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Biomedical subjects

G Presbury

Publications and source records attributed to G Presbury.

8 recordsLinked to original sources

Penicillin- and cephalosporin-resistant strains of Streptococcus pneumoniae causing sepsis and meningitis in children with sickle cell disease.

OBJECTIVE: We investigated the possibility that antimicrobial-resistant pneumococci were causing invasive disease in children with sickle-cell disease (SCD). STUDY DESIGN: Records of all children with SCD observed at the Mid-South Sickle Cell Center (MSSCC) at LeBonheur Children's Medical Center were reviewed from January 1990 to June 1994. Children with SCD and pneumococcal sepsis were identified. The Streptococcus pneumoniae isolates from these children were examined for serotype and antimicrobial susceptibilities. Two additional children not observed in the MSSCC had pneumococcal sepsis caused by penicillin-resistant isolates and were also included. RESULTS: Antimicrobial susceptibility testing of the six penicillin-resistant isolates revealed that four were resistant to trimethoprim-sulfamethoxazole, two to erythromycin, and one to clindamycin. The two isolates that were resistant to ceftriaxone also were multiply resistant. From the MSSCC, 26 children had pneumococcal sepsis during the 4 1/2-year period studied. Five of these children (19%) died. Four (15%), including one who died, were infected with penicillin-resistant strains. CONCLUSION: Pneumococcal sepsis, meningitis, and infections of other foci in children with SCD may be caused by S. pneumoniae that is resistant to one or more antimicrobial agents, including penicillin. The addition of vancomycin to the antibiotics currently used for initial management should be considered in areas where the antibiotic resistance of S. pneumoniae is prevalent.

Anemia, Sickle Cell

Auditory function in sickle cell anemia.

Auditory acuity and central auditory processing were assessed in 22 patients with sickle cell anemia, 13 of whom were chronically transfused, and compared with a control black population. Pure tone air conduction thresholds were within normal limits for all patients, and mean Speech Reception Threshold for each ear was normal at 10 dB. All subjects exhibited type A tympanograms. Central auditory processing was assessed by the Competing Sentence Test and Binaural Fusion Test. No significant differences were found among transfused, nontransfused, and control patients. Abnormal auditory function does not appear to be a common problem in patients with sickle cell disease.

Adolescent

Prophylaxis with oral penicillin in children with sickle cell anemia. A randomized trial.

Children with sickle cell anemia have an increased susceptibility to bacterial infections, especially to those caused by Streptococcus pneumoniae. We therefore conducted a multicenter, randomized, double-blind, placebo-controlled clinical trial to test whether the regular, daily administration of oral penicillin would reduce the incidence of documented septicemia due to S.pneumoniae in children with sickle cell anemia who were under the age of three years at the time of entry. The children were randomly assigned to receive either 125 mg of penicillin V potassium (105 children) or placebo (110 children) twice daily. The trial was terminated 8 months early, after an average of 15 months of follow-up, when an 84 percent reduction in the incidence of infection was observed in the group treated with penicillin, as compared with the group given placebo (13 of 110 patients vs. 2 of 105; P = 0.0025), with no deaths from pneumococcal septicemia occurring in the penicillin group but three deaths from the infection occurring in the placebo group. On the basis of these results, we conclude that children should be screened in the neonatal period for sickle cell hemoglobinopathy and that those with sickle cell anemia should receive prophylactic therapy with oral penicillin by four months of age to decrease the morbidity and mortality associated with pneumococcal septicemia.

Administration, Oral

Lymphocyte phenotype and function in chronically transfused children with sickle cell disease.

Immunologic studies were performed on mononuclear cells from ten chronically transfused children with sickle cell disease, and the results were compared with those from five other groups: 21 sickle cell patients who were not receiving regular transfusions, 6 chronically transfused children with other forms of refractory anemia, 10 previously splenectomized children, 5 boys with hemophilia A, and 27 normal adult controls. The helper:suppressor T cell ratios (T4:T8) in all groups except hemophiliacs were normal, were unrelated to the number of units transfused, and were not suggestive of findings reported for patients with the acquired immune deficiency syndrome (AIDS) or groups at risk for the syndrome. Percentages of T3, T4, and T8 cells were low in sickle cell and splenectomized patients, but not in chronically transfused patients with other anemias. Serum IgG was frequently elevated, and IgG synthesis in vitro was increased relative to IgM synthesis in sickle cell patients. Coculture experiments indicated that such findings may stem from a selective increase in IgG synthesis by B cells. Thus, transfused sickle cell patients have a particular pattern of immunologic abnormalities that is distinct from that seen in AIDS.

Acquired Immunodeficiency Syndrome

Hemothorax and hemomediastinum in patients with hemophilia.

Three patients with hemophilia presented with hemothoraces which resolved within 1-3 weeks following treatment with factor concentrates. Drainage of blood was not necessary. Eight previously reported cases are reviewed, and therapy and complications are summarized. We suggest that treatment of this rare complication of hemophilia with factor concentrates and avoidance of surgical intervention is indicated.

Adolescent

Immunoregulatory abnormalities in Evans syndrome.

Immune function in six patients with Evans syndrome (Coombs-positive hemolytic anemia and immune thrombocytopenia) was compared to that in seven with chronic ITP. The two groups differed in measurements of T-cell subsets and immunoglobulin production. Evans syndrome patients had decreased T4 (T-helper) (P = 0.025), increased T8 (T-suppressor) (P = 0.008), and a decreased ratio of T4:T8 cells (P = 0.0009) when compared to controls. Results in chronic ITP patients were similar to those in controls. Serum IgG, IgM, and IgA levels and in vitro synthesis of IgG and/or IgM were decreased in most Evans syndrome patients. Diminished in vivo and in vitro immunoglobulin synthesis in Evans syndrome is consistent with the decreased T4:T8 ratio in these patients. The altered T4:T8 ratio may represent an unsuccessful response to an autoimmune process in which the trigger is unknown.

Adolescent