Competition and community succession link N transformation and greenhouse gas emissions in urine patches.

Nitrous oxide (N2O) is a strong greenhouse gas produced by biotic/abiotic processes directly linked to both fungal and prokaryotic communities that produce, consume or create conditions leading to its emission. In soils exposed to nitrogen (N) in the form of urea, an ecological succession is triggered resulting in a dynamic turnover of microbial populations. However, knowledge of the mechanisms controlling this succession and the repercussions for N2O emissions remain incomplete. Here, we monitored N2O production and fungal/prokaryotic community changes (via 16S and 18S amplicon sequencing) in soil microcosms exposed to urea. Contributions of microbes to emissions were determined using biological inhibitors. Results confirmed that urea leads to shifts in microbial community assemblages by selecting for certain microbial groups (fast growers) as dictated through life history strategies. Urea reduced overall community diversity by conferring dominance to specific groups at different stages in the succession. The diversity lost under urea was recovered with inhibitor addition through the removal of groups that were actively growing under urea indicating that species replacement is mediated in part by competition. Results also identified fungi as significant contributors to N2O emissions, and demonstrate that dominant fungal populations are consistently replaced at different stages of the succession. These successions were affected by addition of inhibitors which resulted in strong decreases in N2O emissions, suggesting that fungal contributions to N2O emissions are larger than that of prokaryotes.

Application methods of tracers for N2O source determination lead to inhomogeneous distribution in field plots.

Source determination of N2O has often been performed using stable isotope incubation experiments. In situ experiments with isotopic tracers are an important next step. However, the challenge is to distribute the tracers in the field as homogeneously as possible. To examine this, a bromide solution was applied as a stand-in tracer using either a watering can, a sprayer, or syringes to a relatively dry (25% gravimetric moisture content) or wet (30%) silt loam. After 1 h, samples were taken from three soil depths (0-10 cm), and analyzed for their water content and bromide concentration. The application with syringes was unsuccessful due to blocked cannulas. Therefore, further laboratory experiments were conducted with side-port cannulas. Despite a larger calculated gravimetric soil moisture difference with watering can application, more Br- tracer was recovered in the sprayer treatment, probably due to faster transport of Br- through macropore flow in the wetter conditions caused by the watering can treatment. The losses of Br- (33% for the watering can, 28% for the sprayer treatment) are equivalent to potential losses of isotopic tracer solutions. For application of 60 at% 15NH4 +, this resulted in theoretical enrichments of 44-53 at% in the upper 2.5 cm and 7-48 at% in 5-10 cm. As there was hardly any NO3 - in the soil, extrapolations for 15NO3 - calculated enrichments were 57-59 at% in the upper 2.5 cm and 26-57 at% in 5-10 cm. Overall, no method, including the side-port cannulas, was able to achieve a homogeneous distribution of the tracer. Future search for optimal tracer application should therefore investigate methods that utilize capillary forces and avoid overhead pressure. We recommend working on rather dry soil when applying tracers, as tracer recovery was larger here. Furthermore, larger amounts of tracer lead to more uniform distributions. Further studies should also investigate the importance of plant surfaces.

Pulmonary infection with Mycobacterium szulgai: A case report.

Mycobacterium szulgai is a non-tuberculous mycobacterium that is an uncommon cause of infection in humans. Risk factors for infection include immunosuppression and pre-existing lung pathology. Herein, we present a case of a 42-year-old male with chronic obstructive pulmonary disease with pulmonary infection caused by M. szulgai that was successfully treated with a regimen of rifampin, isoniazid, pyrazinamide and ethambutol for 2 months, followed by rifampin, isoniazid and azithromycin for an additional 8 months. Symptomatic and radiographic resolutions were achieved.

Impact of nitrogen compounds on fungal and bacterial contributions to codenitrification in a pasture soil.

Ruminant urine patches on grazed grassland are a significant source of agricultural nitrous oxide (N2O) emissions. Of the many biotic and abiotic N2O production mechanisms initiated following urine-urea deposition, codenitrification resulting in the formation of hybrid N2O, is one of the least understood. Codenitrification forms hybrid N2O via biotic N-nitrosation, co-metabolising organic and inorganic N compounds (N substrates) to produce N2O. The objective of this study was to assess the relative significance of different N substrates on codenitrification and to determine the contributions of fungi and bacteria to codenitrification. 15N-labelled ammonium, hydroxylamine (NH2OH) and two amino acids (phenylalanine or glycine) were applied, separately, to sieved soil mesocosms eight days after a simulated urine event, in the absence or presence of bacterial and fungal inhibitors. Soil chemical variables and N2O fluxes were monitored and the codenitrified N2O fluxes determined. Fungal inhibition decreased N2O fluxes by ca. 40% for both amino acid treatments, while bacterial inhibition only decreased the N2O flux of the glycine treatment, by 14%. Hydroxylamine (NH2OH) generated the highest N2O fluxes which declined with either fungal or bacterial inhibition alone, while combined inhibition resulted in a 60% decrease in the N2O flux. All the N substrates examined participated to some extent in codenitrification. Trends for codenitrification under the NH2OH substrate treatment followed those of total N2O fluxes (85.7% of total N2O flux). Codenitrification fluxes under non-NH2OH substrate treatments (0.7-1.2% of total N2O flux) were two orders of magnitude lower, and significant decreases in these treatments only occurred with fungal inhibition in the amino acid substrate treatments. These results demonstrate that in situ studies are required to better understand the dynamics of codenitrification substrates in grazed pasture soils and the associated role that fungi have with respect to codenitrification.

Flow diverter for endovascular treatment of intracranial mirror segment internal carotid artery aneurysms.

BACKGROUND: To evaluate the feasibility and efficacy of the pipeline embolization device in the treatment of unruptured intracranial mirror segment aneurysms. METHODS: Out of a total of 338 subjects, 14 were identified harboring a total of 32 internal carotid artery mirror segment aneurysms that were treated with the pipeline embolization device and were consecutively enrolled into our study. We collected data on patient demographics, modified Rankin scale (mRS) at admission, aneurysm characteristics, clinical outcome at discharge, 3-9 and at 12-18 months as well as angiography results at follow-up. RESULTS: Patients' mean age was 52.9 years; baseline mRS was 0 in all subjects. Pipeline embolization device placement was successful in all cases. Post-treatment mRS remained 0 in 13/14 patients. One patient experienced a small intraparenchymal hemorrhage and subarachnoid hemorrhage, associated with a frontoparietal infarction resulting in right upper extremity weakness and aphasia (post-treatment mRS 3). His mRS evaluation remained stable at the 3-9-month follow-up. Three to 9-month follow-up angiography (13/14 subjects) showed complete aneurysm occlusion in 24/30 aneurysms (80%), near complete and partial occlusion in three of 30 (10%) aneurysms each. At the 9-month follow-up, one patient experienced a complete occlusion of the anterior temporal artery branch but did not present with any clinical deficits. No mRS changes were encountered over a median 6-month follow-up period. Mid-term follow-up angiography (12-18 months) available in eight of 14 subjects showed complete aneurysm occlusion in all patients. Mild intimal hyperplasia was observed in one patient. CONCLUSIONS: Flow diversion technology can be used for the treatment of unruptured mirror segment aneurysms in selected patients.

Gender differences in cortical complexity.

Cortical complexity, a measure that quantifies the spatial frequency of gyrification and fissuration of the brain surface, has not been thoroughly characterized with respect to gender differences in the human brain. Using a new three-dimensional (3D) analytic technique with magnetic resonance imaging, we found greater gyrification in women than men in frontal and parietal regions. Increased complexity implies more cortical surface area, which may offset gender differences in brain volume and account for behavioral gender differences.

Bypass for Innominate Artery Occlusive Disease.

The innominate artery, also known as the brachiocephalic artery, is the first vessel off the aortic arch and provides blood to the right arm, neck, and head. Occlusion of the innominate artery can be treated with endarterectomy, angioplasty, stenting, and bypass grafting. Bypass grafting describes a surgical procedure during which a bypass from the ascending aorta to the innominate artery is created. Our case depicts a patient post innominate artery bypass graft with a less commonly encountered postsurgical anatomy.

Author Correction: Influence of soil moisture on codenitrification fluxes from a urea-affected pasture soil.

A correction has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Pipeline Embolization Device for Pericallosal Artery Aneurysms: A Retrospective Single Center Safety and Efficacy Study.

BACKGROUND: Pericallosal artery aneurysm treatment may be challenging using traditional endovascular techniques. OBJECTIVE: To demonstrate the feasibility, efficacy, and safety of endovascular treatment of pericallosal artery aneurysm using flow diverters. METHODS: We performed a retrospective review of our institutional database from July 2013 through July 2016 and identified 7 subjects with a pericallosal artery aneurysm treated with the Pipeline embolization device (ev3 Neurovascular, Medtronic, Dublin, Ireland) and at least 1 follow-up angiogram. Technical feasibility, procedural complication, angiographic results, and clinical outcome were evaluated. RESULTS: Placement of the Pipeline embolization device was successful in all cases without evidence of procedural complication. Five out of 7 subjects showed a complete aneurysm occlusion at 6- to 12-mo follow-up angiogram. The 2 subjects with persistent aneurysm filling showed decreased aneurysm sac volume on follow-up angiograms (96% and 60%). There was no evidence of in-implant stenosis or intimal hyperplasia. No thromboembolic or hemorrhagic complications were seen during the follow-up period. Only 1 patient had a transient change in Modified Rankin scale score from baseline as a result of different unrelated procedure. CONCLUSION: Our preliminary results demonstrate feasibility of the use of flow diverter stent for treatment of aneurysms of the pericallosal artery with rate of aneurysm occlusion comparable to literature and without evidence of increased procedural or short-term morbidity. A long-term and larger cohort study is needed to validate our findings.

Trigeminocardiac reflex caused by selective angiography of the middle meningeal artery.

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

Influence of soil moisture on codenitrification fluxes from a urea-affected pasture soil.

Intensively managed agricultural pastures contribute to N2O and N2 fluxes resulting in detrimental environmental outcomes and poor N use efficiency, respectively. Besides nitrification, nitrifier-denitrification and heterotrophic denitrification, alternative pathways such as codenitrification also contribute to emissions under ruminant urine-affected soil. However, information on codenitrification is sparse. The objectives of this experiment were to assess the effects of soil moisture and soil inorganic-N dynamics on the relative contributions of codenitrification and denitrification (heterotrophic denitrification) to the N2O and N2 fluxes under a simulated ruminant urine event. Repacked soil cores were treated with 15N enriched urea and maintained at near saturation (-1 kPa) or field capacity (-10 kPa). Soil inorganic-N, pH, dissolved organic carbon, N2O and N2 fluxes were measured over 63 days. Fluxes of N2, attributable to codenitrification, were at a maximum when soil nitrite (NO2-) concentrations were elevated. Cumulative codenitrification was higher (P = 0.043) at -1 kPa. However, the ratio of codenitrification to denitrification did not differ significantly with soil moisture, 25.5 ± 15.8 and 12.9 ± 4.8% (stdev) at -1 and -10 kPa, respectively. Elevated soil NO2- concentrations are shown to contribute to codenitrification, particularly at -1 kPa.

Two-year single-center experience with the 'Baby Trevo' stent retriever for mechanical thrombectomy in acute ischemic stroke.

OBJECTIVE: To evaluate the safety and efficacy of the 'Baby Trevo' (Trevo XP ProVue 3×20 mm Retriever) stent retriever for large vessel occlusions (LVOs) in acute ischemic stroke (AIS). MATERIALS AND METHODS: We retrospectively analyzed our stroke database and included all patients treated with the Baby Trevo for distal LVOs in AIS. Patient gender, mean age, vascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score at presentation, and modified Rankin Scale (mRS) score at baseline and 90-day follow-up were documented. Reperfusion rates for the vessels treated were recorded using the Thrombolysis in Cerebral Infarction (TICI) classification. Occurrence of vasospasm and new or evolving infarcts in the treated vascular territory was documented. RESULTS: Thirty-five subjects with a mean NIHSS score of 18 were included. The Baby Trevo device was used in 38 branches of the anterior and posterior circulations. TICI 2b/3 blood flow was restored after one single pass in 20/38 (52.6%) and after two or three passes in 11 vessels. The remaining vessels required either more than three passes, showed less than a TICI 2b/3 reperfusion (n=3), or demonstrated failure to retrieve the clot (n=4). TICI 2b/3 reperfusion was achieved in 30 patients (85.7%). No vessel injuries, rupture, or significant vasospasm were seen. Overall, a mRS score of ≤2 was seen in 56.5% of the subjects successfully treated with the Baby Trevo at 90 days and in 81.3% of surviving patients; seven patients died (20%). CONCLUSIONS: Our preliminary data suggest that the 'Baby Trevo' achieves a high recanalization rate without any significant risk. Larger cohort studies are needed to validate the clinical benefit.

Use of self-expanding stents for better intracranial flow diverter wall apposition.

Background Flow diverter (FD) malapposition is associated with stroke-related complications. We document the use of self-expanding nitinol stents to remove/reduce the ledge of a FD deployed for aneurysm treatment. Methods We identified five patients who were treated with the Pipeline embolization device (PED) in conjunction with a Neuroform EZ stent for inadequate wall apposition of the ends of the FD at our institution between May 2014 and July 2015. Among other parameters, angiographic results, cone-beam computed tomography assessment of wall apposition and patient clinical outcome were evaluated. Results Incomplete device end apposition was seen in three cases, and precarious positioning of the distal end of the PED over the aneurysm neck was seen in two cases. In all five cases, successful treatment with good wall apposition and proper pinning of the PED distal edge was achieved using an additional Neuroform EZ stent. Appropriate aneurysm neck coverage and flow stagnation was seen in all cases. The combination of high radial outward force and open-cell design permits the Neuroform EZ stent to jail the malappositioned edges of the FD while maintaining good vessel-wall apposition itself and prevent migration of the PED. Short-term follow-up angiography showed device patency and complete aneurysm obliteration in all cases. Conclusions Preliminary results of this small case series suggest that the Neuroform EZ stent allows for effective treatment of FD malapposition in selected patients amenable for this endovascular approach. Long-term and larger cohort studies are needed to validate these results.

Use of the Pipeline embolization device for recurrent and residual cerebral aneurysms: a safety and efficacy analysis with short-term follow-up.

OBJECTIVE: Evaluation of the safety and efficacy of the Pipeline embolization device (PED) when used as second-line treatment for recurrent or residual, pretreated ruptured and unruptured intracranial aneurysms (IAs). METHODS: Retrospective review of our database to include all patients who were treated with a PED for recurrent or residual IAs following surgical clipping or coiling. We evaluated neurological outcome and angiograms at discharge, 6- and 12-months' follow-up and assessed intimal hyperplasia at follow-up. RESULTS: Twenty-four patients met our inclusion criteria. Most IAs were located in the anterior circulation (n=21). No change of preprocedure modified Rankin Scale score was seen at discharge or at any scheduled follow-up. Complete or near-complete aneurysm occlusion on 6- and 12-month angiograms was seen in 94.4% (17/18 cases) and 93.3% (14/15 cases), respectively. Complete or near-complete occlusion was seen in 100% of previously ruptured and 85.7% (6/7 cases) and 83.3% (5/6 cases) of previously unruptured cases at the 6- and 12-months' follow-up, respectively. One case of moderate intimal hyperplasia was observed at 6 months and decreased to mild at the 12-months' follow-up. No difference in device performance was observed among pretreated unruptured or ruptured IAs. CONCLUSIONS: Treatment of recurrent or residual IAs with a PED after previous coiling or clipping is feasible and safe. There is no difference in device performance between ruptured or unruptured IAs.

Lobar distribution of lesion volumes in late-life depression: the Biomedical Informatics Research Network (BIRN).

White matter hyperintense lesions on T2-weighted images are associated with late-life depression. Little work has been carried out examining differences in lesion location between elderly individuals with and without depression. In contrast to previous studies examining total brain white matter lesion volume, this study examined lobar differences in white matter lesion volumes derived from brain magnetic resonance imaging. This study examined 49 subjects with a DSM-IV diagnosis of major depression and 50 comparison subjects without depression. All participants were age 60 years or older. White matter lesion volumes were measured in each hemisphere using a semiautomated segmentation process and localized to lobar regions using a lobar atlas created for this sample using the imaging tools provided by the Biomedical Informatics Research Network (BIRN). The lobar lesion volumes were compared against depression status. After controlling for age and hypertension, subjects with depression exhibited significantly greater total white matter lesion volume in both hemispheres and in both frontal lobes than did control subjects. Although a similar trend was observed in the parietal lobes, the difference did not reach a level of statistical significance. Models of the temporal and occipital lobes were not statistically significant. Older individuals with depression have greater white matter disease than healthy controls, predominantly in the frontal lobes. These changes are thought to disrupt neural circuits involved in mood regulation, thus increasing the risk of developing depression.

Trigeminocardiac reflex caused by selective angiography of the middle meningeal artery.

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

Utilization of a New Intracranial Support Catheter as an Intermediate Aspiration Catheter in the Treatment of Acute Ischemic Stroke: Technical Report on Initial Experience.

The endovascular management of acute ischemic stroke (AIS) due to emergency large vessel occlusion (ELVO) has become the standard of care after the recent publication of landmark randomized, controlled trials. Mechanical thrombectomy, in addition to intravenous thrombolysis (within 4.5 hours when eligible), is now part of the algorithm of the standard of care when treating AIS in patients with ELVO in the anterior circulation up to six hours after symptom onset. A newly introduced device, the Arc™ intracranial support catheter (Medtronic, Irvine, USA), is specifically designed for the introduction of neurointerventional devices into the cerebral vasculature and facilitates the delivery of microcatheters into smaller, more distal intracranial vessels. This technical report describes the use of the Arc™ intracranial support catheter in the setting of AIS.

Increases in regional subarachnoid CSF without apparent cortical gray matter deficits in schizophrenia: modulating effects of sex and age.

OBJECTIVE: The authors investigated the modulating effects of biological sex and age on regional decreases in cortical gray matter and increases in subarachnoid CSF in 25 patients with chronic schizophrenia and 28 group-matched healthy comparison subjects. METHOD: Computational cortical pattern-matching methods were employed to measure the local proportions of gray matter and subarachnoid CSF at thousands of homologous cortical surface locations in each subject using high-resolution magnetic resonance images. Principal-component analysis reduced tissue proportion values obtained at each cortical surface point into component scores for each subject. Principal-component analysis scores were used as dependent variables in statistical analyses that included diagnosis, age, and sex as predictor variables. To reveal more regional changes in tissue proportions, statistical differences in gray matter and CSF were compared at each cortical surface location and mapped in three dimensions. RESULTS: Principal-component analyses revealed main effects of diagnosis, sex, and age for the CSF increases seen in the schizophrenia patients, in male subjects, and in association with age. Significant diagnosis-by-age, diagnosis-by-sex, and diagnosis-by-sex-by-age interactions were also observed, revealing CSF increases in male patients at younger ages. Statistical maps showed regional increases in subarachnoid CSF in association with the above effects. For cortical gray matter measurements, only main effects of age were observed. CONCLUSIONS: Regionally specific increases in sulcal and subarachnoid CSF occur during adulthood and appear prematurely in male schizophrenia patients. Cortical gray matter reductions show aging effects but are below the threshold of significance in schizophrenia.

Utility of preoperative functional magnetic resonance imaging for identifying language cortices in patients with vascular malformations.

OBJECT: The goal of this study was to evaluate the utility of preoperative functional magnetic resonance (fMR) imaging in the prediction of whether a given cortical area would be deemed essential for language processing by electrocortical stimulation mapping (ESM). METHODS: The authors studied patients with vascular malformations, specifically arteriovenous malformations (AVMs) and cavernous angiomas, in whom blood-flow patterns are not normal and in whom a perfusion-dependent mapping signal may be questionable. Ten patients were studied (seven harboring AVMs and three with cavernous angiomas). The authors used a battery of linguistic tasks, including visual object naming, word generation, auditory responsive naming, visual responsive naming, and sentence comprehension, to identify brain regions that were consistently activated across expression and comprehension linguistic tasks. In a comparison of ESM and fMR imaging activations, the authors varied the matching criteria (overlapping activations, adjacent activations, and deep activations) and the radii of influence of ESM (2.5, 5, and 10 mm) to determine the effects of these factors on the sensitivity and specificity of fMR imaging. The sensitivity and specificity of fMR imaging were dependent on the task, lobe, and matching criterion. For the population studied, the sensitivity and specificity of fMR imaging activations during expressive linguistic tasks were found to be up to 100 and 66.7%, respectively, in the frontal lobe, and during comprehension linguistic tasks up to 96.2 and 69.8%, respectively, in the temporal and parietal lobes. The sensitivity and specificity of each disease population (patients with AVMs and those with cavernous angiomas) and of individuals were consistent with those values reported for the entire population studied. CONCLUSIONS: The authors conclude that preoperative fMR imaging is a highly sensitive preoperative planning tool for the identification of which cortical areas are essential for language and that this imaging modality may play a future role in presurgical planning for patients with vascular malformations.

Utility of preoperative functional magnetic resonance imaging for identifying language cortices in patients with vascular malformations.

OBJECT: The goal of this study was to evaluate the utility of preoperative functional magnetic resonance (fMR) imaging in the prediction of whether a given cortical area would be deemed essential for language processing by electrocortical stimulation mapping (ESM). METHODS: The authors studied patients with vascular malformations, specifically arteriovenous malformations (AVMs) and cavernous angiomas, in whom blood-flow patterns are not normal and in whom a perfusion-dependent mapping signal may be questionable. Ten patients were studied (seven harboring AVMs and three with cavernous angiomas). The authors used a battery of linguistic tasks, including visual object naming, word generation, auditory responsive naming, visual responsive naming, and sentence comprehension, to identify brain regions that were consistently activated across expression and comprehension linguistic tasks. In a comparison of ESM and fMR imaging activations, the authors varied the matching criteria (overlapping activations, adjacent activations, and deep activations) and the radii of influence of ESM (2.5, 5, and 10 mm) to determine the effects of these factors on the sensitivity and specificity of fMR imaging. The sensitivity and specificity of fMR imaging were dependent on the task, lobe, and matching criterion. For the population studied, the sensitivity and specificity of fMR imaging activations during expressive linguistic tasks were found to be up to 100 and 66.7%, respectively, in the frontal lobe, and during comprehension linguistic tasks up to 96.2 and 69.8%, respectively, in the temporal and parietal lobes. The sensitivity and specificity of each disease population (patients with AVMs and those with cavernous angiomas) and of individuals were consistent with those values reported for the entire population studied. CONCLUSIONS: The authors conclude that preoperative fMR imaging is a highly sensitive preoperative planning tool for the identification of which cortical areas are essential for language and that this imaging modality may play a future role in presurgical planning for patients with vascular malformations.