Seamounts and ridges are often invoked to explain subduction‐related phenomena such as flat slab generation, but the extent of their involvement remains controversial. An analysis of seismicity in ...the region of the Pampean flat slab through an application of an automated catalog generation algorithm resulted in 35,924 well constrained local earthquake hypocenters and a total of 12,172 focal mechanisms. Several new features related to the subduction of the Juan Fernandez Ridge (JFR) were discovered, including (a) a series of parallel lineaments of seismicity in the subducted Nazca plate separated by about 50 km and trending about 20°, and (b) a strong spatial correlation between these deeper (>80 km depth) regions of intense seismicity and concentrations of activity in the crust almost directly above it. Focal mechanisms of the deeper events are almost exclusively (∼81%) normal, while those in the crust are predominantly (∼70%) reverse. The deeper lineaments mirror the orientation and spacing of several seamount chains seen on the Nazca plate, suggesting that these patterns are caused by the same types of features at depth. This would imply that relatively minor features persist as slab anomalies long after they are subducted. The correlation of the deeper seismicity that defines these features with seismicity in the mid to lower crust suggests a genetic relation between the two. We postulate that volatiles from the subducted ridges percolate into the South American crust and induce seismicity essentially by fracking it.
Plain Language Summary
The ocean floor has many anomalous features such as seamounts and ridges that are believed to have profound consequences for subduction zones. Some of these effects can be illuminated by determining the locations and mechanisms of earthquakes associated with them. Seismic data collected near one of these features, the Juan Fernandez Ridge beneath South America, were analyzed with an automated catalog generation routine to significantly increase the number of well‐constrained earthquake locations from this area. Plots of these new locations reveal patterns in and around the subducted ridge that mirror the distribution of minor ridges on the Nazca plate, suggesting that the consumption of similar ridges is responsible for this activity. Moreover, these patterns are reflected in the patterns of earthquakes in the South American crust directly above them, also suggesting a genetic relationship. We hypothesize that volatiles such as water or carbon dioxide are being released by these subducted ridges, migrating through the South American mantle, and essentially fracking the mid to lower crust by increasing pore pressure.
Key Points
Automatically generated catalogs of seismicity in the Pampean flab slab show parallel lineaments of seismicity in the Nazca plate
The lineaments are reflected in the bearing and spacing of seamount chains seen in Nazca plate bathymetry
Correlation of mantle seismicity with that in the crust suggests that subducted ridges release volatiles that induce crustal seismicity
Patients with chronic Chagas cardiomyopathy (CCC) have pronounced myocardial fibrosis, which may predispose to sudden cardiac death, despite well-preserved global left ventricular (LV) systolic ...function. Cardiac magnetic resonance can assess myocardial fibrosis by late gadolinium enhancement (LGE) sequences.
This prospective study evaluated if the presence of scar by LGE predicted hard adverse outcomes in a cohort of patients with CCC.
A prospective cohort of 140 patients with CCC (52.1% female; median age 57 years interquartile range: 45 to 67 years) were included. Cardiac magnetic resonance cine and LGE imaging were performed at enrollment with a 1.5-T scanner. The primary endpoint was the combination of cardiovascular death and sustained ventricular tachycardia. The secondary endpoint was the combination of cardiovascular death, sustained ventricular tachycardia, or cardiovascular hospitalization during follow-up.
After a median of 34 months (interquartile range: 24 to 49 months) of follow-up, 11 cardiovascular deaths, 3 episodes of sustained ventricular tachycardia, and 20 cardiovascular hospitalizations were recorded. LGE scar was present in 71.4% of the patients, with the lateral, inferolateral, and inferior walls most commonly affected. Patients with positive LGE had lower LV ejection fraction and higher LV end-diastolic volume and LV mass than patients without LGE. No difference in other cardiovascular risk factors was noted. Patients with scar had higher event rates compared with those without scar for the primary (p = 0.043) and the secondary (p = 0.016) endpoint. In multivariable analysis, age and LGE area were related to primary outcome; age and lower LV ejection fraction were related to the secondary outcome. The pattern of LGE myocardial fibrosis was transmural, focal, or diffuse scar in approximately one-third of patients with positive LGE, and no pattern was specifically related to outcomes.
In patients with CCC, presence of scar by LGE is common and is strongly associated with major adverse outcomes.
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Purpose: To clarify interferon-gamma release assay (IGRA) contributions to intraocular tuberculosis management, according to related TB endemic prevalence.
Methods: Despite extensive investigations, ...including IGRA, the diagnosis of intraocular tuberculosis (TB) is still challenging and remains mostly presumptive. According to the literature, it appears that management of suspected ocular TB differs significantly based on whether patients are from areas of high TB prevalence or from non-TB-endemic countries. The accuracy and final contribution of chest X-rays, tuberculin skin test and IGRA differ significantly according to low or high endemic TB areas. This work aims to review IGRA test outcomes in the light of these clinical and epidemiological settings. We therefore focused our analysis and its subsequent guidelines proposal based on the TB prevalence where the patient lives.
Conclusion: We believe that distinct guidelines should be determined for managing patients with suspected ocular TB, first taking into consideration the relative TB prevalence.
The process of external academic accreditation involves quality control and auditing measures that focus on the design, delivery, and outcomes of education. It is a demanding and disruptive process ...in terms of effort, time, money, and human resources. Nevertheless, the extent to which external quality assurance and accreditation procedures affect students’ performance at the end of the learning cycle has not been well studied thus far.
A retrospective quantitative secondary data analysis was conducted in The King Saud University (KSU) undergraduate medical program, with a before–after comparison research design to assess the impact of external accreditation on students’ mean grade scores during an accreditation cycle.
Overall, the data pertaining to 1090 students who attended 32,677 examination encounters were included in the analysis. The pre- and post-accreditation analysis revealed a statistically significant improvement in the students' mean scores—80 ± 9 (pre) versus 87 ± 11 (post), with a p-value of (p = 0.003) and a Cohen's d value of 0.591. On the other hand, there was no statistically significant difference in the students' mean passing percentages—96 ± 5 (pre) versus 96 ± 9 (post), with a p-value of (p = 0.815) and a Cohen's d value of 0.043.
The actions involved in the planning phase and the journey through the self-study evaluation not only verify the program's competencies but also functioned as critical boosters for quality improvement processes and, hence, students' learning experiences.
Abstract Biotherapies used in clinical practice for the treatment of ophthalmologic manifestations of systemic diseases include interferons (IFN), intravenous immunoglobulins (IVIG) and monoclonal ...antibodies (anti-TNF, anakinra, tocilizumab and rituximab). Several open prospective studies have shown the effectiveness of IFN-α (78 to 98% complete remission) for the treatment of severe uveitis in Behcet's disease. IFN is capable of inducing prolonged remission and continued after his arrest, in 20–40% of patients. Side effects (flu-like, psychological effects) limit its use in practice. Anti-TNFα (infliximab and adalimumab) represents an attractive alternative therapeutic in severe uveitis refractory to immunosuppressants, especially in Behcet's disease. They are almost always (> 90% of cases) and rapidly effective but their action is often suspensive. Anti-TNFα requires an extended prescription or takes over from another immunosuppressant once ocular inflammation has been controlled. IVIG are used for the treatment of Kawasaki disease and Birdshot disease. Several open or retrospective studies showed their effectiveness for the treatment of severe and refractory cicatricial pemphigoid. Tolerance of IVIG is good but their efficacy is transient. Rituximab showed an efficacy in few observations of various inflammatory eye diseases (uveitis, scleritis and idiopathic inflammatory pseudo-tumors or associated with granulomatosis with polyangiitis) and cicatricial pemphigoid. The risk of infection associated with this biotherapy limits its use in refractory diseases to conventional therapy. Anakinra (a soluble antagonist of IL-1R) showed interesting results in terms of efficiency in one small open study in Behcet's disease. Its safety profile is good and with a quick action that could be interesting for the treatment of severe uveitis.
Ocular drug side effects are very varied and can affect all the structures of the eye. The purpose of this review is to help clinicians: (i) to evoke this drug-induced toxicity yearly in the course ...of an unexplained ocular injury, before its damage become irreversible, (ii) to be able to recognize induced paradoxical ocular inflammation, mimicking an inflammatory pathology flare-up, especially in patient under anti-TNF regimen and (iii) to propose a more in-depth knowledge on recently described ocular toxicities from targeted cancer therapy, mainly the tyrosine kinase inhibitors.
Ocular tuberculosis (TB) diagnosisremains difficult and quantiferon (QFT) contribution needs still yet to be specified, despite its generalization in France. The purpose of this observational study ...is to assess in which ocular inflammation (OI) presentation QFT is prescribed and to evaluate the added value of new QuantiFERON®-TB Gold Plus (QFT-Plus) test for diagnosis ocular TB diagnosis.
Monocentric, observational study, carried out in an ophthalmology department over a period of 5 months. Inclusion criteria were defined as an existence of an OI for which a QFT-Plus test was part of the etiological investigations. Of the 316 consecutive files, 72 were excluded (indeterminate test, prescription before anti-TNFα or immunosuppressant initiation, missing data, wrong indication) and 244 were selected and divided into two groups: group one (anterior uveitis/episcleritis, n=129) and group two (intermediate/posterior uveitis/optic neuritis/ocular myositis, n=115). All positive QFT patients underwent an etiological investigation including thoracic imaging.
Forty-five patients, aged 52±12 years, had positive QFT (18.5%), including 18 patients for group 1 and 27 for group 2. Living in TB-endemic area, TB exposure and chest imaging abnormalities were identified in 70%, 27% and 22% of cases, respectively. OI was chronic in 36% of cases (group one, 4/18; group two, 12/27). None of the 18 patients, in group 1, received anti-tuberculosis treatment (ATT) or experienced a relapse during one-year follow-up. Four QFT+ patients, from group 2 (15%) had another associated disease explaining their uveitis. Among the 23 other patients without identified etiology, 13 had at least one relevant ophthalmological signs predictive of TB uveitis (posterior synechiae, retinal vasculitis and/or choroidal granuloma) (59%). Eleven patients received a 6-month ATT trial. Radiological abnormalities and granulomas at angiography were significantly more frequent among treated patients (p=0.03 and 0.001, respectively). A full OI recovery was observed for 8 patients (73%), considered ex-post as ocular TB. Nine patients in group 2 received rifampicin/isoniazid dual therapy for 3 months, but no conclusion could be drawn as to the benefit of such prescription on OI. QFT rate comparison, according to CD4 stimulation by ESAT-6/CFP-10 peptides or by CD4/CD8 co-stimulation, was comparable and found only 4 cases of discrepancy (1.6%). None of these 4 cases had ocular TB diagnosis.
Positive QFT frequency among patients consulting for posterior OI remains high. In this study, radiological abnormalities and granulomas at angiography seemed to be more closely related to clinician decision for starting ATT trial in QFT+ patients, which was effective in 73% of cases. QFT-Plus does not seem more relevant than QFT-TB in exploring an OI. Prospective studies are necessary to codify QFT management in the etiological assessment of OI and clearly define ATT trial indications as well as their modalities.
Although tuberculous meningitis is an uncommon presentation of tuberculosis, it still remains one of the deadliest forms of this disease. In this context, the occurrence of a cerebral infarct is an ...aggravating factor.
A 48-year-old Asian man presented himself in the emergency room for dysarthria and dysphagia of progressive onset. Cerebral CT showed a recent ischemic defect of the right internal capsule. Lumbar puncture showed meningitis with low sugar levels. Pulmonary micronodules on the thoracic CT suggested tuberculosis, which was confirmed by a broncho-alveolar lavage. Anti-tuberculosis treatment and early corticosteroid resulted in an improvement of the patient's state.
Cerebral infarctions in patients with tuberculous meningitis are events that cannot be underestimated in terms of frequency or severity. Their poor prognosis is partly the result of insufficiently defined management, which combines anti-tuberculosis treatment and early corticosteroid therapy.
Background This study was undertaken to validate previously reported safety and symptomatic outcomes of transoral incisionless fundoplication (TIF), evaluate the relative benefit of TIF within ...different gastroesophageal reflux disease (GERD) subgroups, and to determine predictors of success in community settings. Study Design Between January 2010 and February 2011, 100 consecutive patients who underwent TIF procedures at 10 centers were enrolled in this prospective, open-label, multicenter, single-arm study. Symptom improvement and objective outcomes of TIF were analyzed at 6-month follow-up. Results One hundred TIF procedures were performed. No complications were reported. Median GERD symptom duration was 9 years (range 1 to 35 years) and median duration of proton pump inhibitor (PPI) use was 7 years (1 to 20 years). Maximal medical therapy resulted in incomplete symptom control for 92% of patients; GERD Health-Related Quality of Life (GERD-HRQL) total score was normalized in 73%. Median heartburn and regurgitation scores improved significantly, from 18 (range 0 to 30) and 15 (range 0 to 30) on PPIs before TIF to 3 (range 0 to 25) and 0 (range 0 to 25), respectively; p < 0.001. Median Reflux Symptom Index scores were reduced after TIF from 24 (range 14 to 41) to 7 (range 0 to 44); p < 0.001. Eighty percent of patients were completely off PPIs after TIF vs 92% of patients on PPIs before TIF. Preoperative factors associated with clinical outcomes were less severe heartburn (total GERD-HRQL ≤ 30, p = 0.02) and the presence of esophagitis (p < 0.02). Conclusions Transoral incisionless fundoplication is safe and effective in multiple community-based settings in the treatment of medically refractory GERD, as demonstrated by an absence of complications, excellent symptom relief, and complete cessation of PPIs at 6-month follow-up.
Patient: Male, 33-year-old
Final Diagnosis: Traumatic Brown-Séquard syndrome
Symptoms: Bilateral lower limb weakness • contralateral (right) hypoesthesia from the level of the nipple below • knee and ...ankle jerks both were 2 on the right side and 0 on the left
Medication: —
Clinical Procedure: Magnetic resonance imaging (MRI) of the cervical and thoracic spine • whole-body computed tomography (CT)
Specialty: Surgery
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