Intraventricular cryptococcal cysts.

The case of a 55-year-old immunocompetent woman with central nervous system cryptococcosis and multiple intraventricular cysts is presented. The cysts did not enhance on MR and had signal characteristics similar to cerebrospinal fluid on T1- and T2-weighted images; their intensity was lower than cerebrospinal fluid on proton density-weighted images.

NMDA- and endothelin-1-induced increases in blood-brain barrier permeability quantitated with Lucifer yellow.

At 48 h following intrastriatal injection of N-methyl-D-aspartate (NMDA; 100 nmol/microliter) or endothelin-1 (ET-1; 143 pmol/microliter), significant increases in brain penetration of the highly polar, fluorescent tracer Lucifer yellow were observed. The competitive NMDA receptor antagonist selfotel (CGS-19755; 30 nmol/microliter, i.c.) significantly reduced the NMDA-induced increases in blood-brain barrier permeability, but not those induced by ET-1. These results suggest that NMDA receptors can mediate increases in blood-brain barrier permeability but do not primarily mediate increases in blood-brain barrier permeability caused by ET-1. This is the first study to our knowledge investigating the relationship between excitotoxicity and disruption of the blood-brain barrier, a major pathophysiological event in stroke and traumatic brain injury.

Pump-regulated lumbar subarachnoid drainage.

OBJECTIVE: The diversion of cerebrospinal fluid (CSF) has been widely used in the prevention and treatment of CSF fistulae. A common method is the use of a lumbar drainage system. Although it is effective, several serious complications can develop, which can be avoided by regulating the flow of CSF with a standard intravenous infusion pump. TECHNIQUE: We present a simple, inexpensive, and accurate method of flow-controlled lumbar subarachnoid drainage that minimizes patient discomfort and the unpredictability of a gravity-dependent system. This system uses a standard lumbar drain connected to an intravenous infusion pump to provide drainage of CSF in a constant and predictable manner. RESULTS: A total of 42 patients from two institutions were treated with this method. CSF fistulae occurred secondary to trauma in 9 patients, after spinal surgery in 11 patients, after transsphenoidal surgery in 10 patients, and after cranial base surgery in 12 patients. Resolution of the fistula was attained in 36 of 42 patients. There were no deaths, no cases of deep venous thrombosis, and no incidence of meningitis. One patient developed tension pneumocephalus, and two patients developed headache with nausea and vomiting. All patients were ambulatory, and only three patients required narcotic analgesia for headaches. CONCLUSION: Pump-regulated lumbar subarachnoid drainage is safe and effective in the treatment of CSF fistulae, as reported elsewhere in the literature. The advantage of this method is that the drainage of CSF can be carefully controlled and titrated in a predictable fashion. Because the system is independent of gravity to produce drainage of CSF, patients are not confined to bed and serious complications of overdrainage can be avoided.

Fusion and instrumentation at C1-3 via the high anterior cervical approach.

OBJECT: The high anterior cervical, retropharyngeal approach to the anterior foramen magnum and upper cervical spine is a favorable alternative to the transoral and posterolateral approaches, which both cause instability of the craniovertebral junction. Previously, such instability was corrected via an occipitocervical fusion during a separate surgical procedure. METHODS: Seven patients requiring C-2 corpectomy (foramen magnum meningioma [two patients], critical stenosis secondary to rheumatoid arthritis [two patients], C-2 fracture [two patients], and stenosis secondary to Rickets [one patient]) are presented. All patients underwent C1-3 fusion followed by instrumentation with a Caspar plate. A solid fusion was achieved in six patients. One patient experienced erosion of the anterior arch of C-1 requiring posterior stabilization. CONCLUSIONS: Fusion and instrumentation at C1-3 can be performed safely and with minimal increase in surgical time. In selected patients, this may eliminate the need for an additional posterior procedure and maintain occipital-C1 mobility.

Delayed appearance of a traumatic intracranial aneurysm. Case report and review of the literature.

Giant traumatic intracranial aneurysms are rare, and thus their incidence and clinical behavior are poorly understood. In most cases, traumatic aneurysms develop and become symptomatic within months following injury. The authors present the case of a 46-year-old war veteran, in whom a giant internal carotid artery aneurysm developed as a result of a penetrating cranial shrapnel injury sustained 25 years earlier during the Vietnam war. The aneurysm had not been evident on previous imaging studies. At surgery, a piece of shrapnel was found embedded in the dome of the aneurysm. The presentation, diagnosis, management, and treatment options related to this lesion are discussed.

Extensive subdural mass.

An unusual case of a 62-year-old man with focal seizures, tinnitus, and progressive left hemiparesis due to an extensive subdural plasma cell granuloma is presented. Five-year clinical and radiologic follow-up demonstrating the chronic yet progressive nature of this granuloma is presented. This is the first report of focal calcification seen in an intracranial plasma cell granuloma. The imaging, neuropathologic, and clinical characteristics of this rare lesion are reviewed.

Calbindin-D28k in subsets of medulloblastomas and in the human medulloblastoma cell line D283 Med.

OBJECTIVE: To evaluate the antigenic expression of calbindin-D28k in surgically resected cerebellar medulloblastomas and the human medulloblastoma cell line D283 Med in relation to glial neoplasms, the human glioblastoma (U-251 MG) and rat glioma (C-6) cell lines, and other primary and metastatic brain tumors. DESIGN: Immunohistochemical staining was performed using an antiserum and a monoclonal antibody against calbindin-D28k on (1) formalin-fixed, paraffin-embedded human, predominantly posterior fossa, brain tumor specimens (49 medulloblastomas, 59 glial and mesenchymal primary central nervous system tumors, 1 posterior fossa rhabdoid tumor, and 34 metastatic tumors); (2) formalin-70% alcohol-, or Bouin's-fixed tumor cell lines (D283 Med, U-251 MG, and C-6) maintained in a three-dimensional gelatin foam (Gelfoam matrix) system, with or without treatment with dibutyryl cyclic adenosine monophosphate; and (3) formalin-fixed, paraffin-embedded C-6 glioma cells transplanted intracerebrally to rats. RESULTS: Calbindin-D28k immunohistochemical staining was detected in 20 of 49 cerebellar medulloblastomas and in cells of the human medulloblastoma cell line D283 Med grown in gelatin Gelfoam matrices, with or without treatment with dibutyryl cyclic adenosine monophosphate. In surgical resection specimens, calbindin-D28k reactivity was evident in populations of poorly differentiated cells of classic (non-nodular) medulloblastomas (16/20) and in mature Purkinje neuronlike phenotypes in medulloblastomas with ganglion cells (4/6) but was absent in desmoplastic medulloblastomas, including in areas of neoplastic neuritogenesis ("pale islands") (0/23). Calbindin-D28k staining was also present in D283 Med explants for up to 29 days in vitro. Reactivity was more widespread in dibutyryl cyclic adenosine monophosphate-treated cultures, coinciding with neuronal morphologic alterations of cultured cells. Focal calbindin-D28k stainig was present in neural-like cells of an embryonal cerebellar tumor with divergent mesenchymal, epithelial, and neuroectodermal/neuroendocrine differentiation suggestive of a malignant rhabdoid tumor. No calbindin-D28k staining was obtained in primary glial and mesenchymal (intra- and extra-axial) brain tumors (0/59), in explants of human glioblastoma cell line U-251 MG, or in the rat glioma line C-6 maintained in Gelfoam matrices or transplanted intracerebrally. Among 34 epithelial and mesenchymal tumors metastatic to the posterior fossa, only subpopulations of cells in two small-cell (neuroendocrine) carcinomas originating in the lung were calbindin positive. CONCLUSION: Calbindin-D28k expression in classic medulloblastomas, medulloblastomas with ganglion cells, and in the human medulloblastoma cell line D283 Med (which was derived from a metastatic classic medulloblastoma) suggests a phenotypic kinship between subsets of this tumor and neuronal progeny of the ventricular neuroepithelium, thus conferring additional support for its neuroblastic nature.

Post-anesthesia uncal herniation secondary to a previously unsuspected temporal glioma.

We report the case of a 21-year-old male who sustained an uncal herniation and subsequent brain death following general anesthesia, for a minor orthopedic procedure, owing to the presence of a large, unsuspected temporal glioma. The possible factors responsible for the precipitation of this event are appraised.

Chemotherapy in experimental brain tumor, part 1: in vitro colorimetric MTT assay.

This study concerns the use of the MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide] colorimetric assay to evaluate the chemosensitivity of the C6 rat glioma cell line to a panel of twelve chemotherapeutic agents. In a previous study of in vitro chemosensitivity of human glioma cell lines, the present authors found a range of sensitivities of the respective cell lines to a panel of chemotherapeutic agents [1]. We then devised an experimental strategy to begin an in vivo evaluation of the correlation between in vitro chemosensitivity and clinical response in an in vivo animal model, such as the model employing the C6 rat glioma cell line. As a step towards utilizing the C6 rat glioma in vivo model, we carried out the present study (Part 1) to determine the correspondence between chemosensitivity to human glioma cell lines and the rat C6 glioma cell line. If a correspondence were to be found, this would enable experimental use of the C6 tumor model for in vivo testing of chemotherapeutic agents. As reported in this paper (Part 1), a correspondence was found, suggesting that the C6 rat glioma represents a suitable model of human glioma for chemotherapeutic studies. This finding served as a basis for proceeding with an in vivo study of chemotherapeutic efficacy which is the subject of a companion report [2].

Pump-regulated cerebrospinal fluid drainage.

The drainage of cerebrospinal fluid (CSF) from the lumbar subarachnoid space is an effective technique for the treatment of CSF fistula and control of intracranial pressure in children and adults. The use of the lumbar drain poses unique challenges, however, in the pediatric population. We present a safe and effective method of pump-controlled lumbar subarachnoid drainage. This technique allows accurate titration of CSF removal while providing a closed system which is not sensitive to position changes or patient activity. Four case histories are reviewed.

Oxygen saturation monitoring in experimental surgery: a comparison of pulse oximetry and arterial blood gas measurement.

Experimental surgery in animal models often requires prolonged periods of general anesthesia. Animals undergoing these procedures may have difficulty maintaining normal ventilation and oxygenation and therefore may require physiologic monitoring and endotracheal intubation to avoid hypoxia that could adversely affect the results of the investigation. Monitoring has traditionally included measurements of PaO2, PCO2, pH, and oxygen saturation calculated from arterial blood. Endotracheal intubation and placement of arterial catheters necessary for the intraoperative collection of specimens for blood gas analysis are labor-intensive and time-consuming. In this study, rats undergoing thoracic laminectomy as part of a study on spinal cord injury were monitored by noninvasive pulse oximetry, with a reflectance transducer placed on the skin/fur of the neck overlying the cervical carotid artery. Comparison of these data with intermittent arterial blood gas measurements in the same animals indicated > 90% concordance with the pulse oximetry values. We also determined the fraction of inspired oxygen (FiO2) that, delivered via facemask, can achieve at least the minimal normal oxygen saturation (SaO2) of 90%. These findings suggest that physiologic monitoring during experimental rodent surgery can be substantially simplified by pulse oximetry and by delivery of oxygen via facemask, eliminating the need for arterial blood gas determinations or endotracheal intubation.

Chemotherapy in experimental brain tumor, part 2: pretreatment with leukotriene C4 prolongs survival.

Previous work in our laboratory has shown a correspondence between the chemosensitivity of C6 rat glioma and that of human glioblastoma (GBM) to a panel of chemotherapeutic agents in vitro, as determined by the MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide] colorimetric assay. In the present study, an in vivo model of intracerebral C6 glioma in Sprague-Dawley rats was used to determine if a correlation exists between in vitro chemosensitivity and in vivo survival of the animals, and post-mortem histopathological changes in the tumor. Cisplatin (CDDP) and methotrexate (MTX), agents previously shown to demonstrate high and low in vitro cytotoxicity, respectively, against C6, were administered by intra-carotid infusion over the course of two days. In a separate series of animals, LTC4 was administered prior to infusion of CDDP or MTX; LTC4 was used in view of its known, selective, vasogenic effect on the permeability of brain tumor capillaries. It was found that survival of animals treated with CDDP alone was increased, although this did not reach statistical significance; histopathologically, CDDP-treated animals showed significant tumor necrosis. However, in CDDP-treated animals, pre-treatment with LTC4 increased survival to a statistically significant degree. When administered alone, LTC4 (not followed by CDDP) had no effect on either survival or histology. The survival-enhancing effect of CDDP, when combined with LTC4, was probably not due to any cytotoxic effect of LTC4; this is based on our finding that, on the in vitro MTT colorimetric assay, LTC4 showed low cytotoxicity for C6 glioma cells. By contrast with CDDP, MTX -- with or without pretreatment with LTC4 -- affected neither survival nor tumor histology. With respect to the question of correspondence between the MTT colorimetric in vitro assay and in vivo effect, MTX showed a clear correlation: low cytotoxicity in vitro and poor in vivo response. In the case of CDDP, the correspondence was not clear-cut: there was a high level of in vitro chemosensitivity of the C6 cell line to CDDP as well as post-mortem tumor necrosis, but in vivo testing showed no significant prolongation of survival. However, pre-treatment with LTC4 did significantly extend survival in animals treated with CDDP.