Developmental regulation of annexin II (Lipocortin 2) in human brain and expression in high grade glioma.

In experiments to identify molecules that might be important in the pathogenesis of glioblastoma multiforme, the most common malignant brain tumor, we found that annexin II (Lipocortin 2, p36), a likely second messenger in several different mitogenic pathways, was highly expressed in tumor tissue of glioblastoma multiforme (9 of 9) and highly anaplastic astrocytoma (2 of 6), but not in astrocytomas of lower pathological grade (0 of 6). We also detected high levels of annexin II expression in fetal brain during the period when radial glia proliferate, although annexin II expression was not detected in normal adult brain. These data demonstrate that annexin II expression is developmentally regulated in the human central nervous system and suggest that the early progenitor radial glia share important characteristics with highly malignant glial tumors.     

Microbiologically proven bacterial infections in AIDS.

We have reviewed the incidence, type and site of microbiologically proven bacterial infection occurring in 52 patients with the acquired immunodeficiency syndrome (AIDS) who presented to Southmead Hospital, Bristol between 1990 and 1994. A total of 30 (58%) patients had significant bacterial isolates. The majority of infections were community acquired. Overall, more infections were caused by Gram-negative organisms but Gram-positive organisms predominated in bacteraemia. Mycobacterium avium intracellulare (MAI) caused infection in the largest number of patients, followed by Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas sp, and Campylobacter sp. When individual episodes of infection were considered, after MAI, Haemophilus influenzae, Streptococcus pneumoniae and Pseudomonas sp were the organisms most frequently isolated; often these same organisms caused recurrent chest infection. Bacterial infections in AIDS patients are common and although they generally respond well to antimicrobial chemotherapy there is a high recurrence rate, particularly in the respiratory tract, which is the commonest site of infection.     

Effect of inoculum size and medium on activity of seven antimicrobial agents against Bacteroides fragilis strains

Antimicrobial activity of cefoxitin, cefotetan, cefotaxime, ceftizoxime, ceftazidime, imipenem, and clindamycin against four inocula of Bacteroides fragilis strains was determined on three different media. The inoculum sizes were 10(4), 10(5), 10(6), and 10(7) colony forming units (CFU) per spot. On all three media, substantial effects of inoculum size on minimal inhibitory concentrations (MIC) of cefotaxime and ceftizoxime were found: the doubled dilution differences in MICs between inocula of 10(7) and 10(4) CFU/spot were 2.2, 2.3, and 2.1 micrograms/ml of cefotaxime and 1.8, 4.4, and 4.0 micrograms/ml of ceftizoxime on Brucella base-laked blood agar, Wilkins-Chalgren agar, and a brain-heart infusion medium, respectively. An inoculum difference found on all three media with ceftazidime may also be of practical significance. There was evidence of larger differences between inocula on the Wilkins-Chalgren agar and brain-heart infusion than on the Brucella agar.     

Electroretinograms (ERGs) and visual-evoked potentials (VEPs) elicited by pattern displacement.

The relation between the amplitude of visual responses to a checkerboard stimulus and the degree of lateral displacement of the checks was examined across different check sizes with simultaneously recorded electroretinograms (ERGs) and visual-evoked potentials (VEPs). The amplitudes of both the b-wave and the after-potential of the ERG increase linearly with pattern displacement. However, the major components of the VEP (N70 and P100) were smaller than expected from linearity for both small checks with small displacements (thresholding) and for large checks with large displacements (saturation). These results suggest that the ERG is proportional to the number of receptors stimulated, but the VEP reflects neural processes influenced by the spatial structure of the stimulus.