times above mentioned. The most probable explanation of this difference seems to be that Cr⁵¹ is eluted more rapidly from fetal red cells than from red cells of adults. This hypothesis is corroborated by the results of experiments in vitro on intact red cells.