Lake-level rise in the late Pleistocene and active subaquatic volcanism since the Holocene in Lake Kivu; East African Rift

The history of Lake Kivu is strongly linked to the activity of the Virunga volcanoes. Subaerial and subaquatic volcanoes, in addition to lake-level changes, shape the subaquatic morphologic and structural features in Lake Kivu's Main Basin. Previous studies revealed that volcanic eruptions blocked the former outlet of the lake to the north in the late Pleistocene, leading to a substantial rise in the lake level and subsequently the present- day thermohaline stratification. Additional studies have speculated that volcanic and seismic activities threaten to trigger a catastrophic release of the large amount of gases dissolved in the lake. The current study presents a bathymetric mapping and seismic profiling survey that covers the volcanically active area of the Main Basin at a resolution that is unprecedented for Lake Kivu. New geomorphologic features identified on the lake floor can accurately describe related lake-floor processes for the first time. The late Pleistocene lowstand is observed at 425 m depth, and volcanic cones, tuff rings, and lava flows observed above this level indicate both subaerial and subaquatic volcanic activities during the Holocene. The geomorphologic analysis yields new implications on the geologic processes that have shaped Lake Kivu's basin, and the presence of young volcanic features can be linked to the possibility of a lake overturn.

Risk stratification of normotensive patients with acute symptomatic pulmonary embolism

Treatment guidelines recommend strong consideration of thrombolysis in patients with acute symptomatic pulmonary embolism (PE) that present with arterial hypotension or shock because of the high risk of death in this setting. For haemodynamically stable patients with PE, the categorization of risk for subgroups may assist with decision-making regarding PE therapy. Clinical models [e.g. Pulmonary Embolism Severity Index (PESI)] may accurately identify those at low risk of overall death in the first 3 months after the diagnosis of PE, and such patients might benefit from an abbreviated hospital stay or outpatient therapy. Though some evidence suggests that a subset of high-risk normotensive patients with PE may have a reasonable risk to benefit ratio for thrombolytic therapy, single markers of right ventricular dysfunction (e.g. echocardiography, spiral computed tomography, or brain natriuretic peptide testing) and myocardial injury (e.g. cardiac troponin T or I testing) have an insufficient positive predictive value for PE-specific mortality to drive decision-making toward such therapy. Recommendations for outpatient treatment or thrombolytic therapy for patients with PE necessitate further development of prognostic models and conduct of clinical trials that assess various treatment strategies.

A strategy combining imaging and laboratory biomarkers in comparison with a simplified clinical score for risk stratification of patients with acute pulmonary embolism

This study aimed to assess the performance of two prognostic models-the European Society of Cardiology (ESC) model and the simplified Pulmonary Embolism Severity Index (sPESI)-in predicting short-term mortality in patients with pulmonary embolism (PE).

Copeptin and risk stratification in patients with ischemic stroke and transient ischemic attack: The CoRisk Study

RATIONALE: Copeptin independently predicts functional outcome and mortality at 90 days and one-year after ischemic stroke. In patients with transient ischemic attack, elevated copeptin values indicate an increased risk of further cerebrovascular events. AIMS: The Copeptin Risk Stratification (CoRisk) study aims to validate the predictive value of copeptin in patients with ischemic stroke and transient ischemic attack. In patients with ischemic stroke, the CoRisk study aims to further explore the effect of treatment (i.e. thrombolysis) on the predictive value of copeptin. DESIGN: Prospective observational multicenter study analyzing three groups of patients, i.e. patients with ischemic stroke treated with and without thrombolysis and patients with transient ischemic attack. OUTCOMES: Primary end-point: In patients with ischemic stroke, the primary end-point includes disability (modified Rankin scale from 3 to 5) and mortality (modified Rankin scale 6) at three-months after stroke. In patients with transient ischemic attack, the primary end-point is a recurrent ischemic cerebrovascular event (i.e. ischemic stroke or recurrent transient ischemic attack). Secondary end-point: In patients with ischemic stroke, the secondary end-points include in-house complications (i.e. symptomatic intracerebral hemorrhage, malignant edema, aspiration pneumonia or seizures during hospitalization, and in-house mortality).

The SURTAVI model: proposal for a pragmatic risk stratification for patients with severe aortic stenosis

Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to surgical aortic valve replacement (SAVR) for patients with symptomatic severe aortic stenosis (AS) and a high operative risk. Risk stratification plays a decisive role in the optimal selection of therapeutic strategies for AS patients. The accuracy of contemporary surgical risk algorithms for AS patients has spurred considerable debate especially in the higher risk patient population. Future trials will explore TAVI in patients at intermediate operative risk. During the design of the SURgical replacement and Transcatheter Aortic Valve Implantation (SURTAVI) trial, a novel concept of risk stratification was proposed based upon age in combination with a fixed number of predefined risk factors, which are relatively prevalent, easy to capture and with a reasonable impact on operative mortality. Retrospective application of this algorithm to a contemporary academic practice dealing with clinically significant AS patients allocates about one-fourth of these patients as being at intermediate operative risk. Further testing is required for validation of this new paradigm in risk stratification. Finally, the Heart Team, consisting of at least an interventional cardiologist and cardiothoracic surgeon, should have the decisive role in determining whether a patient could be treated with TAVI or SAVR.

Stratification and Prognostic Relevance of Jass's Molecular Classification of Colorectal Cancer

Background: The current proposed model of colorectal tumorigenesis is based primarily on CpG island methylator phenotype (CIMP), microsatellite instability (MSI), KRAS, BRAF, and methylation status of 0-6-Methylguanine DNA Methyltransferase (MGMT) and classifies tumors into five subgroups. The aim of this study is to validate this molecular classification and test its prognostic relevance. Methods: Three hundred two patients were included in this study. Molecular analysis was performed for five CIMP-related promoters (CRABP1, MLH1, p16INK4a, CACNA1G, NEUROG1), MGMT, MSI, KRAS, and BRAF. Methylation in at least 4 promoters or in one to three promoters was considered CIMP-high and CIMP-low (CIMP-H/L), respectively. Results: CIMP-H, CIMP-L, and CIMP-negative were found in 7.1, 43, and 49.9% cases, respectively. One hundred twenty-three tumors (41%) could not be classified into any one of the proposed molecular subgroups, including 107 CIMP-L, 14 CIMP-H, and two CIMP-negative cases. The 10 year survival rate for CIMP-high patients [22.6% (95%CI: 7-43)] was significantly lower than for CIMP-L or CIMP-negative (p = 0.0295). Only the combined analysis of BRAF and CIMP (negative versus L/H) led to distinct prognostic subgroups. Conclusion: Although CIMP status has an effect on outcome, our results underline the need for standardized definitions of low- and high-level CIMP, which clearly hinders an effective prognostic and molecular classification of colorectal cancer.

Combined anatomical and clinical factors for the long-term risk stratification of patients undergoing percutaneous coronary intervention: the Logistic Clinical SYNTAX score

The SYNTAX score (SXscore), an anatomical-based scoring tool reflecting the complexity of coronary anatomy, has established itself as an important long-term prognostic factor in patients undergoing percutaneous coronary intervention (PCI). The incorporation of clinical factors may further augment the utility of the SXscore to longer-term risk stratify the individual patient for clinical outcomes.

Stratification of cumulative antibiograms in hospitals for hospital unit, specimen type, isolate sequence and duration of hospital stay

BACKGROUND: Empirical antibiotic therapy is based on patients' characteristics and antimicrobial susceptibility data. Hospital-wide cumulative antibiograms may not sufficiently support informed decision-making for optimal treatment of hospitalized patients. METHODS: We studied different approaches to analysing antimicrobial susceptibility rates (SRs) of all diagnostic bacterial isolates collected from patients hospitalized between July 2005 and June 2007 at the University Hospital in Zurich, Switzerland. We compared stratification for unit-specific, specimen type-specific (blood, urinary, respiratory versus all specimens) and isolate sequence-specific (first, follow-up versus all isolates) data with hospital-wide cumulative antibiograms, and studied changes of mean SR during the course of hospitalization. RESULTS: A total of 16 281 isolates (7965 first, 1201 follow-up and 7115 repeat isolates) were tested. We found relevant differences in SRs across different hospital departments. Mean SRs of Escherichia coli to ciprofloxacin ranged between 64.5% and 95.1% in various departments, and mean SRs of Pseudomonas aeruginosa to imipenem and meropenem ranged from 54.2% to 100% and 80.4% to 100%, respectively. Compared with hospital cumulative antibiograms, lower SRs were observed in intensive care unit specimens, follow-up isolates and isolates causing nosocomial infections (except for Staphylococcus aureus). Decreasing SRs were observed in first isolates of coagulase-negative staphylococci with increasing interval between hospital admission and specimen collection. Isolates from different anatomical sites showed variations in SRs. CONCLUSIONS: We recommend the reporting of unit-specific rather than hospital-wide cumulative antibiograms. Decreasing antimicrobial susceptibility during hospitalization and variations in SRs in isolates from different anatomical sites should be taken into account when selecting empirical antibiotic treatment.

[Pediatric cardiac disease: indications for family screening and risk stratification]

In some forms of cardiac disease in childhood, familial occurrence is frequent. This implies the question whether family members should undergo cardiologic screening examinations. For cardiomyopathies the familiarity is so frequent and morbidity so important that examination by echo of all first degree relatives is recommended. As these cardiomyopathies may develop its phenotype all along a lifetime, repetitive examinations usually are indicated. For the primary electrical diseases the so called channelopathies the same is true, as for the high rate of familial occurrence and the high morbidity. Thus ECG screening of first degree relatives is recommended. In a child with congenital heart disease there are no recommendations with regard to familial screening and cardiological examinations usually are indicated only in case of clinical suspicion for heart disease.

Prospective risk stratification of sudden cardiac death in Marfan's syndrome.

BACKGROUND Marfan syndrome (MFS) is a variable, autosomal-dominant disorder of the connective tissue. In MFS serious ventricular arrhythmias and sudden cardiac death (SCD) can occur. The aim of this prospective study was to reveal underlying risk factors and to prospectively investigate the association between MFS and SCD in a long-term follow-up. METHODS 77 patients with MFS were included. At baseline serum N-terminal pro-brain natriuretic peptide (NT-proBNP), transthoracic echocardiogram, 12-lead resting ECG, signal-averaged ECG (SAECG) and a 24-h Holter ECG with time- and frequency domain analyses were performed. The primary composite endpoint was defined as SCD, ventricular tachycardia (VT), ventricular fibrillation (VF) or arrhythmogenic syncope. RESULTS The median follow-up (FU) time was 868 days. Among all risk stratification parameters, NT-proBNP remained the exclusive predictor (hazard ratio [HR]: 2.34, 95% confidence interval [CI]: 1.1 to 4.62, p=0.01) for the composite endpoint. With an optimal cut-off point at 214.3 pg/ml NT-proBNP predicted the composite primary endpoint accurately (AUC 0.936, p=0.00046, sensitivity 100%, specificity 79.0%). During FU, seven patients of Group 2 (NT-proBNP ≥ 214.3 pg/ml) reached the composite endpoint and 2 of these patients died due to SCD. In five patients, sustained VT was documented. All patients with a NT-proBNP<214.3 pg/ml (Group 1) experienced no events. Group 2 patients had a significantly higher risk of experiencing the composite endpoint (logrank-test, p<0.001). CONCLUSIONS In contrast to non-invasive electrocardiographic parameter, NT-proBNP independently predicts adverse arrhythmogenic events in patients with MFS.

Stratification and compartmentalisation of immunoglobulin responses to commensal intestinal microbes

The gastrointestinal tract is heavily colonized with commensal microbes with the concentration of bacteria increasing longitudinally down the length of the intestine. Bacteria are also spatially distributed transversely from the epithelial surface to the intestinal lumen with the inner mucus layer normally void of bacteria. Maintenance of this equilibrium is extremely important for human health and, as the dominant immunoglobulin at mucosal sites, IgA influences mutualism between the host and its normal microbiota. In this review we focus on the links between immune and microbial geography of the mammalian intestinal tract.