Early computed tomographic scanning after resection of brain tumors in children

Enhanced and non-enhanced computed tomography (CT) brain scans were performed within 72 h of surgery on 21 children in whom brain tumors had been resected totally or subtotally, and scans were repeated at varying intervals thereafter. Biopsies of the resection margins were performed in 12 patients at the end of the surgical procedure. The immediate CT scan showed enhancement in the resection margin in 13 of the 21 patients and in 9 of the 13, the enhancement disappeared on follow-up scans. There was discordance between the results of immediate CT scan examination and the biopsies of the resection margins in 7 of the 12 cases. The advantages and disadvantages of an immediate postoperative scan versus a more delayed CT scan are discussed.     

Inflammatory regulation of extracellular matrix remodeling in calcific aortic valve stenosis.

BACKGROUND: Calcific aortic stenosis (AS), the most frequent heart valve disorder in developed countries, leads to the calcification and fibrous thickening of the valve. While several studies have addressed the process of valvular calcification, the molecular pathomechanisms of the extensive matrix remodeling remain unclear. Because inflammation is present in stenotic valves, we hypothesized that the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) might influence cell proliferation and regulate the expression and activation of matrix metalloproteinases (MMPs)--enzymes that are thought to be involved in calcific AS. METHODS: Immunohistochemistry for leukocytes, TNFalpha, MMP-1, and the endogenous MMP inhibitor tissue inhibitor of metalloproteinase (TIMP)-1 was performed on human stenotic (n = 19) and control (n = 8) valves. Primary cultures of human aortic valve myofibroblasts were incubated with and without TNFalpha, and cell proliferation was assessed. The expression and activation of MMP-1 were detected by Western blotting and a specific MMP-1 activity assay. RESULTS: Control valves showed scattered macrophages and low expression of TNFalpha, MMP-1, and TIMP-1. In stenotic valves, leukocyte infiltration and a strong, colocalized expression of TNFalpha and MMP-1 were present, while TIMP-1 remained unchanged. Double-label immunofluorescence localized TNFalpha mainly to macrophages. In cultured human aortic valve myofibroblasts, TNFalpha stimulated proliferation and induced a time-dependent increase in MMP-1 expression and activation, while TIMP-1 remained unchanged. CONCLUSION: The results indicate that matrix remodeling in calcific AS involves the expression and activation of MMPs. Activated leukocytes, by the secretion of TNFalpha, may stimulate valvular myofibroblasts to proliferate and express MMPs, thus regulating actively the matrix remodeling in calcific AS.     

Susceptibility to beta-lactam antibiotics and production of beta-lactamase inBacteroides fragilis

Using the agar dilution technique, 231 strains of Bacteroides fragilis, isolated during a 2-year period from human infections, were identified at subspecies level and were tested for susceptibility to 13 beta-lactam antibiotics. The penicillins were benzylpenicillin, ampicillin, carbenicillin, cloxacillin, and the recently described penicillin derivatives cyclacillin, ticarcillin, and PC-904. The following cephalosporin derivatives were tested: cephaloridine, cephalothin, cephalexin, cefamandole and cefuroxime. The cephamycin C derivative cefoxitin was also included in the study. Cefoxitin was the most effective drug tested since more than 80% of the strains were inhibited by 8 microgram/ml or less, and no strain had a minimal inhibitory concentration (MIC) of more than 64 microgram/ml. There was no marked difference in sensitivity among the subspecies with exception of subspecies vulgatus, which was slightly more sensitive to all antibiotics tested. The size of the inoculum was an important factor for obtaining reproducible results in the sensitivity tests. Increased inocula resulted in markedly higher MICs for cephaloridine and cefuroxime. Production of beta-lactamase was performed on all isolates by a chromogenic cephalosporin substrate and about 90% of the strains were found to be beta-lactamase producers.     

Expression of bone sialoprotein and bone morphogenetic protein-2 in calcific aortic stenosis

BACKGROUND AND AIM OF THE STUDY: Calcific aortic stenosis, the major heart valve disease encountered in the elderly, leads to massive calcium deposition in the valve leaflets that morphologically resembles bone formation. Recent studies have demonstrated the expression of various bone-associated proteins in stenotic valves, suggesting that valvular calcification may be an actively regulated process. Bone sialoprotein (BSP), a non-collagenous bone matrix protein, and bone morphogenetic protein-2 (BMP-2), a member of the transforming growth factor cytokine superfamily, are known to participate in the regulation of bone development and maturation. Their pathogenetic role in calcific aortic stenosis is unknown. METHODS: Using an immunoperoxidase technique and antibodies against BSP and BMP-2, the expression of BSP and BMP-2 was examined in 16 human aortic valves with calcific aortic stenosis obtained at valve replacement, and in seven normal autopsy controls without signs of aortic stenosis. RESULTS: By semiquantitative scoring, stenotic valves showed a significantly increased staining of BSP in cells and extracellular matrix as compared to control valves (2.7 +/- 0.1 versus 0.6 +/- 0.2 score units, p <0.001). Marked BMP-2 expression was detected in stenotic valves, mostly in cell-rich areas associated with focal calcium deposits, but no specific staining for BMP-2 was detected in control valves (1.5 +/- 0.2 versus 0.0 +/- 0.0 score units, p <0.001). CONCLUSION: These results demonstrate for the first time that BSP and BMP-2 are differentially expressed in normal aortic valves and in aortic stenosis, thereby supporting the concept that valvular calcification might be based on an actively regulated process involving BSP and BMP-2.     

Apolipoproteins A-I and B in obese children

Body mass index (BMI), the distribution of fat, birth weight, physical fitness, apolipoproteins (apo) A-I and B, total cholesterol (TC), and high-density lipoprotein cholesterol (HDLC) were studied in 38 obese 10- to 11-year-olds in comparison to 52 age-matched controls. Obese children had higher concentration of apo B and a lower apo A-I:B ratio. Significant correlations were found between (a) apo A-I and physical fitness (r = 0.35, p less than 0.015), triceps skinfold thickness (r = 0.44, p less than 0.01), and birth weight (r = -0.33, p less than 0.05); (b) physical fitness and triceps skinfold thickness (r = 0.38, p less than 0.05), and (c) the apo A-I:B ratio and triceps skinfold thickness (r = 0.31, p less than 0.05). When both obese and control children were grouped together, a correlation was found between BMI and TC (r = 0.24, p less than 0.05), apo B (r = 0.37, p less than 0.001), and the apo A-I:B ratio (r = -0.31, p less than 0.01). Multiple regression analyses indicated a significant positive contribution to the apo A-I level by HDLC and physical fitness and a negative one by birth weight.     

Electrophysiologic studies, computed tomography, and neurologic outcome in acute bacterial meningitis

To determine the value of computed tomography and electrophysiologic studies in predicting neurologic outcome, we prospectively studied 41 children with acute bacterial meningitis, using clinical examination, computed tomography of the head, electroencephalography, brain-stem auditory evoked response, and visual evoked potential mapping during the acute illness. Two children died; 32 of the remaining 39 children were reviewed clinically, electrophysiologically, and with computed tomography between 5 and 38 months after the illness. The electrophysiologic data obtained during the illness were not found to alter the acute-stage management. Focal or generalized suppression, demonstrated on the electroencephalogram, was associated with a poor outcome. Cerebral infarction and edema, demonstrated by computed tomography of the head, were predictive of a poor outcome, but enlarged ventricular and subarachnoid spaces and increased subdural effusions were of no predictive value. Neither computed tomographic scans nor electrophysiologic data were better indicators of neurologic prognosis than the clinical examination.