In a discovery of the transfer of chloroplast biosynthesis activity to an inorganic material, ferredoxin-NADP
reductase (FNR), the pivotal redox flavoenzyme of photosynthetic CO
assimilation, binds ...tightly within the pores of indium tin oxide (ITO) to produce an electrode for direct studies of the redox chemistry of the FAD active site, and fast, reversible and diffusion-controlled interconversion of NADP
and NADPH in solution. The dynamic electrochemical properties of FNR and NADP(H) are thus revealed in a special way that enables facile coupling of selective, enzyme-catalysed organic synthesis to a controllable power source, as demonstrated by efficient synthesis of l-glutamate from 2-oxoglutarate and NH
.
Atherosclerosis of the major intracranial arteries is an important cause of ischemic stroke. We established measurement criteria to assess percent stenosis of a major intracranial artery (carotid, ...middle cerebral, vertebral, basilar) and determined the interobserver/intraobserver agreements and interclass/intraclass correlations of these measurements.
We defined percent stenosis of an intracranial artery as follows: percent stenosis = (1 - (D(stenosis)/D(normal))) x 100, where D(stenosis) = the diameter of the artery at the site of the most severe stenosis and D(normal) = the diameter of the proximal normal artery. If the proximal segment was diseased, contingency sites were chosen to measure D(normal): distal artery (second choice), feeding artery (third choice). Using a hand-held digital caliper, three neuroradiologists independently measured D(stenosis) and D(normal) of 24 stenotic intracranial arteries. Each observer repeated the readings 4 weeks later. We determined how frequently two observers' measurements of percent stenosis of each of the 24 diseased arteries differed by 10% or less.
Among the three pairs of observers, interobserver agreements were 88% (observer 1 versus observer 2), 79% (observer 1 versus observer 3), 75% (observer 2 versus observer 3) for the first reading and were 75% (observer 1 versus observer 2), 100% (observer 1 versus observer 3), and 71% (observer 2 versus observer 3) for the second reading. Intraobserver agreement for each of the observers was 88%, 83%, and 100%. Interclass correlation was 85% (first reading) and 87% (second reading). Intraclass correlation was 92% (first and second readings combined).
This method shows good interobserver and intraobserver agreements for the measurement of intracranial stenosis of a major artery. If validated in subsequent studies, this method may serve as a standard for the measurement of percent stenosis of an intracranial artery.
Background: Labial adhesion is one of the most common reasons for gynaecologic consultations in children. We sought to determine the prevalence of labial adhesions, mode of presentation and treatment ...in children at the Jos University Teaching Hospital. Materials and Methods: A retrospective study of labial adhesions in children from January 2004 to December 2013. Data on paediatric gynaecological consultations, and labial adhesions were retrieved from the gynaecological clinic and the theatre records. The case notes of those with labial adhesions were retrieved and the relevant data extracted. Results: The total number of paediatric patients seen at the gynaecology clinic over the study period was 379 and 25 had labial adhesion (6.6%). The majority (88%) presented in the first 2 years of life, all the patients were asymptomatic, and 2 (8%) had surgical separation of the adhesions while the rest were managed conservatively. A total of 5 (20%) came for follow-up. While 2 (8%) came a week later following surgical management, 3 (12%) came back more than 6 months later due to recurrence following conservative management. Conclusion: Labial adhesions account for significant proportion of paediatric gynaecologic consultations. They are usually asymptomatic, occur in the first 2 years of life and frequently managed conservatively.
Occlusion of an internal carotid artery stent was identified immediately post placement in a patient who had restenosis after prior angioplasty. An IV dose of abciximab was administered, and serial ...angiograms were performed. This resulted in partial resolution of the thrombus at 10 minutes and complete resolution at 20 minutes.
IntroductionOne common complication of subarachnoid hemorrhage (SAH) is cerebral vasospasm, a maladaptive response that can lead to a secondary stroke. Intrathecal (IT) administration of nicardipine ...holds promise as a safe treatment for cerebral vasospasm, when given every 6-8 hours for ~2 weeks upon confirmed diagnosis of cerebral vasospasm. Preliminary data suggest that IT nicardipine induces macrovascular vasodilation and reduces the risk of secondary stroke.1 However, no work has been done to assess the microvascular effects of IT nicardipine. Herein, we utilize diffuse correlation spectroscopy (DCS) to characterize the microvascular cerebral blood flow (CBF) response to IT nicardipine in a cohort of medium-high grade non-traumatic SAH patients. We hypothesize that (1) the first dose of IT nicardipine will increase microvascular CBF from pre-administration levels and that these changes will be detectable by DCS and (2) the CBF response to IT nicardipine will reach a steady state by day 3 of treatment.MethodsTwenty medium-high grade non-traumatic SAH patients were enrolled. Longitudinal DCS monitoring was performed before, during, and for up to 2h after IT nicardipine administration on days 1,2, and 3 by securing a DCS sensor2 on the forehead of the hemisphere with the vasospasm. To calculate a relative change in CBF (rCBF(t)), the DCS blood flow index (BFI) time series was normalized to the mean BFI in the 5 minutes immediately prior to nicardipine. BFI was compared to TCD mean velocities taken on the same day.ResultsDCS BFI was significantly correlated with mean TCD velocities (rs=0.68,p=0.001, figure 1a). CBF increased significantly after IT nicardipine administration on days 1 and 2 (p<0.001, figure 1b). By the third day, CBF was reduced, suggesting that nicardipine had reached a steady state concentration in the brain. Given the heterogeneous CBF response to the first dose, we used a latent class mixture model to identify two distinct classes of CBF response; patients in Class 1 (n=13, figure 1c) exhibited a steady rCBF increase, whereas patients in Class 2 (n=5, figure 1c) showed minimal rCBF change. The DCI frequency at 1 month was significantly different between classes (p<0.001).Abstract LB006 Figure 1(a) Relationship between DCS-measured BFI and TCD-measured mean blood flow velocity in the MCA (cm/s) (n= 19 rs = 0.68, p = 0.0012) (b) Mean ± standard error in cerebral blood flow (rCBF,%) as a function of time post-IT nicardipine administration (given at t=0, denoted by vertical black line). rCBF is shown for the first 3 days of treatment. (c) rCBF (%) as a function of time after the first dose of nicardipine. Here, thin lines denote individual patient responses, while thick lines denote the model best fit for each response class identified by the latent class mixture model: Class 1 (n = 13, in green) exhibited an increase in rCBF over the course of monitoring, whereas Class 2 (n=5, in red) showed minimal change in rCBF post-nicardipineDiscussionOur results suggest that IT nicardipine achieves the desired effect of microvascular vasodilation in the majority of patients after the first dose of treatment, while those patients who did not respond developed a secondary stroke. DCS may be a powerful tool to monitor the therapeutic efficacy of nicardipine treatment and to better guide clinical decisions for reducing secondary stroke incidence.Referencesdoi:10.3171/2020.12.jns203673doi:10.1117/1.nph.6.3.035006Disclosures E. Sathialingam: None. K. Cowdrick: None. A. Liew: None. F. Akbik: None. O. Samuels: None. P. Kandiah: None. O. Sadan: None. E. Buckley: None.
BackgroundAneurysmal subarachnoid hemorrhage is a devastating neurological condition which requires complex neurocritical care and neurosurgical decision-making and results in remarkably variable ...outcomes. Robust methods of identifying patients who may need operative or critical care intervention, such as those who develop hydrocephalus requiring long term shunting, cerebral vasospasm and delayed cerebral ischemia, or patients with worsened neurological outcome, are lacking.MethodsTo this end, we applied artificial neural networks and machine learning techniques to a curated aneurysmal subarachnoid hemorrhage database collected at a large academic medical center between 2015–2020, (n = 855).ResultsUsing this data, we have generated artificial neural network models with hyperparameter tuning which predict the need for long-term cerebrospinal fluid (CSF) diversion via placement of a shunt (receiver operating characteristic area under the curve (ROC AUC) = 0.9916), delayed cerebral ischemia (ROC AUC = 0.9903), and vasospasm (ROC AUC = 0.9834) from information available during the first few days of a patient’s admission. This data included demographic and medical history information including gender, age, race, Hunt and Hess Scale, hypertension, diabetes, smoking, coronary artery disease, dyslipidemia, and the category of aneurysmal treatment. Additionally, external ventricular drainage variables such as external ventricular drain (EVD) output, EVD level, EVD age, and CSF parameters, such as CSF protein level, were used. The models were trained on a subpopulation of 80% of subjects and then individually validated in the withheld 20% of subjects with high reproducibility and accuracy. Finally, using the same data, another model was generated which accurately predicted categorical disposition at time of discharge (home, subacute rehabilitation, acute rehabilitation, long-term acute care, expiration in hospital) (ROC AUC = 0.9934).ConclusionWe hope the use of artificial intelligence and machine learning techniques will continue to demonstrate power in predicting complex medical outcomes and ultimately help neurosurgeons and neuro-critical care personnel to provide appropriate and timely treatment.Disclosures T. Steed: None. A. Alawieh: None. F. Akbik: None. O. Sadan: None. O. Samuels: None. J. Grossberg: 1; C; Grant: GRA, EMCF, Neurosurgery Catalyst. 2; C; Cognition.
We examined twenty-one patients in whom an established nonunion of the scaphoid had been treated with Herbert-screw fixation with bone-grafting; our purpose was to determine the long-term morbidity ...of the procedure (at an average of forty-eight months; range, seventeen to fifty-five months). According to the modified scaphoid outcome scoring system, eighteen patients had a good or excellent result. No patient had failure of the hardware. Radial deviation was significantly decreased (an average of 17 degrees; 55 percent) compared with that of the contralateral wrist (p = 0.02). The other ranges of motion and the grip strength were also decreased, although the difference was not found to be significant with the numbers available. Three patients had a persistent nonunion, and two of them also had loosening of the hardware. Three patients had a tender hypertrophic scar. On the basis of our data, we concluded that Herbert-screw fixation with bone-grafting is effective for the treatment of nonunion of the scaphoid.
IntroductionOptimal timing of intervention after aneurysmal subarachnoid hemorrhage (aSAH) remains unclear. Practices vary from urgent/early intervention within a day of presentation to ...emergent/ultra-early occlusion upon presentation. While emergent intervention aims to minimize re-ruptures, this must be weighed against increased procedural risks and resource utilization. Here we compare the clinical course and outcomes of patients presenting during regular versus after-hours to determine whether timing of presentation drives disparities in outcomes.MethodsWe performed a retrospective cohort study of aSAH patients admitted to a tertiary care center between January 1, 2012 through March 31, 2019. Patients were grouped based on the time of presentation during regular hours (0700hrs-1700hrs) vs. after-hours (1700hrs-0700hrs). Local practice for same-day intervention where feasible for regular hours presentation, patients presenting after-hours undergo treatment as the first case the following morning. Patients requiring emergent surgical decompression were excluded from analysis. Prospectively defined baseline characteristics, timing intervals, and clinical outcomes were compared.Results415 patients were included for analysis, 145 (34.9%) presenting during regular hours and 270 (65.1%) presenting during after-hours. Baseline demographics, latency to presentation, and severity of presentation where comparable between groups. Latency from presentation to initial angiography was shorter for regular versus after-hours presentations, with 30.3% vs. 14.% undergoing angiography within 4 hours of arrival (p<0.001). 71.2% vs. 74.0% underwent endovascular embolization. Aneurysmal re-rupture was rare in both cohorts (1.5% vs. 0.8%, not significant). Complications including cerebral vasospasm (52.4% vs. 52.8%, not significant) and radiographic delayed cerebral ischemia (DCI, 15.9% vs. 11.4%, p=0.070) were similar between cohorts, although there was a non-significant trend towards decreased DCI with after-hours presentation. In-hospital mortality and rates of good functional outcomes (defined as modified Rankin score of 0–2 at 1–6 months post discharge), were comparable between groups. After-hours presentation did not correlate with good functional outcome in multivariable binary logistic regression analyses accounting for age, latency from ictus, latency from admission to angiography, Hunt and Hess grade, Fisher grade, and smoking (aOR 0.83 0.55 - 1.25, p=0.368).Abstract E-011 Figure 1ConclusionsIn this retrospective cohort study, timing of presentation did not correlate with in-hospital complications or long-term functional outcomes after aSAH. Although aneurysmal re-rupture is front-loaded in the ultra-early window, it is likely that this window has already passed by the time patients ultimately filter into a tertiary referral center. A practice of urgent and not-emergent aneurysmal occlusion did not lead to disparities in outcomes for patients presenting after-hours.Disclosures F. Akbik: None. L. Ermias: None. K. Williams: None. O. Takieddin: None. J. Grossberg: None. F. Tong: None. C. Cawley: None. O. Samuels: None. O. Sadan: None. B. Howard: None.
We describe four cases in which abciximab was used as a thrombolytic rescue agent in the setting of thrombotic events complicating interventional neuroradiologic procedures. After IV administration ...of abciximab, the thrombus resolved within 30 min in three cases, whereas no thrombolysis occurred in the fourth case despite the addition of intraarterial tissue plasminogen activator. Further evaluation of glycoprotein IIb-IIIa inhibitors in patients with cerebral thromboembolic events is necessary to prove clinical efficacy.
Introduction: From 2004–2012, the Harvard/AIDS Prevention Initiative in Nigeria, funded through the US President’s Emergency Plan for AIDS Relief programme, scaled up HIV care and treatment services ...in Nigeria. We describe the methodologies and collaborative processes developed to improve laboratory capacity significantly in a resource-limited setting. These methods were implemented at 35 clinic and laboratory locations.Methods: Systems were established and modified to optimise numerous laboratory processes. These included strategies for clinic selection and management, equipment and reagent procurement, supply chains, laboratory renovations, equipment maintenance, electronic data management, quality development programmes and trainings.Results: Over the eight-year programme, laboratories supported 160 000 patients receiving HIV care in Nigeria, delivering over 2.5 million test results, including regular viral load quantitation. External quality assurance systems were established for CD4+ cell count enumeration, blood chemistries and viral load monitoring. Laboratory equipment platforms were improved and standardised and use of point-of-care analysers was expanded. Laboratory training workshops supported laboratories toward increasing staff skills and improving overall quality. Participation in a World Health Organisation-led African laboratory quality improvement system resulted in significant gains in quality measures at five laboratories.Conclusions: Targeted implementation of laboratory development processes, during simultaneous scale-up of HIV treatment programmes in a resource-limited setting, can elicit meaningful gains in laboratory quality and capacity. Systems to improve the physical laboratory environment, develop laboratory staff, create improvements to reduce costs and increase quality are available for future health and laboratory strengthening programmes. We hope that the strategies employed may inform and encourage the development of other laboratories in resource-limited settings.
PDF
