Multivariate analysis of 3D ToF-SIMS images: method validation and application to cultured neuronal networks.

Advanced data analysis tools are crucial for the application of ToF-SIMS analysis to biological samples. Here, we demonstrate that by using a training set approach principal components analysis (PCA) can be performed on large 3D ToF-SIMS images of neuronal cell cultures. The method readily provides access to sample component information and significantly improves the images' signal-to-noise ratio (SNR).

Implementing conventional logic unconventionally: photochromic molecular populations as registers and logic gates.

In this paper we detail experimental methods to implement registers, logic gates and logic circuits using populations of photochromic molecules exposed to sequences of light pulses. Photochromic molecules are molecules with two or more stable states that can be switched reversibly between states by illuminating with appropriate wavelengths of radiation. Registers are implemented by using the concentration of molecules in each state in a given sample to represent an integer value. The register's value can then be read using the intensity of a fluorescence signal from the sample. Logic gates have been implemented using a register with inputs in the form of light pulses to implement 1-input/1-output and 2-input/1-output logic gates. A proof of concept logic circuit is also demonstrated; coupled with the software workflow describe the transition from a circuit design to the corresponding sequence of light pulses.

Relationship between intracranial pressure monitoring and outcomes in severe traumatic brain injury patients.

Intracranial pressure (ICP) monitoring is recommended in patients with a severe traumatic brain injury (TBI) and an abnormal computed tomography (CT) scan. However, there is contradicting evidence about whether ICP monitoring improves outcome. The purpose of this study was to examine the relationship between ICP monitoring and outcomes in patients with severe TBI. From February 2001 to December 2008, a total of 477 consecutive adult (> or =18 years) patients with severe TBI were included retrospectively in the study. Patients who underwent ICP monitoring (n=52) were compared with those who did not (n=425). The primary outcome was hospital mortality. Secondary outcomes were ICU mortality, mechanical ventilation duration, the need for tracheostomy, and ICU and hospital length of stay (LOS). After adjustment for multiple potential confounding factors, ICP monitoring was not associated with significant difference in hospital or ICU mortality (odds ratio [OR] = 1.71, 95% confidence interval [CI] = 0.79 to 3.70, P = 0.17; OR = 1.01, 95% CI = 0.41 to 2.45, P = 0.99, respectively). ICP monitoring was associated with a significant increase in mechanical ventilation duration (coefficient = 5.66, 95% CI = 3.45 to 7.88, P < 0.0001), need for tracheostomy (OR = 2.02, 95% CI = 1.02 to 4.03, P = 0.04), and ICU LOS (coefficient = 5.62, 95% CI = 3.27 to 7.98, P < 0.0001), with no significant difference in hospital LOS (coefficient = 8.32, 95% CI = -82.6 to 99.25, P = 0.86). Stratified by the Glasgow Coma Scale score, ICP monitoring was associated with a significant increase in hospital mortality in the group of patients with Glasgow Coma Scale 7 to 8 (adjusted OR = 12.89, 95% CI = 3.14 to 52.95, P = 0.0004). In patients with severe TBI, ICP monitoring was not associated with reduced hospital mortality, however with a significant increase in mechanical ventilation duration, need for tracheostomy, and ICU LOS.

Cerebrospinal fluid lavage in the treatment of inadvertent intrathecal vincristine injection.

Vincristine, a widely used antineoplastic agent, is extremely toxic to the central nervous system. If given intrathecally, it produces a rapidly ascending, usually fatal, neuromyeloencephalopathy. We report a case of this complication in a 7-year-old girl with acute lymphoblastic leukemia who was receiving maintenance chemotherapy. During one treatment 0.5 mg of vincristine was erroneously injected into the lumbar subarachnoid space. Cerebrospinal fluid lavage was established within 2 h and continued for 24 h. After 7 days she developed a progressive sensorimotor paraplegia, which eventually stabilized as a paraparesis. Neurophysiological studies were consistent with an axonal type sensorimotor neuropathy. Magnetic resonance imaging of the spine was normal. Vincristine binds to cells, blocking mitosis, thus causing cell death. The associated central nervous system lesions are those of an ascending chemical leptomeningitis and ventriculitis. Cerebrospinal fluid lavage dilutes and removes the drug, thus limiting neural damage. At present this is the only treatment for intrathecal vincristine injection, and its early use in such an event is considered mandatory.

Efficient, low-threshold collinear and noncollinear beta-barium borate optical parametric oscillators.

The performance of collinear and noncollinear pulsed barium borate optical parametric oscillators with third-harmonic Nd:YAG pumping is analyzed. The effects of tangential phase matching and pump Poynting vector walk-off compensation are shown to enhance noncollinear operation. However, we show that these effects are mutually exclusive for a typeI beta-barium borate optical parametric oscillator and furthermore that tangential phase matching is dominant. The selection of a collinear or a noncollinear configuration is determined by pump divergence and spot size as well as by crystal aperture. With a pump divergence of 4mrad, noncollinear operation is optimal. The highest slope efficiency, 37%, and the lowest threshold, 5mJ, are obtained with nearly perfect tangential phase matching. For a pump divergence of less than 2mrad and a similar spot size, collinear operation gives the lowest threshold, 3.2mJ, and the highest slope efficiency, 33%.

Adult diastematomyelia.

With modern imaging techniques, various types of spinal dysraphism are being diagnosed in adults with increasing frequency. We report a 42-year-old woman with diastematomyelia whose symptoms characteristically were precipitated by trauma. She exhibited other typical features such as a posterior midline hair patch and vertebral malformations. Metrizamide myelography with computerized tomography showed a bony septum at T11 with a cleft at T9-T11 separating two dural tubes each of which contained a single spinal hemicord. The septum was excised with complete relief of symptoms.

Diastematomyelia in adults. A review.

A consecutive series of 45 cases of diastematomyelia in adults is analyzed. The majority of patients were females with a 3.4:1 female to male ratio. The ages ranged from 19 to 76 with a mean of 37.8 years. The lesion was usually located in the lumbar region. In 17 patients the development of symptoms was associated with specific incidents or events, usually trauma. Twelve patients had pre-existing static musculoskeletal or neurologic abnormalities and 20 had cutaneous spinal lesions suggesting dysphraphism. The symptoms and signs included pain and a variety of sensorimotor and/or sphincteric abnormalities. Metrizamide CT scanning proved to be the most useful diagnostic procedure. Only 4 patients were investigated by MRI and from the information available its role in the diagnosis of adult diastematomyelia is not established. Twenty-three of 24 patients treated by surgery showed marked improvement.

Multiple noncontiguous fractures of the cervical spine.

Multiple noncontiguous fracture-subluxations of the cervical spine are fractures and subluxations separated by at least one normal intervening cervical vertebra. A review of all 66 consecutive cervical spine fractures treated by the Division of Neurosurgery at the University of Ottawa during 26 consecutive months revealed six such cases (9%). These injuries are more common than previously recognized. Special consideration is required in their treatment because of the presence of a mobile intermediate segment in some of these patients.

Intraarterial mitomycin-C for recurrent brain metastases.

Fifteen consenting patients with brain metastases recurrent after cranial irradiation were treated with intraarterial mitomycin-C, 15 mg/m2, administered in a total final volume of 100 ml 0.45% saline over 20 min through a transfemoral catheter with a 0.2-mu in-line filter. There were 2 early deaths (one probably drug-related). Of the 13 evaluable patients, 6 (46%) responded, with both computed tomography (CT) scan and neurological improvement. Median response duration was 25 weeks, and median survival of all 15 patients was 17 weeks. Neurological, ocular, and local skin toxicity were dose-limiting. The degree of toxicity was comparable to that we have noted with other intracarotid regimens, and it appears to be less toxic when infused into the vertebral artery than are most other drugs (although experience is still limited and caution still needs to be exercised). We do not recommend that this replace or be added to cranial irradiation as front-line treatment of brain metastases, but we feel that it is an effective and reasonably well-tolerated regimen for treatment of brain metastases that have recurred after cranial irradiation. We are currently initiating studies of intraarterial mitomycin-C combined with intraarterial cisplatin and teniposide (VM-26) as treatment for recurrent brain metastases.

Metrizamide CT scanning in spinal nerve root cysts.

Two cases of lumbosacral root cysts of different etiology are reported. Their specific radiographic features are described using the combined technique of metrizamide myelography followed by computerized tomography of the spine. The terminology of intraspinal cysts is reviewed and their distinguishing features discussed.

Interhemispheric subdural hematoma.

Although relatively uncommon, interhemispheric subdural hematoma (ISDH) occurs more frequently than was suspected before the advent of computerized tomographic (CT) scanning. When its mass is sufficiently large to compress the medial cerebral hemisphere, specific focal neurological abnormalities may occur. These include weakness of the contralateral leg, or contralateral hemiparesis with the leg being weaker than the arm. On the unenhanced CT scan ISDH is seen as a crescent shaped, midline hyperdensity. Treatment is dictated by the clinical course. Evacuation of the hematoma by parasagittal craniotomy is recommended if the symptoms are pronounced.

Intraspinal cysts: a classification and literature review.

Advances in radiologic technology have allowed the identification of a variety of cystic lesions of spinal nerve roots. Failure to appreciate the different characteristics of these cysts has led to a confusion in terminology, with different terms often being used to describe the same lesion. In an attempt at clarification, the literature is reviewed and a simplified classification of spinal cysts presented. The distinguishing features of each type of cyst, its investigation, and appropriate treatment are discussed.

Spontaneous carotid-cavernous fistula and multiple arterial dissections in type IV Ehlers-Danlos syndrome. Case report.

A 43-year-old woman without phenotypic expression of Ehlers-Danlos syndrome developed a spontaneous unilateral carotid-cavernous fistula (CCF). Attempts at balloon occlusion of the CCF were unsuccessful, and caused multiple arterial dissections and lacerations eventually leading to massive retroperitoneal hemorrhage and death. The CCF was demonstrated during postmortem studies. In addition, the patient had independent dissections of the internal carotid artery at the site of the fistula and an intracavernous aneurysm of the contralateral internal carotid artery. Despite widespread dissections, the major arteries showed only mild histological abnormalities. Morphometric analysis of collagen from the aorta revealed an increase in large-sized fibers, consistent with deficiency of Type III collagen.