Phase-contrast MRI measurement of systolic cerebrospinal fluid peak velocity (CSFV(peak)) in the aqueduct of Sylvius: a noninvasive tool for measurement of cerebral capacity.
(17/1631)
BACKGROUND: Cerebrospinal fluid (CSF) outflow to intra- and extracranial subarachnoid spaces caused by arterial inflow to the brain predominantly compensates systolic increases in cerebral blood volume. Phase-contrast magnetic resonance imaging is a new tool for noninvasive assessment of CSF displacement by measuring CSF peak velocity (CSFV(Peak)). The authors tested this new tool in an experimental human model of increased intracranial pressure and reduced cerebral capacity by means of continuous positive airway pressure (CPAP) breathing. METHODS: The authors investigated systolic CSFV(Peak) in the aqueduct of Sylvius in 11 awake, normocapnic (end-tidal carbon dioxide [ET(CO2)] = 40 mmHg) volunteers without CPAP and at two different CPAP levels (6 and 12 cm H2O) by means of electroencephalography-gated phase-contrast magnetic resonance imaging. RESULTS: Administration of 6 cm H2O CPAP did not change systolic CSFV(Peak) (-4.9+/-2.8 cm/s vs. control: -5.1+/-2.7 cm/s), whereas 12 cm H2O CPAP significantly reduced systolic CSFV(Peak) (-4.0+/-1.8 cm/s vs. control: -5.1+/-2.7 cm/s; P < 0.05). CONCLUSIONS: These findings in awake volunteers show that monitoring CSFV(Peak) in the aqueduct of Sylvius is a sensitive method for detecting even minor impairment of cerebral capacity caused by experimentally induced increases in intracranial pressure. (+info)
Improved methods for immunoassay of mycothiol.
(18/1631)
Improved enzyme-linked immunosorbent assay (ELISA) methods have been developed for the determination of femtomole amounts of mycothiol (MSH), the main low-molecular-weight thiol in mycobacteria. The immunoassays utilize an affinity-purified rabbit polyclonal antibody that is highly specific for the pseudodisaccharide moiety of MSH. MSH was first biotinylated by the thiol-specific reagent 3-(N-maleimidopropionyl)biocytin. The MSH-biotin adduct was then captured with immobilized avidin and detected with anti-MSH antibody (biotin-capture ELISA) or was captured with immobilized anti-MSH antibody and detected with alkaline phosphatase-labelled avidin (MSH-capture ELISA). The MSH-capture ELISA was the most sensitive method, measuring as little as 0.3 fmol of MSH. Methods for biotinylating MSH directly from Mycobacterium spp. are described. The MSH-capture ELISA was tested for the detection of M. avium seeded in human urine or cerebrospinal fluid samples and for screening mutant M. smegmatis strains to detect MSH production. (+info)
High-resolution MR cisternography of the cerebellopontine angle: 2D versus 3D fast spin-echo sequences.
(19/1631)
BACKGROUND AND PURPOSE: The clinical usefulness of MR cisternography of the cerebellopontine angle, applying 2D or 3D fast spin-echo sequences, has been reported recently. Our purpose was to investigate the cause of signal loss in CSF in the prepontine or cerebellopontine angle cistern on 2D FSE MR images and to compare the cisternographic effects of 2D and 3D FSE sequences. METHODS: Preliminary experiments were performed in four volunteers to assess the causes of signal loss. Initially, using a 2D cardiac-gated cine phase-contrast method with a velocity encoding value of 6 cm/s, we measured the velocity and flow pattern of CSF. Comparisons were made to assess the effects of intravoxel dephasing, amplitude of the section-selecting gradient, echo time (TE), and section thickness. Four healthy subjects and 13 patients with ear symptoms were examined, and multisection 3-mm-thick 2D images and 30-mm-slab, 1-mm-section 3D images were compared qualitatively and quantitatively. Then, 3D MR cisternography was performed in 400 patients with ear symptoms, and qualitative evaluation was performed. RESULTS: In volunteers, the average peak velocity of CSF was 1.2 cm/s. With TE = 250, CSF may move an average of 3 mm, and can be washed out of a 3-mm-thick 2D section volume. The CSF signal relative to that of a water phantom decreased gradually as TE increased on single-section 3-mm-thick 2D images. The CSF signal relative to that of the water phantom increased gradually as section thickness increased. No significant differences were noted in intravoxel dephasing and amplitude of the section-selecting gradient. The contrast-to-noise ratio (CNR) between CSF and the cerebellar peduncle, and the visibility of the cranial nerves and vertebrobasilar artery were significantly improved on 3D images in 17 subjects. In images from 400 patients, no significant signal loss in the cistern was observed using 3D FSE. CONCLUSION: CSF signal loss in thin-section 2D MR cisternography is mainly attributable to the wash-out phenomenon. 3D acquisition can reduce this phenomenon and provide thinner sections. The scan time for 3D acquisition is not excessive when a long echo train length and half-Fourier imaging are used. MR cisternography should be performed using a 3D acquisition. (+info)
Pharmacodynamics of trovafloxacin in experimental pneumococcal meningitis: basis for dosage selection in children with meningitis.
(20/1631)
Trovafloxacin is a recently approved fluoroquinolone with excellent activity against gram-positive and gram-negative organisms that offers a potential alternative for treatment of beta-lactam-resistant pneumococcal meningitis. Using the rabbit meningitis model, we sought to characterize the pharmacodynamic properties of trovafloxacin in the cerebrospinal fluid (CSF). Animals were given single doses of trovafloxacin of 10, 15, 20 or 30 mg/kg; 1 h after Infusion mean CSF concentrations were 0.59+/-0.18, 0.74+/-0.14, 1.12+/-0.12 and 1.07+/-0.35 mg/L, respectively. The bacterial killing rate Increased with increasing dosages of trovafloxacin, indicating that its activity is concentration dependent. All three pharmacodynamic Indices (area under the concentration curve (AUC)/MBC, peak concentration (Cmax)/MBC, and time above MBC (T > MBC)) correlated with bacterial killing; however, AUC/MBC correlated best (r = 0.71). In a second experiment we found comparable bacterial killing with multiple doses of trovafloxacin given either every serum half-life or every two serum half-lives. In both experiments bacterial regrowth occurred when the concentration of trovafloxacin in CSF fell below the MBC. These data have been used in formulating an appropriate regimen for trovafloxacin treatment of bacterial meningitis in children. (+info)
Meningitis caused by Neisseria meningitidis serogroup 135.
(21/1631)
The first descriptions of meningitis in childhood caused by Neisseria meningitidis serogroup 135 are presented. Difficulties with identification of unusual serogroups of N. meningitidis are discussed. (+info)
Predominance of Vgamma9/Vdelta2 T lymphocytes in the cerebrospinal fluid of children with tuberculous meningitis: reversal after chemotherapy.
(22/1631)
BACKGROUND: We analyzed the gammadelta T cell composition and responses in the peripheral blood and cerebrospinal fluid (CSF) of children affected by tuberculous meningitis (TBM) and in control children. MATERIALS AND METHODS: Peripheral blood and CSF samples were stimulated with different phosphoantigens and IL-2, and expansion of Vgamma9/Vdelta2 T cells assessed by FACS analysis. Vgamma9/Vdelta2 lines were obtained by culturing CSF or peripheral blood mononuclear cells (PBMC) in vitro with phosphoantigens and IL-2 for 2 months, and tested for proliferation and cytokine production in response to phosphoantigens. Vdelta2(D)Jdelta junctional sequence length was assessed by PCR. RESULTS: The repertoire of gammadelta T cells from the CSF of TBM patients was characterized by the predominance of Vgamma9/Vdelta2 T lymphocytes, which accounted for >80% of gammadelta T cells. Vgamma9/Vdelta2 cells from the CSF of TBM children responded to different synthetic and natural (mycobacterial) phosphoantigens and produced discrete amounts of IFN-gamma and TNF-alpha. The in vitro expansion of Vgamma9/Vdelta2 T cells from CSF and peripheral blood of TBM patients prominently decreased following chemotherapy, and similarly, the proportion of ex vivo unstimulated Vgamma9/Vdelta2 T cells in CSF of TBM patients decreased to levels detected in the CSF of control subjects. Vdelta2 CDR3 TCR analysis showed that the remaining Vdelta2 cells in the CSF of TBM patients were still polyclonal. CONCLUSIONS: These findings are consistent with an involvement of Vgamma9/Vdelta2 T cells in TBM. http://link. springer-ny.com/link/service/journals/00020/bibs/5n5p301. html (+info)
Successful treatment of Lyme encephalopathy with intravenous ceftriaxone.
(23/1631)
The efficacy of intravenous ceftriaxone, 2 g per day for 30 days, was evaluated in a case series of 18 consecutive patients who met strict criteria for Lyme encephalopathy. Months to years after classic manifestations of Lyme disease, the 18 patients presented with memory difficulty, minor depression, somnolence, or headache. Sixteen (89%) had abnormal memory scores; 16 (89%) had cerebrospinal fluid (CSF) abnormalities, and all 7 patients tested had frontotemporal perfusion defects on single photon emission computed tomographic (SPECT) imaging. Six months after treatment, memory scores in the 15 patients who completed the study according to protocol were significantly improved (P<.01). In the 10 patients who had follow-up CSF analyses, total protein levels were significantly lower (P<.05). In the 7 patients who had SPECT imaging, posttreatment perfusion was significantly better (P<.01). Twelve to 24 months after treatment, all 18 patients rated themselves as back to normal or improved. We conclude that Lyme encephalopathy can be treated successfully with ceftriaxone. (+info)
Imaging and laboratory investigation in herpes simplex encephalitis.
(24/1631)
A 14 day old baby presented with signs of an acute encephalitis. Clinically, herpes simplex encephalitis (HSE) was suspected. Early MRI and EEG were normal and there was rapid clinical improvement. A negative polymerase chain reaction (PCR) result on the initial CSF sample seemed to make HSE most unlikely. This diagnosis was subsequently proved after demonstration of specific antibody production using immunoelectrophoresis of the CSF. The child had extensive damage to brain tissue. The need for sequential analysis of CSF in making or refuting this diagnosis is illustrated. (+info)