Histologic characteristics of normal perivascular spaces along the optic tract: new pathogenetic mechanism for edema in tumors in the pituitary region.
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BACKGROUND AND PURPOSE: Perivascular (PV) spaces are known to distend and cause edema along the optic tract (OT) in pituitary-region tumors. Interstitial fluid may be retained in PV spaces when tumors block their drainage outlets to subarachnoid spaces. However, these spaces and their outlets have not been anatomically elucidated. Our purpose was to evaluate how often large PV spaces are present along the OT and demonstrate their superficial communication points to adjacent subarachnoid spaces. METHODS: We examined serial histologic sections of 10 hemispheric blocks obtained from cadavers without cerebral abnormality. RESULTS: Large PV spaces, 0.5-1.5 mm in maximum height, were always present along the middle portion of the OT. Perforation points of the largest spaces were noted at the medial sulcus of the OT in seven hemispheres and through the OT in three. CONCLUSION: Large PV spaces are present along the middle portion of the OT. Their communication point to adjacent subarachnoid spaces was histologically demonstrated. The locations and variations of the outlet of large PV spaces explain the clinical features of edemas; these findings anatomically support the hypothesis that blockage of the outlets to subarachnoid spaces may play a role in distending the PV spaces and in causing edema in pituitary-region tumors. Only MR imaging has revealed this change; further pathologic investigations are awaited. (+info)
Method for inducing experimental pneumococcal meningitis in outbred mice.
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BACKGROUND: Streptococcus pneumoniae is the leading cause of bacterial meningitis. Pneumococcal meningitis is associated with the highest mortality among bacterial meningitis and it may also lead to neurological sequelae despite the use of antibiotic therapy. Experimental animal models of pneumococcal meningitis are important to study the pathogenesis of meningitis, the host immune response induced after infection, and the efficacy of novel drugs and vaccines. RESULTS: In the present work, we describe in detail a simple, reproducible and efficient method to induce pneumococcal meningitis in outbred mice by using the intracranial subarachnoidal route of infection. Bacteria were injected into the subarachnoid space through a soft point located 3.5 mm rostral from the bregma. The model was tested with several doses of pneumococci of three capsular serotypes (2, 3 and 4), and mice survival was recorded. Lethal doses killing 50 % of animals infected with type 2, 3 and 4 S. pneumoniae were 3.2 x 10, 2.9 x 10 and 1.9 x 10(2) colony forming units, respectively. Characterisation of the disease caused by the type 4 strain showed that in moribund mice systemic dissemination of pneumococci to blood and spleen occurred. Histological analysis of the brain of animals infected with type 4 S. pneumoniae proved the induction of meningitis closely resembling the disease in humans. CONCLUSIONS: The proposed method for inducing pneumococcal meningitis in outbred mice is easy-to-perform, fast, cost-effective, and reproducible, irrespective of the serotype of pneumococci used. (+info)
Enlarged perivascular spaces are associated with cognitive function in healthy elderly men.
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OBJECTIVES: Increased white matter (WM) lesions on magnetic resonance imaging (MRI) are associated with worse cognitive function in older people. Enlarged perivascular spaces (EPVS) commonly coexist with and share some risk factors for WM lesions but are not quantified in published scales. It is not known whether the extent of EPVS is also associated with cognitive function. We tested the hypothesis that more EPVS would be associated with worse cognitive function. METHODS: Ninety seven healthy men (65-70 years), not on medications, underwent MRI scanning and comprehensive cognitive testing. EPVS were quantified in both the basal ganglia/centrum semiovale and the hippocampus, and WM lesions were measured. RESULTS: Scores on published WM lesion rating scales intercorrelated highly significantly and positively (rho = 0.61 to 0.91, p<0.0001). A summary (WML) factor derived from principal components analysis of the WM scales correlated with EPVS in the basal ganglia/centrum semiovale (rho = 0.48, p<0.0001) but not in the hippocampus. EPVS scores in the basal ganglia/centrum semiovale correlated significantly and negatively with non-verbal reasoning (rho = -0.21, p = 0.038) and general visuospatial ability (rho = -0.22, p = 0.032), adjusted for prior intelligence. The WML factor correlated significantly and negatively with visuospatial ability, as previously reported, and showed an unexpected positive correlation with one test of verbal memory (list-learning). CONCLUSIONS: These findings suggest that increased EPVS are correlated with worse cognitive function. Future studies examining changes in WM with ageing should consider incorporating measures of EPVS and examine the sequence of EPVS and WM lesion development over time. More work is needed to develop valid and reliable measures of EPVS. (+info)
Intramedullary spinal cord abscess.
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We report a patient with a chronic intramedullary spinal cord abscess who suffered an episode of acute meningitis due to rupture of the abscess into the subarachnoid space. (+info)
evaluation of communication between intracranial arachnoid cysts and cisterns with phase-contrast cine MR imaging.
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BACKGROUND AND PURPOSE: The demonstration of communication between arachnoid cysts (ACs) and the adjacent subarachnoid space is a prerequisite for their proper management. CT cisternography (CTC) is the conventional method for functional evaluation of ACs. The sensitivity of MR imaging to CSF flow has been demonstrated, but reports of the clinical usefulness of MR CSF flow techniques in this application are limited. The purpose of our study was to prospectively evaluate the accuracy of MR CSF flow study as an alternative to CTC in this setting. METHODS: MR CSF flow study with retrospective ECG-gated 2D, fast low-angle shot, phase-contrast (PC), cine gradient-echo sequence was performed in 39 patients with an intracranial AC. Results were compared with intraoperative and CTC findings. RESULTS: PC cine MR imaging results were compatible with operative or CTC findings in 36 (92.3%) of 39 patients. Twenty-four cysts were noncommunicating, and 15 were communicating. Three cysts were evaluated as being noncommunicating on PC cine MR imaging (false-negative) but demonstrated contrast enhancement on CTC. No false-positive diagnoses occurred. All cysts regarded as being communicating on PC cine MR imaging were also found to be communicating on both confirmation methods. CONCLUSION: MR CSF flow imaging with a PC cine sequence can be incorporated in the imaging work-up of ACs. This is a reliable alternative to invasive CTC for the functional evaluation of ACs. (+info)
High volume of subarachnoid levobupivacaine decreases drug requirement in first stage labor analgesia.
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AIM: Using the statistic method of sequential allocation, we realized a prospective double-blind study in order to establish the minimum local anesthetic concentration (MLAC) of large intrathecal volume of levobupivacaine, during the first stage labour analgesia in spontaneous and induced laboring women. METHODS: Seventy-five nulliparous, at term, with cervical dilatation <5 cm parturients requesting combined spinal/epidural analgesia, were enrolled. The starting concentration was chosen according to recent literature. Total volume of study solution was 10 ml and efficacy was assessed with a visual analogue pain scale at the height of the uterine contraction. RESULTS: We established that MLAC of levobupivacaine, in 10 ml intrathecal volume, during the first stage of spontaneous and induced labour was 0.0134% and 0.0195%, respectively. No complications occurred during the study and the only side effect was shivering, which is common even in other anesthetic techniques. We produced a very selective sensitive block. Neither sympathetic nor motor block occurred. CONCLUSIONS: Low intrathecally concentration of local anesthetic allows the anesthetist to reduce the total amount of drug and improves not only the differential blockade between motor and sensitive but also between sympathetic and sensitive fibers. (+info)
Haemodynamic modifications after unilateral subarachnoid anaesthesia evaluated with transthoracic echocardiography.
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AIM: The aim of the study is the evaluation through transthoracic echocardiography of the haemodynamic modifications due to unilateral subarachnoid anaesthesia with bupivacaine 0.5% given for orthopaedic surgery. METHODS: In this prospective study, at the University Hospital Orthopedics surgical theater, 20 patients underwent orthopaedic surgery on the lower limbs. Unilateral spinal block was performed with hyperbaric bupivacaine 0.5%, 8 mg after a fluid challenge with saline solution 0.9%. Transthoracic echocardiography was performed and cardiac output was calculated from the left ventricular outflow tract (LVOT) with a recently validated technique. Cardiac output, stroke volume, ejection fraction, heart rate, mean arterial pressure were evaluated. These parameters were obtained before anaesthesia (t1), 5 minutes after anaesthesia (t2) and 16 minutes after anaesthesia (t3). RESULTS: Systolic, mean and diastolic arterial pressures after 5 min and 16 min from anaesthesia significantly decreased if compared to basal time (p<0.05 and p<0.001 respectively) while cardiac index (p<0.001) and ejection fraction (p<0.05) decreased only after 16 min from subarachnoid anaesthesia. CONCLUSION: Despite the fluid challenge we can not prevent a significant fall in the blood pressure and a decrease of the left ventricular function calculated with the decrease of cardiac output and of the left ventricular ejection fraction. (+info)
Subarachnoid sufentanil as sole agent vs standard spinal bupivacaine in transurethral resection of the bladder.
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AIM: The aim of the study was to determine whether intrathecal sufentanil alone provides an adequate analgesia for patients undergoing transurethral resection of the bladder (TURB) and to compare it to standard spinal bupivacaine anesthesia in terms of motor and sensory blockade, discharge time and side effects. METHODS: Sixty-two patients were blindly and randomly assigned to receive either intrathecal bupivacaine (10 mg of 0.5% hyperbaric bupivacaine) or intrathecal sufentanil (15 microg). Motor and sensory blockade was evaluated using a modified Bromage scale as well as cold and pinprick tests. Severity of pain was assessed by means of a 10-point verbal analog scale. RESULTS: We found that the mean duration of sensory blockade was similar for both sufentanil and bupivacaine patients but the quality of analgesia induced by sufentanil alone was poor as compared with spinal bupivacaine anesthesia. CONCLUSION: The subarachnoid administration of sufentanil 15 mg seems to be inadequate for TURB surgery. In addition, the advantage of a faster recovery we observed in sufentanil patients is minimized by the occurrence of a troublesome symptom such as pruritus. On the other hand, spinal bupivacaine produces an undesirable motor blockade exceeding, in our opinion, the requirement for TURB procedure. (+info)