| 1. |
- Borota, Ljubisa, et al.
(författare)
-
Combined percutaneous and transarterial devascularisation of juvenile nasopharyngeal angiofibroma with protection of internal carotid artery : A modification of the technique
- 2015
-
Ingår i: Interventional Neuroradiology. - : SAGE Publications. - 1591-0199 .- 2385-2011. ; 21:3, s. 390-396
-
Tidskriftsartikel (refereegranskat)abstract
- Juvenile nasal angiofibroma (JNA) is a hypervascularised, benign, but locally aggressive tumour that grows in the posterior, upper part of the nasal cavity and invades surrounding anatomical structures. The treatment of choice is surgical removal, but complete resection of the tumour can be hampered because of profuse perioperative bleeding. Preoperative embolisation of the tumour has been proposed as an effective method for prevention of perioperative bleeding, thereby shortening of the time of the operation. In this report of five cases, we describe successful preoperative devascularisation of the tumour by applying a modified method of direct intratumoural injection of the liquid embolic agent Onyx combined with protection of the internal carotid artery. The control of bleeding during the embolisation and occlusion of the maxillary or sphenopalatine artery was achieved by using a bi-luminal balloon catheter. Such use of the dual-lumen catheter in treatment of JNA has not been reported so far in the medical literature.
|
|
| 2. |
- Borota, Ljubisa, et al.
(författare)
-
Dual lumen balloon catheter - An effective substitute for two single lumen catheters in treatment of vascular targets with challenging anatomy
- 2018
-
Ingår i: Journal of clinical neuroscience. - : Elsevier BV. - 0967-5868 .- 1532-2653. ; 51, s. 91-99
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to describe our experience in the treatment of various pathological conditions of the cranial and spinal blood vessels and hypervascularized lesions using dual lumen balloon catheters. Twenty-five patients were treated with endovascular techniques: two with vasospasm of cerebral blood vessels caused by subarachnoid hemorrhage, one with a hypervascularized metastasis in the vertebral body, two with spinal dural fistula, four with cerebral dural fistula, three with cerebral arteriovenous malformations, and 13 with aneurysms. The dual lumen balloon catheters were used for remodeling of the coil mesh, injection of various liquid embolic agents, particles and nimodipine, for the prevention of reflux and deployment of coils and stents. The diameter of catheterized blood vessels varied from 0.7 mm to 4 mm. Two complications occurred: perforation of an aneurysm in one case and gluing of the tip of balloon catheter by embolic material in another case. All other interventions were uneventful, and therapeutic goals were achieved in all cases except in the case with gluing of the tip of balloon catheter. The balloons effectively prevented reflux regardless of the type of the embolic material and diameter of blood vessel. The results of our study show that dual lumen balloon catheters allow complex interventions in the narrow cerebral and spinal blood vessels where the safe use of two single lumen catheters is either limited or impossible.
|
|
| 3. |
- Borota, Ljubisa, et al.
(författare)
-
Endovascular treatment of type 1 and type 4 non-saccular aneurysms of cerebral arteries : a single-Centre experience
- 2021
-
Ingår i: Interventional Neuroradiology. - : Sage Publications. - 1591-0199 .- 2385-2011. ; 27:3, s. 372-387
-
Tidskriftsartikel (refereegranskat)abstract
- AIM OF THE STUDY: The aim of this study was to evaluate our results regarding treatment options, complications, and outcomes in patients with non-saccular aneurysms of cerebral arteries belonging to type 1 and type 4 according to Mizutani's classification.METHODS: A total of 26 aneurysms in 26 patients were treated between 2014 and 2019. There were 13 males (mean age 42.77 ± 11.73 years) and 13 females (mean age 50.84 ± 9.37 years). In 23 cases the onset was haemorrhagic and in three cases non-haemorrhagic. A combination of conventional stents and coils was used in 10 cases, conventional stents and flow diverters in three cases, flow diverters and coils in five cases, and flow diverters only were used in eight cases. Radiological results of treatment were assessed after eight months and clinical after one year.RESULTS: In 24 patients, aneurysms were occluded at the end of the follow-up period. An iatrogenic dissection and two haemorrhagic complications were registered. In three cases, parent arteries were occluded due to re-growth of the aneurysm, which caused middle cerebral artery infarction in one case. A favourable clinical outcome was registered in 19, patients, and non-favourable in five. Two patients died in the early postoperative period due to extensive damage to the brain parenchyma caused by initial bleeding.CONCLUSION: Our results indicate that treatment of type 1 and type 4 non-saccular aneurysms with various combination of stents and flow diverters, with or without coils, is promising, although very challenging and technically demanding.
|
|
| 4. |
- Borota, Ljubisa, et al.
(författare)
-
Expanded range of indications for Neuroform Atlas stent in the treatment of very small, wide-necked cerebral aneurysms
- 2023
-
Ingår i: Journal of clinical neuroscience. - : Elsevier. - 0967-5868 .- 1532-2653. ; 114, s. 38-47
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the range of indications for using the Neuroform Atlas stent. Between 2016 and 2020, we treated 20 females and 5 males for aneurysms with a diameter of less than 3 mm and an aspect ratio less than 1.5. The diameter of the parent arteries varied from 1.1 mm to 4.5 mm. There were 13 ruptured and 12 unruptured aneurysms. Double stent-assisted coiling was performed in 14 cases, and single stent-assisted coiling was performed in 11 cases. After deployment, the morphology of the Neuroform Atlas stents was analyzed in tapered or Y-shaped silicone tubes that simulated parent arteries. Radiological results were assessed 7 months and 2 years after the intervention using the Raymond-Roy scale. Clinical outcome was assessed 1 year after the intervention using the modified Rankin score. There were three fatal outcomes. One aneurysm was recoiled. The rate of class I aneurysm occlusion was registered in 21 patients at the last follow-up. At the end of the clinical follow-up period, a favorable outcome (modified Rankin scale 0 -1) was registered in nine patients with ruptured aneurysms. An analysis of the morphology of the stents deployed in the silicone tubes provided an explanation for the stability of the coil mass in the treated aneurysms. Our results suggest that the range of indications for use of the Neuroform Atlas stent can be expanded beyond the present range with regard to the diameter of the parent vessels and size of the aneurysms.
|
|
| 5. |
- Borota, Ljubisa, et al.
(författare)
-
Neuroform Atlas stent in treatment of iatrogenic dissections of extracranial internal carotid and vertebral arteries : a single-centre experience
- 2019
-
Ingår i: Interventional Neuroradiology. - : SAGE Publications. - 1591-0199 .- 2385-2011. ; 25:4, s. 390-396
-
Tidskriftsartikel (refereegranskat)abstract
- AIM OF THE STUDY: To present our experience in the treatment of iatrogenic dissections of extracranial internal carotid and vertebral arteries with the Neuroform Atlas stent.MATERIALS AND METHODS: Between January 2017 and February 2018 we treated iatrogenic dissections of three internal carotid arteries and three vertebral arteries. These iatrogenic dissections occurred during the endovascular treatment of ruptured and unruptured intracranial aneurysms. The indication for stenting was haemodynamically significant, flow-limiting dissection with threatening flow arrest. In all six cases, the dissections were treated by placement of Neuroform Atlas stents in the dissected segments of internal carotid or vertebral arteries. Deployment of the stent was followed by the usual dual antiplatelet regimen.RESULTS: Single or multiple Neuroform Atlas stents were deployed without any technical difficulties, and blood flow was restored immediately after placement of the stents in all six cases. Midterm follow-up (6-8 months) showed complete reconstruction of the shape and lumen of all treated arteries, with negligible intimal hyperplasia.CONCLUSION: Our results indicate that a favourable outcome can be achieved by treating iatrogenic dissections of extracranial internal carotid and vertebral arteries with the Neuroform Atlas stent.
|
|
| 6. |
- Borota, Ljubisa, et al.
(författare)
-
Spot fluoroscopy : a novel innovative approach to reduce radiation dose in neurointerventional procedures
- 2017
-
Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 58:5, s. 600-608
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Increased interest in radiation dose reduction in neurointerventional procedures has led to the development of a method called "spot fluoroscopy" (SF), which enables the operator to collimate a rectangular or square region of interest anywhere within the general field of view. This has potential advantages over conventional collimation, which is limited to symmetric collimation centered over the field of view.PURPOSE: To evaluate the effect of SF on the radiation dose.MATERIAL AND METHODS: Thirty-five patients with intracranial aneurysms were treated with endovascular coiling. SF was used in 16 patients and conventional fluoroscopy in 19. The following parameters were analyzed: the total fluoroscopic time, the total air kerma, the total fluoroscopic dose-area product, and the fluoroscopic dose-area product rate. Statistical differences were determined using the Welch's t-test.RESULTS: The use of SF led to a reduction of 50% of the total fluoroscopic dose-area product (CF = 106.21 Gycm(2), SD = 99.06 Gycm(2) versus SF = 51.80 Gycm(2), SD = 21.03 Gycm(2), p = 0.003884) and significant reduction of the total fluoroscopic dose-area product rate (CF = 1.42 Gycm(2)/min, SD = 0.57 Gycm(2)/s versus SF = 0.83 Gycm(2)/min, SD = 0.37 Gycm(2)/min, p = 0.00106). The use of SF did not lead to an increase in fluoroscopy time or an increase in total fluoroscopic cumulative air kerma, regardless of collimation.CONCLUSION: The SF function is a new and promising tool for reduction of the radiation dose during neurointerventional procedures.
|
|
| 7. |
- Carvalho, Ricardo, 1985-, et al.
(författare)
-
Household Bioenergy Transitions with Alternative Biomass Feedstocks and Technologies: An Integrated System to Mitigate Environmental Risks in Western Kenya
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In Kenya, over 50% of the total primary energy consumption is from traditional solid-fuel cooking, being this a major cause of deforestation and household air pollution (HAP). Western Kenya has an agricultural biofuel feedstock of over 1.9 million Mt, which could be processed to supply cookstoves with crop-residue pellets and improved wood fallows. The sociotechnical viability of two novel bioenergy value chains were analysed using the Long-Range Energy Alternatives Planning system. Three scenarios of transition to efficient cookstoves and decentralized biofuel and electricity production systems were tested. In the “Optimal scenario”, the current feedstock in the Kisumu and Siaya counties could satisfy over 80% of the cooking energy demand by 2030. Here, the net greenhouse gas emissions from charcoal production and HAP could be reduced by 87% to 12.6 thousand Mt CO2e. Further work should integrate socioeconomic indicators reflecting additional local/regional stakeholders´ collaboration channels (cost-effective) to support the bioenergy transitions.
|
|
| 8. |
- Carvalho, Ricardo L., et al.
(författare)
-
Bioenergy strategies to address deforestation and household air pollution in western Kenya
- 2019
-
Ingår i: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 1536-1542
-
Konferensbidrag (refereegranskat)abstract
- Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden disease due to household air pollution. The Long-Range Energy Alternatives Planning (LEAP) system and the Life-Cycle Assessment tool Simapro 8.5 were applied for analyzing biomass strategies for the region. The calculation of the residential energy consumption and emissions was based on scientific reviews and original data from experimental studies. The research shows the effect of four biomass strategies on the reduction of wood fuel use and short-lived climate pollutant emissions. A Business As Usual scenario (BAU) considered the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) considered the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluated a mix of the ICS, PGS and BGS. The study shows that, energy use will increase by 8% (BGS), 20% (INT), 26% (PGS), 42% (ICS) and 56% (BAU). The BGS has the lowest impact on global warming, particle formation, terrestrial acidification, fossil resource scarcity, water consumption, as well as on eutrophication followed by the PGS and INT.
|
|
| 9. |
- Carvalho, Ricardo Luís, et al.
(författare)
-
Environmental Sustainability of Bioenergy Strategies in Western Kenya to Address Household Air Pollution
- 2020
-
Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:3
-
Tidskriftsartikel (refereegranskat)abstract
- Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden of disease due to household air pollution. Efficient biomass cooking is a local-based renewable energy solution to address this issue. The Life-Cycle Assessment tool Simapro 8.5 is applied for analyzing the environmental impact of four biomass cooking strategies for the Kisumu County, with analysis based on a previous energy modelling study, and literature and background data from the Ecoinvent and Agrifootprint databases applied to the region. A Business-As-Usual scenario (BAU) considers the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) consider the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluates a mix of the ICS, PGS and BGS. In the BGS, the available biomass waste is sufficient to be upcycled and fulfill cooking demands by 2035. This scenario has the lowest impact on all impact categories analyzed followed by the PGS and INT. Further work should address a detailed socio-economic analysis of the analyzed scenarios.
|
|
| 10. |
- Carvalho, Ricardo L., et al.
(författare)
-
Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya
- 2019
-
Ingår i: Energy Policy. - : Elsevier. - 0301-4215 .- 1873-6777. ; 131, s. 168-186
-
Tidskriftsartikel (refereegranskat)abstract
- Traditional cooking is today's largest global environmental health risk. Over 640 million people in Africa are expected to rely on biomass for cooking by 2040. In Kenya, cooking inefficiently with wood and charcoal persists as a cause of deforestation and household air pollution. This research analyses the effects of four biomass cookstove strategies on reducing air pollutant emissions in Kisumu County between 2015 and 2035 using the Long-Range Energy Alternatives Planning system. The Business as Usual scenario (BAU) was developed considering the historical trends in household energy use. Energy transition scenarios to Improved Cookstoves (ICS), Pellet Gasifier Stoves (PGS) and Biogas Stoves (BGS) were applied to examine the impact of these systems on energy savings and air pollution mitigation. An integrated scenario (INT) was evaluated as a mix of the ICS, PGS and BGS. The highest energy savings, in relation to the BAU, are achieved in the BGS (30.9%), followed by the INT (23.5%), PGS (19.4%) and ICS (9.2%). The BGS offers the highest reduction in the GHG (37.6%), CH4 (94.3%), NMVOCs (85.0%), CO (97.4%), PM2.5 (64.7%) and BC (48.4%) emissions, and the PGS the highest reduction in the N2O (83.0%) and NOx (90.7%) emissions, in relation to the BAU.
|
|
| 11. |
- Dvirnas, Albertas, et al.
(författare)
-
Facilitated sequence assembly using densely labeled optical DNA barcodes: A combinatorial auction approach
- 2018
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:3
-
Tidskriftsartikel (refereegranskat)abstract
- The output from whole genome sequencing is a set of contigs, i.e. short non-overlapping DNA sequences (sizes 1-100 kilobasepairs). Piecing the contigs together is an especially difficult task for previously unsequenced DNA, and may not be feasible due to factors such as the lack of sufficient coverage or larger repetitive regions which generate gaps in the final sequence. Here we propose a new method for scaffolding such contigs. The proposed method uses densely labeled optical DNA barcodes from competitive binding experiments as scaffolds. On these scaffolds we position theoretical barcodes which are calculated from the contig sequences. This allows us to construct longer DNA sequences from the contig sequences. This proof-of-principle study extends previous studies which use sparsely labeled DNA barcodes for scaffolding purposes. Our method applies a probabilistic approach that allows us to discard "foreign" contigs from mixed samples with contigs from different types of DNA. We satisfy the contig non-overlap constraint by formulating the contig placement challenge as a combinatorial auction problem. Our exact algorithm for solving this problem reduces computational costs compared to previous methods in the combinatorial auction field. We demonstrate the usefulness of the proposed scaffolding method both for synthetic contigs and for contigs obtained using Illumina sequencing for a mixed sample with plasmid and chromosomal DNA.
|
|
| 12. |
- García-López, Naxto, et al.
(författare)
-
An integrated agroforestry-bioenergy system for enhanced energy and food security in rural sub-Saharan Africa
- 2024
-
Ingår i: Ambio. - 0044-7447 .- 1654-7209.
-
Tidskriftsartikel (refereegranskat)abstract
- Most people in rural sub-Saharan Africa lack access to electricity and rely on traditional, inefficient, and polluting cooking solutions that have adverse impacts on both human health and the environment. Here, we propose a novel integrated agroforestry-bioenergy system that combines sustainable biomass production in sequential agroforestry systems with biomass-based cleaner cooking solutions and rural electricity production in small-scale combined heat and power plants and estimate the biophysical system outcomes. Despite conservative assumptions, we demonstrate that on-farm biomass production can cover the household’s fuelwood demand for cooking and still generate a surplus of woody biomass for electricity production via gasification. Agroforestry and biochar soil amendments should increase agricultural productivity and food security. In addition to enhanced energy security, the proposed system should also contribute to improving cooking conditions and health, enhancing soil fertility and food security, climate change mitigation, gender equality, and rural poverty reduction.
|
|
| 13. |
- Mahmoud, Ehab, et al.
(författare)
-
Use of Distal Intracranial Catheters for Better Working View of Cerebral Aneurysms Hidden by Parent Artery or Its Branches : A Technical Note
- 2021
-
Ingår i: Neurointervention. - : Korean Society of Interventional Neuroradiology. - 2093-9043 .- 2233-6273. ; 16:3, s. 267-274
-
Tidskriftsartikel (refereegranskat)abstract
- A good working view is critical for safe and successful endovascular treatment of cerebral aneurysms. In a few cases, endovascular treatment of cerebral aneurysms may be challenging due to difficulty in obtaining a proper working view. In this report of 6 cases, we described the advantage of using a distal intracranial catheter (DIC) to achieve better visualization of cerebral aneurysms hidden by a parent artery or its branches. Between September 2017 and January 2021, we treated 390 aneurysms with endovascular techniques. In 6 cases in which it was difficult to obtain a proper working view, the DIC was placed distally close to the aneurysm in order to remove the parent artery projection from the working view and obtain better visualization of the aneurysm. Clinical and procedural outcomes and complications were evaluated. The position of the DIC was above the internal carotid artery siphon in the 6 cases. All aneurysms were successfully embolized. Raymond-Roy class 1 occlusion was achieved in all 4 unruptured aneurysms, while the result was class 2 in the 2 ruptured aneurysms. Placement of the DIC was atraumatic without dissections or significant catheter-induced vasospasm in all patients. Transient dysphasia was seen in 2 cases and transient aphasia in 1. Using this technique, we have found it possible to better visualize the aneurysm sac or neck and thereby treat cases we otherwise would have considered untreatable.
|
|
| 14. |
- Müller, Vilhelm, 1990, et al.
(författare)
-
Rapid Tracing of Resistance Plasmids in a Nosocomial Outbreak Using Optical DNA Mapping
- 2016
-
Ingår i: Acs Infectious Diseases. - : American Chemical Society (ACS). - 2373-8227. ; 2:5, s. 322-328
-
Tidskriftsartikel (refereegranskat)abstract
- Resistance to life-saving antibiotics increases rapidly worldwide, and multiresistant bacteria have become a global threat to human health. Presently, the most serious threat is the increasing spread of Enterobacteriaceae carrying genes coding for extended spectrum beta-lactamases (ESBL) and carbapenemases on highly mobile plasmids. We here demonstrate how optical DNA maps of single plasmids can be used as fingerprints to trace plasmids, for example, during resistance outbreaks. We use the assay to demonstrate a potential transmission route of an ESBL-carrying plasmid between bacterial strains/species and between patients, during a polyclonal outbreak at a neonatal ward at Sahlgrenska University Hospital (Gothenburg, Sweden). Our results demonstrate that optical DNA mapping is an easy and rapid method for detecting the spread of plasmids mediating resistance. With the increasing prevalence of multiresistant bacteria, diagnostic tools that can aid in solving ongoing routes of transmission, in particular in hospital settings, will be of paramount importance.
|
|
| 15. |
|
|
| 16. |
- Nyberg, Christoffer, et al.
(författare)
-
Daily systemic energy expenditure in the acute phase of aneurysmal subarachnoid hemorrhage
- 2019
-
Ingår i: Upsala Journal of Medical Sciences. - : TAYLOR & FRANCIS LTD. - 0300-9734 .- 2000-1967. ; 124:4, s. 254-259
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with subarachnoid hemorrhage often have impaired consciousness and cannot regulate nutritional intakes themselves. Previous studies have demonstrated elevated energy expenditure in the acute phase, but it is not known whether the energy demand is constant during the first week after onset of the disease. In this study, we performed daily measurements of energy expenditure with indirect calorimetry during the first 7 days after aneurysmal subarachnoid hemorrhage in mechanically ventilated patients.Methods: Metabolic measurements were performed daily with indirect calorimetry in 26 patients with aneurysmal subarachnoid hemorrhage. All patients were intubated and mechanically ventilated. The measured value was compared to the predicted values from the Harris-Benedict equation and the Penn State University 1998 equation. Urinary nitrogen excretion was measured daily.Results: There was a significant increase in energy expenditure during days 2-3 compared to days 5-6. The Harris-Benedict equation underestimated metabolic demand. The Penn State 1998 equation was closer to the measured values, but still underestimated caloric need. Urinary nitrogen excretion increased throughout the first week from initially low values.Conclusions: There is a dynamic course in energy expenditure in patients with aneurysmal subarachnoid hemorrhage, with increasing metabolic demand during the first week of the disease. Indirect calorimetry could be used more often to help provide an adequate amount of energy.
|
|
| 17. |
- Nyberg, Christoffer, 1977-
(författare)
-
Metabolic and Endocrine Response in the Acute Stage of Subarachnoid Hemorrhage
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The rupture of an aneurysm in subarachnoid hemorrhage (SAH) is a dramatic event causing a severe impact on the brain and a transient or permanent ischemic condition. Several types of responses to meet the challenges of SAH have been found in the acute phase, including activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system, elevated levels of brain natriuretic peptide (BNP), and disturbances in cerebral and systemic metabolism.Cerebral metabolism and the endocrine stress response in the ultra-early phase was investigated in a novel porcine model of SAH in which autologous blood was injected to the anterior skull base. Early activation of the HPA axis was found with rapid elevation of adrenocorticotrophic hormone, cortisol and aldosterone. The peak values of these hormones were early and may be impossible to catch in patients. There were indications of a sympathetic nervous response with excretion of catecholamines in urine as well as plasma chromogranin-A elevation. Cerebral microdialysis suggested immediate substrate failure followed by hypermetabolism of glucose. The animal model seems suited for further studies of aneurysmal SAH.NT-proBNP was investigated in 156 patients with SAH, there was a dynamic course with increasing levels during the first 4 days of the disease. Factors predicting high NT-proBNP load included female sex, high age, high Troponin-I at admission, angiographic finding of an aneurysm and worse clinical condition at admission. High levels of NT-proBNP were correlated to factors indicating a more severe disease, suggesting the initial injury in aneurysmal SAH is an important factor in predicting high NT-proBNP during the acute stage of the disease.Measurements with indirect calorimetry were performed daily during the first week after SAH on 32 patients with SAH. There was a dynamic course with increasing energy expenditure (EE) the first week after SAH. Comparisons with three predictive equations indicated that measured EE generally is higher than predicted, but considerable variation exists within and between patients, indicating that prediction of EE in SAH is difficult.Altogether, the studies demonstrate a complicated response in acute SAH that needs to be further studied to increase possibility of good outcome in SAH patients.
|
|
| 18. |
- Nyberg, Christoffer, et al.
(författare)
-
Metabolic Pattern of the Acute Phase of Subarachnoid Hemorrhage in a Novel Porcine Model : Studies with Cerebral Microdialysis with High Temporal Resolution
- 2014
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:6, s. e99904-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Aneurysmal subarachnoid hemorrhage (SAH) may produce cerebral ischemia and systemic responses including stress. To study immediate cerebral and systemic changes in response to aneurysm rupture, animal models are needed. Objective: To study early cerebral energy changes in an animal model. Methods: Experimental SAH was induced in 11 pigs by autologous blood injection to the anterior skull base, with simultaneous control of intracranial and cerebral perfusion pressures. Intracerebral microdialysis was used to monitor concentrations of glucose, pyruvate and lactate. Results: In nine of the pigs, a pattern of transient ischemia was produced, with a dramatic reduction of cerebral perfusion pressure soon after blood injection, associated with a quick glucose and pyruvate decrease. This was followed by a lactate increase and a delayed pyruvate increase, producing a marked but short elevation of the lactate/pyruvate ratio. Glucose, pyruvate, lactate and lactate/pyruvate ratio thereafter returned toward baseline. The two remaining pigs had a more severe metabolic reaction with glucose and pyruvate rapidly decreasing to undetectable levels while lactate increased and remained elevated, suggesting persisting ischemia. Conclusion: The animal model simulates the conditions of SAH not only by deposition of blood in the basal cisterns, but also creating the transient global ischemic impact of aneurysmal SAH. The metabolic cerebral changes suggest immediate transient substrate failure followed by hypermetabolism of glucose upon reperfusion. The model has features that resemble spontaneous bleeding, and is suitable for future research of the early cerebral and systemic responses to SAH that are difficult to study in humans.
|
|
| 19. |
- Nyberg, Christoffer, et al.
(författare)
-
Predictors of increased cumulative serum levels of the N-terminal prohormone of brain natriuretic peptide 4 days after acute spontaneous subarachnoid hemorrhage
- 2014
-
Ingår i: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 120:3, s. 599-604
-
Tidskriftsartikel (refereegranskat)abstract
- Object. The rupture of an intracranial aneurysm is followed by increased intracranial pressure and decreased cerebral blood flow. A major systemic stress reaction follows, presumably to restore cerebral blood flow. However, this reaction can also cause adverse effects, including myocardial abnormalities, which are common and can be serious, and increased levels of natriuretic peptides, especially brain natriuretic peptide (BNP). The association of BNP with fluid and salt balance, vasospasm, brain ischemia, and cardiac injury has been studied but almost exclusively regarding events after admission. Brain natriuretic peptide has also been measured at various time points and analyzed in different ways statistically. The authors approached BNP measurement in a new way; they used the calculated area under the curve (AUC) for the first 4 days to quantitatively measure the BNP load during the first critical part of the disease state. Their rationale was a suspicion that early BNP load is a marker of the severity of the ictus and will influence the subsequent course of the disease by disturbing the fluid and salt balance. Methods. The study included 156 patients with acute spontaneous subarachnoid hemorrhage (SAH). Mean patient age was 59.8 +/- 11.2 years, and 105 (67%) of the patients were female. An aneurysm was found in 138 patients. A total of 82 aneurysms were treated by endovascular coiling, 50 were treated by surgery, and 6 were untreated. At the time of admission, serum samples were collected for troponin-I analysis and for the N-terminal prohormone of BNP (NT-proBNP); daily thereafter, samples were collected for the NT-proBNP analysis. The cumulative BNP load was calculated as the AUC for NT-proBNP during the first 4 days. The following variables were studied in terms of their influence on the AUC for NT-proBNP: sex, age, World Federation of Neurosurgical Societies grade of SAH, Fisher grade, angiographic result, treatment of aneurysm,'clinical neurological deterioration, verified infections, vasospasm treatment, and 6-month outcome. Results. The AUC for NT-proBNP was larger when variables indicated a more severe SAH. These variables were higher Fisher and World Federation of Neurosurgical Societies grades, high levels of troponin-I at admission, an aneurysm, neurological deficits, and infections. The AUC for NT-proBNP was also larger among women, older patients, and patients with poor outcomes. Linear regression showed that the best predicting model for large AUC for NT-proBNP was the combination of the following: female sex, high levels of troponin-I, an aneurysm, neurological deficits, and advanced age. Conclusions. The cumulative BNP load during the first days after SAH can be predicted by variables describing the severity of the disease already known at the time of admission. This information can be used to identify patients at risk for an adverse course of the disease.
|
|
| 20. |
- Nyberg, Christoffer, et al.
(författare)
-
The Early Endocrine Stress Response in Experimental Subarachnoid Hemorrhage
- 2016
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:3
-
Tidskriftsartikel (refereegranskat)abstract
- IntroductionIn patients with severe illness, such as aneurysmal subarachnoid hemorrhage (SAH), a physiologic stress response is triggered. This includes activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system. The aim of this study was to investigate the very early responses of these systems.MethodsA porcine animal model of aneurysmal SAH was used. In this model, blood is injected slowly to the basal cisterns above the anterior skull base until the cerebral perfusion pressure is 0 mm Hg. Sampling was done from blood and urine at -10, +15, +75 and +135 minutes from time of induction of SAH. Analyses of adrenocorticotropic hormone (ACTH), cortisol, aldosterone, catecholamines and chromogranin-A were performed.ResultsPlasma ACTH, serum cortisol and plasma aldosterone increased in the samples following induction of SAH, and started to decline after 75 minutes. Urine cortisol also increased after SAH. Urine catecholamines and their metabolites were found to increase after SAH. Many samples were however below detection level, not allowing for statistical analysis. Plasma chromogranin-A peaked at 15 minutes after SAH, and thereafter decreased.ConclusionsThe endocrine stress response after aneurysmal SAH was found to start within 15 minutes in the HPA axis with early peak values of ACTH, cortisol and aldosterone. The fact that the concentrations of the HPA axis hormones decreased 135 minutes after SAH may suggest that a similar pattern exists in SAH patients, thus making it difficult to catch these early peak values. There were also indications of early activation of the sympathetic nervous system, but the small number of valid samples made interpretation difficult.
|
|
| 21. |
- Nyberg, Truls, et al.
(författare)
-
Risk-aware Motion Planning for Autonomous Vehicles with Safety Specifications
- 2021
-
Ingår i: 2021 32nd IEEE Intelligent Vehicles Symposium (IV). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1016-1023
-
Konferensbidrag (refereegranskat)abstract
- Ensuring the safety of autonomous vehicles (AVs) in uncertain traffic scenarios is a major challenge. In this paper, we address the problem of computing the risk that AVs violate a given safety specification in uncertain traffic scenarios, where state estimates are not perfect. We propose a risk measure that captures the probability of violating the specification and determines the average expected severity of violation. Using highway scenarios of the US101 dataset and Responsible Sensitive Safety (RSS) as an example specification, we demonstrate the effectiveness and benefits of our proposed risk measure. By incorporating the risk measure into a trajectory planner, we enable AVs to plan minimal-risk trajectories and to quantify trade-offs between risk and progress in traffic scenarios.
|
|
| 22. |
- Ronne-Engström, Elisabeth, et al.
(författare)
-
Trends in incidence and treatments of spontaneous subarachnoid hemorrhage : a 10 year hospital based study
- 2024
-
Ingår i: Acta Neurochirurgica. - : Springer. - 0001-6268 .- 0942-0940. ; 166:1
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundImproved endovascular methods make it possible to treat complex ruptured aneurysms, but surgery is still needed in certain cases. We evaluated the effects on the clinical results of the changes in aneurysm treatment.MethodsThe study cohort was 837 patients with spontaneous subarachnoid hemorrhage (SAH) and one or multiple aneurysms, admitted to Dept of Neurosurgery, Uppsala University Hospital from 2012 to 2021. Demography, location and treatment of aneurysms, neurologic condition at admission and discharge, mortality and last tier treatment of high intracranial pressure (ICP) was evaluated. Functional outcome was measured using the Extended Glasgow Outcome Scale (GOSE) Data concerning national incidences of stroke diseases was collected from open Swedish databases.ResultsEndovascular methods were used in 666 cases (79.6%). In 111 (13.3%) with stents. Surgery was performed in 115 cases (13.7%) and 56 patients (6.7%) had no aneurysm treatment. The indications for surgery were a hematoma (51 cases, 44.3%), endovascular treatment not considered safe (47 cases, 40.9%), or had been attempted without success (13 cases, 11.3%). Treatment with stent devices increased, and with surgery decreased over time. There was a trend in decrease in hemicraniectomias over time. Both the patient group admitted awake (n = 681) and unconscious (n = 156) improved significantly in consciousness between admission and discharge. Favorable outcome (GOSE 5–8) was seen in 69% for patients admitted in Hunt & Hess I-II and 25% for Hunt & Hess III-V. Mortality at one year was 10.9% and 42.7% for those admitted awake and unconscious, respectively.The number of cases decreased during the study period, which was in line with Swedish national data.ConclusionsThe incidence of patients with SAH gradually decreased in our material, in line with national data. The treatment policy in our unit has been shifting to more use of endovascular methods. During the study period the use of hemicraniectomies decreased.
|
|
| 23. |
- Svedung Wettervik, Teodor, et al.
(författare)
-
NT-proBNP and troponin I in high-grade aneurysmal subarachnoid hemorrhage : Relation to clinical course and outcome
- 2022
-
Ingår i: Journal of critical care. - : Elsevier. - 0883-9441 .- 1557-8615. ; 72
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeTo investigate the association between two cardiac biomarkers, NT-proBNP and TnI, with intracranial pressure (ICP)−/cerebral perfusion pressure (CPP)-insults, cerebral pressure autoregulation, delayed ischemic neurological deficits (DIND), and clinical outcome after aneurysmal subarachnoid hemorrhage (aSAH).MethodsIn this retrospective study, 196 aSAH patients treated at the neurointensive care unit, Uppsala University Hospital, Sweden, 2011–2018, with ICP-monitoring and serial NT-proBNP and TnI measurements were included. The first 10 days were divided into early phase (day 1–3) and vasospasm phase (day 4–10).ResultsNT-proBNP and TnI were elevated above the reference interval at least once the first 10 days in 175 (89%) and 116 (59%) patients, respectively. In the vasospasm phase, higher NT-proBNP and TnI were associated with increased percentage of CPP below 60 mmHg. Higher TnI also correlated with more ICP-insults above 20 mmHg. NT-proBNP and TnI did not predict worse pressure autoregulation and DIND. Higher NT-proBNP and TnI were associated with mortality and unfavorable outcome in univariate, but not multivariate, analyses.ConclusionElevated NT-proBNP and TnI correlated with an increased burden of secondary ICP-/CPP-insults, but not with worse pressure autoregulation, DIND, and without independent association with clinical outcome.
|
|
