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Biomedical subjects

B L Wiedermann

Publications and source records attributed to B L Wiedermann.

31 records · Page 2Linked to original sources
PubMed1989

Aztreonam in the treatment of gram-negative meningitis and other gram-negative infections.

Ninety patients (41 males, 49 females) with a diagnosis of meningitis, urinary tract infection (UTI), gastroenteritis or other miscellaneous gram-negative infections were enrolled. Their ages ranged from 7 days to 10 years, with a mean age of 4 months. 58 (63%) patients had an etiology confirmed by either positive culture (52; 89%) or latex agglutination (6; 10%). 41 of these patients had meningitis diagnosed by positive CSE culture (38) or by positive CSF latex agglutination (3); 27/41 patients also had positive blood cultures. Aztreonam MIC100 for 27 isolates of Haemophilus influenzae, all ampicillin-sensitive, was 0.19 micrograms/ml; 4 Salmonella sp., 1 Neisseria meningitidis and 1 Serratia marcescens isolates were inhibited by 0.19 micrograms/ml, and the MIC100 for 2 Klebsiella pneumoniae, 1 Proteus vulgaris and 2 Pseudomonas aeruginosa isolates were 0.045 and 0.19, 0.022 and 12.5 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aztreonam↗
PubMed1988

Treatment of intracranial abscesses associated with sinusitis in children and adolescents.

We retrospectively reviewed the management of intracranial abscesses associated with sinusitis in 13 children and adolescents by reviewing medical records and computed tomography (CT) scans of a consecutive case series. The mean duration of follow-up was 4.5 years with a range of 1.3 to 8.6 years, and the setting was a major metropolitan children's hospital providing primary as well as tertiary care. All patients received antibiotics (most commonly chloramphenicol, 75 to 100 mg/kg/day, in combination with oxacillin, 150 to 200 mg/kg/day) to which the sinus and intracranial organisms are susceptible. Surgical drainage of loculated infection was done for patients with acute neurologic symptoms or signs and for those patients whose abscesses enlarged during medical therapy. Three patients underwent immediate drainage of intracranial abscesses because of acute neurologic signs and symptoms. Sequential CT scans demonstrated enlargement of the intracranial abscesses in the remaining 10 patients. This apparent failure of medical management could not be explained by duration of symptoms before therapy, size of lesion, choice of antibiotics, or use of steroids. No child was successfully treated with antibiotics alone. Successful management consisted of antibiotic therapy combined with surgical drainage of loculated infection. This approach to therapy is preferred for all children with intracranial abscess associated with sinusitis.

Adolescent↗
PubMed1986

Pathogenesis of labyrinthitis associated with Haemophilus influenzae type b meningitis in infant rats.

The pathogenesis of labyrinthitis associated with bacterial meningitis was studied by histopathologic examination of inner ears of 114 rats with Haemophilus influenzae type b meningitis produced by ip inoculation of one of 13 clinical isolates. Findings consisted of inflammation of the perilymphatic spaces of the cochlea and semicircular canals with sparing of the endolymphatic space, cochlear nerve fibers, and middle ear. The degree of inflammation peaked at 48 hr after inoculation, then declined by 96 to 144 hr. No interstrain differences in type or degree of pathology were observed. Immunofluorescent staining of cochleae from 15 animals demonstrated that bacteria were present in areas of inflammation and also in the endolymphatic space and organ of Corti. One isolate displayed a tendency to accumulate in the perilymphatic spaces in larger numbers than those seen with three other isolates. These findings suggest that, in this model, inflammation reaches the inner ear by spreading from the subarachnoid space. Bacterial invasion of the organ of Corti may be one mechanism by which deafness occurs in bacterial meningitis.

Animals↗
PubMed1985

Frequency and properties of naturally occurring adherent piliated strains of Haemophilus influenzae type b.

We found that 41 of 75 (55%) children with Haemophilus influenzae type b disease (70 cases of meningitis, 2 of cellulitis, 2 of septic arthritis, and 1 of epiglottitis) and 2 of 120 (1.7%) children with upper respiratory infection were colonized with H. influenzae type b in the nasopharynx (NP). Of these 43 NP strains from children with systemic H. influenzae type b disease, 7 (16%) adhered to human buccal epithelial cells. The strains isolated from the systemic site of all children, including children from whose NP adherent bacteria were isolated, did not adhere to buccal epithelial cells in vitro. Each adherent NP strain had biotype (I), serotype (b), and antibiotic susceptibility (sensitive) similar to that of the corresponding nonadherent systemic isolate. With one exception, all NP-systemic pairs had similar major outer membrane proteins. Six of the seven NP strains had a protein band in the whole cell lysate preparation with a molecular weight between 22,000 and 23,000, which could not be seen in the nonadherent cerebrospinal fluid strains. Electron micrographs of all adherent strains showed that more than 95% of the organisms examined were highly piliated, whereas the nonadherent strains were not piliated. All piliated strains agglutinated human erythrocytes. Adherence to buccal epithelial cells and agglutination of erythrocytes could not be blocked by mannose or alpha-methyl-D-mannoside. We speculate that piliation is not important for NP colonization by H. influenzae type b and that the loss of pili may be required for host invasion.

Adhesiveness↗
PubMed1983

Role of adherence in the pathogenesis of Haemophilus influenzae type b infection in infant rats.

We evaluated the role of pili in the pathogenesis of disease due to Haemophilus influenzae type b (HiTb), using the infant rat model. Piliated and nonpiliated HiTb strains were isolated from the nasopharynx and cerebrospinal fluid, respectively, of three children. Infant rats inoculated intranasally with nonadherent HiTb developed bacteremia and meningitis more frequently (P = 0.005) than animals inoculated with companion adherent HiTb strains. When analyzed separately, only one HiTb pair (884/880) demonstrated significant differences in the incidence of bacteremia and meningitis between the adherent and nonadherent strains. Blood or cerebrospinal isolates recovered from infant rats inoculated with piliated adherent HiTb strains were not piliated and were not adherent in vitro. Adherent and nonadherent HiTb colonized the nasopharynx of infant rats equally. The piliated strains of HiTb were not adherent in vivo or in vitro to rat nasal or buccal epithelial cells, respectively. Piliated strains of HiTb have no apparent advantage over nonpiliated HiTb strains for colonization or invasion of infant rats. Furthermore, the loss of piliation is noted for cerebrospinal fluid, blood, and nasal isolates of HiTb cultured from infant rats inoculated with an adherent piliated HiTb strain. Thus, the loss or suppression of pili may be an important prerequisite for the invasion of the host by HiTb strains that are highly piliated.

Animals↗
PubMed1975

Acceleration of tetramer formation by the binding of inositol hexaphosphate to hemoglobin dimers.

The aggregation of deoxyhemoglobin dimers was studied by dropping the pH of a dilute solution of deoxyhemoglobin originally at high pH. In the presence of inositol hexaphosphate, a sharp increase in the rate of dimer association was observed. At higher concentrations of the phosphate, the rate decreased to a value close to that seen in the absence of phosphate. These observations require that inositol hexaphosphate binds to deoxyhemoglobin dimers. The dependence of the aggregation rate on phosphate concentration occurs because the reaction of a dimer containing bound phosphate with a phosphate-free dimer is 30 to 50 times faster than either the association of phosphate-free dimers or the association of dimers both containing bound phosphate.

Hemoglobins↗
PubMedDate not supplied

Experience with rapid latex agglutination testing for group A streptococcal pharyngitis in a pediatric group office laboratory.

We evaluated 2401 patients with suspected streptococcal pharyngitis with the Culturette 10-minute Group A Strep ID test during a 6-month period in order to determine its suitability for rapid diagnosis in a busy private office practice. Duplicate throat swabs were obtained for each child, and latex agglutination was performed within 15 minutes. In children with negative latex agglutination results, the second swab was cultured. All latex agglutination results were available within 20 minutes of collection, while the patients waited in the office. Seven hundred thirty-eight specimens were positive by latex agglutination. Seventy-eight of the 1663 latex negative specimens contained group A streptococci on culture (sensitivity 90 percent). Approximately 60 percent of these latex-negative, culture-positive specimens demonstrated 3(+)-4+ growth in culture, unlike previous studies ascribing false-negative latex results to low colony count specimens. Fifty percent of bacitracin-susceptible streptococci tested were not group A, indicating a relatively high occurrence of nongroup A beta-hemolytic streptococcal carriage in this patient population. The use of latex agglutination for detection of group A streptococcal pharyngitis was well-suited to our office practice, even during an extremely busy winter season. Although this assay appears to have a relatively high sensitivity, it is still prudent to culture latex-negative swabs to exclude group A streptococcal infection. The significance of nongroup A beta-hemolytic streptococci in our patient population was unclear. Further refinements are necessary.

Child↗