Design and fabrication of label-free biochip using a guided mode resonance filter with nano grating structures by injection molding process.

This paper introduces technology to fabricate a guided mode resonance filter biochip using injection molding. Of the various nanofabrication processes that exist, injection molding is the most suitable for the mass production of polymer nanostructures. Fabrication of a nanograting pattern for guided mode resonance filters by injection molding requires a durable metal stamp, because of the high injection temperature and pressure. Careful consideration of the optimized process parameters is also required to achieve uniform sub-wavelength gratings with high fidelity. In this study, a metallic nanostructure pattern to be used as the stamp for the injection molding process was fabricated using electron beam lithography, a UV nanoimprinting process, and an electroforming process. A one-dimensional nanograting substrate was replicated by injection molding, during which the process parameters were controlled. To evaluate the geometric quality of the injection molded nanograting patterns, the surface profile of the fabricated nanograting for different processing conditions was analyzed using an atomic force microscope and a scanning electron microscope. Finally, to demonstrate the feasibility of the proposed process for fabricating guided mode resonance filter biochips, a high-refractive-index material was deposited on the polymer nanograting and its guided mode resonance characteristics were analyzed.

Outcomes of neurocritical care.

Outcomes research is a new and developing field that attempts to better measure the results of medical care. Neurocritical care is a relatively new field of medicine focusing on the care of critically ill patients with primary or secondary neurologic problems. Much needs to be done to examine the outcomes of neurocritical care, and the following is a review of the pertinent concepts of both outcomes and neurocritical care research.

Early identification of patients at risk for symptomatic vasospasm after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: To develop a scheme for early identification of individuals at risk for symptomatic vasospasm after subarachnoid hemorrhage (SAH). DESIGN: Analysis of prospectively collected data from the placebo-treated group in a multicenter clinical trial. SETTINGS: Fifty-four neurosurgical centers in North America. MEASUREMENTS AND MAIN RESULTS: We identified independent predictors of symptomatic vasospasm using stepwise logistic regression analysis from demographic, clinical, laboratory, and neuroimaging characteristics of the participants. We developed a scoring system (symptomatic vasospasm risk index) based on a combination of these predictors. Out of 283 patients in the analysis (all treated with oral nimodipine), 93 (33%) developed symptomatic vasospasm within 14 days after SAH. There were four independent predictors of symptomatic vasospasm: thickness of subarachnoid clot on computed tomographic scan (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.8-10.0); early rise in middle cerebral artery mean flow velocity (MCA-MFV), defined as a value > or =110 cm/sec recorded on or before post-SAH day 5 (OR, 1.9; 95% CI, 1.1-3.3), Glasgow Coma Scale score <14 (OR, 1.8; 95% CI, 1.1-3.1); and rupture of anterior cerebral or internal carotid artery aneurysm (OR, 1.9; 95% CI, 1.0-3.4). The probability of identifying patients who would develop symptomatic vasospasm (percentage of area under receiver operating characteristics curve +/- SEM) was higher with symptomatic vasospasm risk index (68%+/-8%) compared with thickness of clot (62%+/-8%; p = .08) or MCA-MFV (45%+/-7%, p < .05) criteria alone. CONCLUSIONS: Patients at high risk for symptomatic vasospasm can be identified early in the course of SAH using a risk index. A risk index based on a combination of variables may represent a predictive paradigm superior to conventionally used criteria based on clot thickness or MCA-MFV criteria.

Factors associated with aneurysm size in patients with subarachnoid hemorrhage: effect of smoking and aneurysm location.

OBJECTIVE: Intracranial aneurysm size is an important determinant of risk of rupture and outcome after rupture. Risk factors influencing aneurysm formation and growth are not well defined. In this study, we examined the association between known risk factors for cerebrovascular disease and size of intracranial aneurysms in patients with aneurysmal subarachnoid hemorrhage. METHODS: We analyzed prospectively collected data from the placebo-treated group in a multicenter clinical trial conducted at 54 neurosurgical centers in North America. The presence, location, and size of intracranial aneurysms were determined by review of the admission angiograms. Pertinent information regarding the presence of various cerebrovascular risk factors was collected for each patient. Using logistic regression analysis, we identified independent determinants of aneurysm size from demographic, clinical, and angiographic characteristics of the participants. The impact of aneurysm size on 3-month mortality was analyzed after adjusting for potential confounding factors. RESULTS: For 298 patients admitted with subarachnoid hemorrhage, the ruptured aneurysms were graded as small (<13 mm) in 235 patients (79%) and large (> or =13 mm) in 63 patients (21%). In the logistic regression model, both smoking at any time (odds ratio, 2.2; 95% confidence interval, 1.1-4.5) and middle cerebral artery origin (odds ratio, 2.5; 95% confidence interval, 1.3-4.9) were independently associated with large aneurysms. Neither hypertension, diabetes mellitus, nor alcohol and illicit drug use were associated with large-sized aneurysms. After adjusting for initial Glasgow Coma Scale score and age in the logistic regression model, the presence of large-sized aneurysms was independently associated with 3-month mortality (odds ratio, 2.3; 95% confidence interval, 1.1-4.8). CONCLUSION: Cigarette smoking and middle cerebral artery origin seem to increase the risk for developing large aneurysms in patients predisposed to intracranial aneurysm formation. Further studies are required to investigate the mechanism underlying the association between cigarette smoking and intracranial aneurysm formation.

Vertebrobasilar dolichoectasia associated with Marfan syndrome.

We report a 37-year-old woman with Marfan syndrome (MFS) who presented with acute myelopathy secondary to a subdural spinal hematoma. The patient died of a subarachnoid hemorrhage 4 days later. Autopsy showed a markedly ectatic vertebrobasilar system with fragmentation of the internal elastic lamina. Microscopic examination of the aorta similarly showed a fragmented internal elastic lamina. We discuss the implications of our patient's early onset vertebrobasilar dolichoectasia; this intracranial disease represents a rare cause of subarachnoid hemorrhage in MFS.

Prognostic value and determinants of ultraearly angiographic vasospasm after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: A small number of patients with aneurysmal subarachnoid hemorrhage have angiographic evidence of cerebral vasospasm within 48 hours of the onset of hemorrhage. The present study analyzes the prognostic value and determinants of this ultraearly angiographic finding. METHODS: We analyzed prospectively collected data from the placebo-treated group in a multicenter clinical trial conducted at 54 neurosurgical centers in North America. The presence and severity of ultraearly angiographic vasospasm (UEAV) was determined by a blinded review of the admission angiograms. Using logistic regression analysis, we identified independent determinants of UEAV from demographic, clinical, laboratory, and neuroimaging characteristics of the patients. The impact of UEAV on the risk of symptomatic vasospasm and 3-month outcome was analyzed after adjusting for potential confounding factors. RESULTS: Of 296 patients in the analysis, 37 (13%) had angiographic evidence of vasospasm at admission. An initial Glasgow Coma Scale score of less than 14 (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-6.0), and serum sodium greater than 138 mmol/L (OR, 3.4; 95% CI, 1.5-8.3) were associated with UEAV. UEAV was associated with increased risk of symptomatic vasospasm (OR, 2.5; 95% CI, 1.2-5.4) and poor outcome at 3 months (OR, 2.8; 95% CI, 1.2-6.3), after adjusting for other variables. This risk of symptomatic vasospasm was not influenced by early surgery (within 48 h of hemorrhage onset). Poor outcome was more likely to occur in patients with UEAV who did not undergo early surgery (P = 0.03). CONCLUSION: Our analysis suggests that patients with angiographic evidence of vasospasm at admission are at high risk for both symptomatic vasospasm and poor outcome. We also found that early surgery did not aggravate this risk.

Complex partial status epilepticus accompanied by serious morbidity and mortality.

Nonconvulsive status epilepticus (NCSE) accounts for approximately 20% of all status epilepticus (SE). Although convulsive SE is recognized as a medical emergency, prompt diagnosis and treatment of patients with NCSE is often not emphasized because its consequences are thought to be benign. We report 10 patients with persistent neurologic deficits or death after well-documented NCSE in the form of complex partial status epilepticus (CPSE). All patients had prolonged CPSE lasting 36 hours or longer, as documented by clinical and EEG findings. Causes for CPSE were preexisting epilepsy with partial and secondarily generalized seizures (3 patients), vascular disease (2 patients), encephalitis (2 patients), and metabolic disease (1 patient); causes were unknown for two patients. Poor outcomes identified included persistent (lasting at least 3 months) or permanent cognitive or memory loss (5 patients), cognitive or memory loss plus motor and sensory dysfunction (3 patients), and death (3 patients). NCSE in the form of CPSE is not a benign entity. Serious morbidity and mortality may occur due to the adverse effects of prolonged seizures and as a result of acute brain disorders that precipitate the seizures.