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Biomedical subjects

D Stevens

Publications and source records attributed to D Stevens.

At least 109 records · Page 6Linked to original sources
PubMed1979

Folic acid supplementation in low birth weight infants.

Low birth weight infants (246) entered a trial to folic acid supplementation from 3 weeks to 12 months of age. The folic acid group had significantly higher mean hemoglobin levels at 6 and 9 months of age but the differences were only about 0.5 gm/dl, there was no significant difference in hematocrit, and in both groups of infants the mean hemoglobin levels were higher than those of normal birth weight infants. The differences in hemoglobin, although statistically significant, are of uncertain clinical significance. Median red cell folate levels remained within the normal adult range in both groups of infants. A minority of infants in the untreated group had low red cell folate levels but this was usually temporary, corrected by dietary folate, and not associated with low hemoglobin. Weight gain was not affected by folic acid supplementation. The infants in this trial were fed with a milk preparation containing 3.5 microgram/100 ml of folic acid which is a similar concentration to that of human milk and we recommend that the folate content of milks fed to low birth weight infants should not fall below this level. We do not have sufficient grounds to recommend routine folic acid supplements for all low birth weight infants throughout the first year of life but there is a possibility that their folate intake may sometimes be suboptimal.

Anemia, Macrocytic↗
PubMed1978

Mycoplasma pneumoniae infections in children.

Details are given of all serologically confirmed Mycoplasma pneumoniae infections in children referred to Bristol hospitals during an epidemic lasting 18 months. 44 children, many below school age, had lower respiratory infections. The majority had cough and malaise which had failed to respond to antibiotics given before referral. Chest x-rays showed no pathognomonic features: segmental or patchy consolidation was common; 3 cases of lobar consolidation. Cold agglutinins were raised in 9 out of 12 cases. In the majority of cases the total leucocyte count was normal and the absolute neutrophil count raised. Mean duration of symptoms was 4.2 weeks (range 1-16). Treatment with erythromycin or tetracycline appeared to have little effect in most cases. Seven nonrespiratory manifestations were seen in 6 children. These were meningitis (2 cases), Stevens-Johnson syndrome (4 cases, 1 case complicated by toxic epidermal necrolysis), and acute haemolytic anaemia (1 case).

Adolescent↗
PubMed1977

Characteristics of the immune response in a patient with Whipple's disease.

A patient with Whipple's disease has been studied to examine the effect of antibiotic therapy on the immune status of the patient, and the specific immune response to a cell wall deficient form of an alpha-haemolytic streptococcus (alpha HS) isolated from this patient. T lymphocyte numbers were reduced, and cutaneous anergy was present. Autoantibodies directed against smooth muscle and mitochondria were detected. These abnormal parameters became normal following antibiotic therapy. The specific immune response to the alphaHS was characterised by IgA antibody and lymphocyte sensitisation. The latter was detected as antigen-inducedd lymphocyte stimulation and antigen-induced leucocyte inhibition factor (LIF) production. Antibiotic therapy was associated with a fall in antibody titre and reduced LIF production. No defect in neutrophil function was found. These results are most consistent with the postulates that (i) immunological abnormalities in Whipple's disease are secondary to infection and (ii) the primary abnormality is an unusual pathogenic bacterium.

Adult↗
PubMed1972

Synthesis and turnover of nitrate reductase in corn roots.

THE INDUCTION AND REINDUCTION OF NITRATE REDUCTASE IN ROOT TIP OR MATURE ROOT SECTIONS SHOW ESSENTIALLY A SIMILAR PATTERN: a lag, a period of rapid increase in enzyme activity and finally a period of relatively minor change. Both inductions are sensitive to 6-methylpurine and cycloheximide. Kinetic studies with 6-methylpurine suggest that the half-life of the messenger RNA for nitrate reductase in both sections is about 20 minutes. The rate of decay of nitrate reductase activity induced by transfer to a nitrate-free medium is slower in root tips (t(1/2) = 3 hours) than in mature root sections (t(1/2) = 2 hours). The enzyme from mature root sections is also less stable to mild heat treatments (27 C; 40 C) than the enzyme from root tip sections. The results indicate that factors regulating enzyme turnover show important changes as root cells mature and may be significant in determining steady state levels of the enzyme.

Journal Article↗