Morphological variations of the vermiform appendix in Iranian cadavers: a study from developing countries

Background: The vermiform appendix is a worm-like tube containing a large amount of lymphoid follicles. In our knowledge, there is a little standard data about the vermiform appendix in Iranian population. Therefore, the objective of this study was to investigate the normal appendix size in Iranian cadavers. Materials and methods: A cross-sectional study was undertaken between June 2014 and July 2015, in the autopsy laboratory, Legal Medicine Organisation, Razavi Khorasan province, Iran. A total of 693 cadavers with the mean age of 40.46 ± 20.99 years were divided into 10 groups. After writing down position of the appendix, the length, diameter and weight of the appendix were measured. Statistical analysis was performed using SPSS software. Results: The mean values of the demographic characteristics included — age: 40.46 ± 20.99 years; weight: 63.47 ± 17.84 kg; height: 159.95 ± 28.23 cm. The mean values of the appendix length, diameter, weight and index in the cadavers were 8.52 ± 2.99 cm, 12.17 ± 4.53 mm, 6.43 ± 3.26 g and 0.013 ± 0.01, respectively. The most common position of the appendix was retrocaecal in 71.7% of cases. Significant correlations were evident between the value of demographic data and appendix size (p < 0.05). The diameter (p = 0.002) and index of the appendix (p = 0.003) showed significant difference between males and females. Conclusions: Having standard data on the vermiform appendix is useful for clinicians as well as anthropologists. The findings of the present study can provide information about morphologic variations of the appendix in Iranian population.  

Left Atrial scar assessment using imaging with isotropic spatial resolution and compressed sensing

Summary. We assess left atrial scar using late gadolinium enhancement (LGE) with isotropic spatial resolution of $1.4^3 mm^3$ by using highly accelerated LOST [1] reconstruction. Background. Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia [2]. Pulmonary vein isolation (PVI) using radiofrequency (RF)-ablation is the leading treatment for AF. Recently, LGE imaging of the LA has been used to identify atrial wall scar due to RF-ablation [3]. However, current LGE methods have limited spatial resolution that substantially impact assessment of scar in the complex geometry of PVs and LA. In this study, we sought to utilize prospective random k-space sampling and LOST [1] for accelerated LGE imaging, where reduction in imaging time was traded-off for improved isotropic spatial-resolution. Methods. 23 patients with history of AF (6 females, $58.1 \pm 9.6$ years, 9 pre-PVI, 2 with history of PVI; 8 post-PVI; 3 with both pre and post-PVI) were recruited for this study. LGE images were acquired 10-to-20 minutes after bolus infusion of 0.2 mmol/kg Gd-DTPA. Free-breathing ECG-triggered navigator-gated inversion-recovery GRE sequences were used for all acquisitions ($TR/TE/ \alpha = 5.2/2.6ms/25°, FOV=320×320×100mm$). The PV inflow artifact reduction technique in [4] was also utilized. For each patient, a standard non-isotropic 3D LGE scan ($1.4×1.4×4.0mm^3$) and a 3-fold-accelerated highresolution 3D LGE scan ($1.4^3 mm^3$) were performed, with randomized acquisition order. For random undersampling, central k-space (45×35 in ky-kz) was fullysampled, edges randomly discarded, and phase reordering performed as in [5]. Acquisition times were ~4 mins assuming 100% scan-efficiency at 70bpm for both scans. All undersampled data were reconstructed offline using LOST [1]. LOST-reconstructed high-resolution, and standard LGE images were scored by two blinded readers for diagnostic value, presence of LGE(yes/no); and image quality in axial(Ax), coronal(Co) and sagittal (Sa) views (1=poor,4=excellent). Results. Three cases were declared non-diagnostic due to contrast-washout and imperfect inversion-time. LGE was visually present in 14 of the remaining 20 patients based on standard-LGE images, and 12 based on LOST-reconstructed ones (disagreement on one pre- and one postPVI patient). Figure 1 and 2 show comparisons of isotropic vs. non-isotropic LGE images in two patients. Image scores for LOST-LGE: $Ax=2.90 \pm 0.70, Sa=3.33 \pm 0.66, Co=3.00 \pm 0.63$; and standard LGE: $Ax=3.76 \pm 0.54, Sa=2.48 \pm 0.60, Co=2.24 \pm 0.44$, where differences were significant in all views. Conclusions. LOST allows isotropic spatial-resolution in LGE for assessment of LA and PV scar. Isotropic resolution allows reformatting LGE images in any orientation and facilitates assessment of scar. Further clinical study is needed to assess if the improved spatial resolution will impact the diagnostic interpretation of data

Untargeted mass spectrometry lipidomics identifies correlation between serum sphingomyelins and plasma cholesterol

Background Lipoproteins are major players in the development and progression of atherosclerotic plaques leading to coronary stenosis and myocardial infarction. Epidemiological, genetic and experimental observations have implicated the association of sphingolipids and intermediates of sphingolipid synthesis in atherosclerosis. We aimed to investigate relationships between quantitative changes in serum sphingolipids, the regulation of the metabolism of lipoproteins (LDL, HDL), and endophenotypes of coronary artery disease (CAD). Methods We carried out untargeted liquid chromatography – mass spectrometry (UPLC-MS) lipidomics of serum samples of subjects belonging to a cross-sectional study and recruited on the basis of absence or presence of angiographically-defined CAD, and extensively characterized for clinical and biochemical phenotypes. Results Among the 2998 spectral features detected in the serum samples, 1328 metabolic features were significantly correlated with at least one of the clinical or biochemical phenotypes measured in the cohort. We found evidence of significant associations between 34 metabolite signals, corresponding to a set of sphingomyelins, and serum HDL cholesterol. Many of these metabolite associations were also observed with serum LDL and total cholesterol levels but not as much with serum triglycerides. Conclusion Among patients with CAD, sphingolipids in the form of sphingomyelins are directly correlated with serum levels of lipoproteins and total cholesterol. Results from this study support the fundamental role of sphingolipids in modulating lipid serum levels, highlighting the importance to identify novel targets in the sphingolipid metabolic pathway for anti-atherogenic therapies

Dominant gut Prevotella copri in gastrectomised non-obese diabetic Goto-Kakizaki rats improves glucose homeostasis through enhanced FXR signalling

Aims/hypothesis Drug and surgical-based therapies in type 2 diabetes are associated with altered gut microbiota architecture. Here we investigated the role of the gut microbiome in improved glucose homeostasis following bariatric surgery. Methods We carried out gut microbiome analyses in gastrectomised (by vertical sleeve gastrectomy [VSG]) rats of the Goto–Kakizaki (GK) non-obese model of spontaneously occurring type 2 diabetes, followed by physiological studies in the GK rat. Results VSG in the GK rat led to permanent improvement of glucose tolerance associated with minor changes in the gut microbiome, mostly characterised by significant enrichment of caecal Prevotella copri. Gut microbiota enrichment with P. copri in GK rats through permissive antibiotic treatment, inoculation of gut microbiota isolated from gastrectomised GK rats, and direct inoculation of P. copri, resulted in significant improvement of glucose tolerance, independent of changes in body weight. Plasma bile acids were increased in GK rats following inoculation with P. copri and P. copri-enriched microbiota from VSG-treated rats; the inoculated GK rats then showed increased liver glycogen and upregulated expression of Fxr (also known as Nr1h4), Srebf1c, Chrebp (also known as Mlxipl) and Il10 and downregulated expression of Cyp7a1. Conclusions Our data underline the impact of intestinal P. copri on improved glucose homeostasis through enhanced bile acid metabolism and farnesoid X receptor (FXR) signalling, which may represent a promising opportunity for novel type 2 diabetes therapeutics

Synchronization in periodically driven and coupled stochastic systems-A discrete state approach

Wir untersuchen das Verhalten von stochastischen bistabilen und erregbaren Systemen auf der Basis einer Modellierung mit diskreten Zuständen. In Ergänzung zum bekannten Markovschen Zwei-Zustandsmodell bistabiler stochastischer Dynamik stellen wir ein nicht Markovsches Drei-Zustandsmodell für erregbare Systeme vor. Seine relative Einfachheit, verglichen mit stochastischen Modellen erregbarer Dynamik mit kontinuierlichem Phasenraum, ermöglicht eine teilweise analytische Auswertung in verschiedenen Zusammenhängen. Zunächst untersuchen wir den gemeinsamen Einfluß eines periodischen Treibens und Rauschens. Dieser wird entweder mit Hilfe spektraler Größen oder durch Synchronisation des Systems mit dem treibenden Signal charakterisiert. Wir leiten analytische Ausdrücke für die spektrale Leistungsverstärkung und das Signal-zu-Rauschen Verhältnis für periodisch getriebene Renewal-Prozesse her und wenden diese auf das diskrete Modell für erregbare Dynamik an. Stochastische Synchronization des Systems mit dem treibenden Signal wird auf der Basis der Diffusionseigenschaften der Übergangsereignisse zwischen den diskreten Zuständen untersucht. Wir leiten allgemeine Formeln her, um die mittlere Häufigkeit dieser Ereignisse sowie deren effektiven Diffusionskoeffizienten zu berechnen. Über die konkrete Anwendung auf die untersuchten diskreten Modelle hinaus stellen diese Ergebnisse ein neues Werkzeug für die Untersuchung periodischer Renewal-Prozesse dar. Schließlich betrachten wir noch das Verhalten global gekoppelter bistabiler und erregbarer Systeme. Im Gegensatz zu bistabilen System können erregbare Systeme synchronisiert werden und zeigen kohärente Oszillationen. Alle Untersuchungen des nicht Markovschen Drei-Zustandsmodells werden mit dem prototypischen Modell für erregbare Dynamik, dem FitzHugh-Nagumo System, verglichen und zeigen eine gute Übereinstimmung.We investigate the behavior of stochastic bistable and excitable dynamics based on a discrete state modeling. In addition to the well known Markovian two state model for bistable dynamics we introduce a non Markovian three state model for excitable systems. Its relative simplicity compared to stochastic models of excitable dynamics with continuous phase space allows to obtain analytical results in different contexts. First, we study the joint influence of periodic signals and noise, both based on a characterization in terms of spectral quantities and in terms of synchronization with the periodic driving. We present expressions for the spectral power amplification and signal to noise ratio for renewal processes driven by periodic signals and apply these results to the discrete model for excitable systems. Stochastic synchronization of the system to the driving signal is investigated based on diffusion properties of the transition events between the discrete states. We derive general results for the mean frequency and effective diffusion coefficient which, beyond the application to the discrete models considered in this work, provide a new tool in the study of periodically driven renewal processes. Finally the behavior of globally coupled excitable and bistable units is investigated based on the discrete state description. In contrast to the bistable systems, the excitable system exhibits synchronization and thus coherent oscillations. All investigations of the non Markovian three state model are compared with the prototypical continuous model for excitable dynamics, the FitzHugh-Nagumo system, revealing a good agreement between both models

Variabilité de l'érosion hydrique dans le bassin du Hodna: cas du sous-bassin versant de l'oued elham

Le bassin versant du Hodna d’une superficie de 26 000 km² est le cinquième grand bassin de l’Algérie, Il est situé à 150 km à vol d’oiseau au sud de la côte méditerranéenne (Golf de Bejaïa). La situation du bassin du Hodna entre deux séries de montagnes au nord et au sud, organise le bassin autour d’une cuvette fermée presque plate à 400 m d’altitude dite Chott El Hodna (1 150 km²). Cette cuvette reçoit les apports liquides et solides des 17 oueds du Hodna dont l’Oued El ham est le plus grand drainant un sous bassin d’une superficie de 5604 km². Le climat de ce dernier est typiquement semi-aride, caractérisé par des précipitations irrégulières et agressives. Sa précipitation moyenne annuelle est de l’ordre de 185 mm associée à une forte variabilité (coefficient de variation interannuelle Cv = 40% pendant 38 années hydrologiques 1968-2006). Les apports liquides et solides de l’oued El ham sont mesurés par une station hydrométrique (appelée Rocad Sud) placée à l’exutoire du bassin. Dans cette étude, nous utilisons 1293 enregistrements instantanés de débits liquides et concentrations des sédiments en suspension, ce nombre de données couvre une période de 20 années hydrologiques 1968-1989. Oued El ham, transporte annuellement en moyenne 94 Millions de m3 d’eau (avec CV =1.2) et 2.97 millions de tonnes de sédiments (avec Cv =1.0), soit une charge spécifique des sédiments de l’ordre de 530 T/km²/an. La comparaison des résultats obtenus à d’autres bassins algériens montre que l’érosion hydrique dans ce bassin est parmi les plus importantes en Algérie, avec une variabilité interannuelle de l’ordre de 100%. Les apports de l’oued El ham sont déversés dans le chott Hodna (1150 km²), durant la période de cette étude de 21 ans, l’apport solide de l’oued El ham a contribué à l’élévation de la cote terrain du chott de 20 cm en moyenne. Ce qui menace les villages situés dans cette zone (Chelal, Baneou, Maarif…). L’analyse des données à l’échelle saisonnière montre que la plus grande partie de l’érosion hydrique (soit 31.72%) est observée en automne. A l’échelle mensuelle la variabilité est de l’ordre de 80%, durant la période de l’étude plus de la moitié du transport solide est observée en trois mois septembre (18.40%), avril (17.81%) et juin (18.82%). En fait, les crues de début d’automne et de fin de printemps sont responsables de la grande partie de l’érosion

Variabilité de l'érosion hydrique dans le bassin du Hodna: cas du sous-bassin versant de l'oued elham

Le bassin versant du Hodna d’une superficie de 26 000 km² est le cinquième grand bassin de l’Algérie, Il est situé à 150 km à vol d’oiseau au sud de la côte méditerranéenne (Golf de Bejaïa). La situation du bassin du Hodna entre deux séries de montagnes au nord et au sud, organise le bassin autour d’une cuvette fermée presque plate à 400 m d’altitude dite Chott El Hodna (1 150 km²). Cette cuvette reçoit les apports liquides et solides des 17 oueds du Hodna dont l’Oued El ham est le plus grand drainant un sous bassin d’une superficie de 5604 km². Le climat de ce dernier est typiquement semi-aride, caractérisé par des précipitations irrégulières et agressives. Sa précipitation moyenne annuelle est de l’ordre de 185 mm associée à une forte variabilité (coefficient de variation interannuelle Cv = 40% pendant 38 années hydrologiques 1968-2006). Les apports liquides et solides de l’oued El ham sont mesurés par une station hydrométrique (appelée Rocad Sud) placée à l’exutoire du bassin. Dans cette étude, nous utilisons 1293 enregistrements instantanés de débits liquides et concentrations des sédiments en suspension, ce nombre de données couvre une période de 20 années hydrologiques 1968-1989. Oued El ham, transporte annuellement en moyenne 94 Millions de m3 d’eau (avec CV =1.2) et 2.97 millions de tonnes de sédiments (avec Cv =1.0), soit une charge spécifique des sédiments de l’ordre de 530 T/km²/an. La comparaison des résultats obtenus à d’autres bassins algériens montre que l’érosion hydrique dans ce bassin est parmi les plus importantes en Algérie, avec une variabilité interannuelle de l’ordre de 100%. Les apports de l’oued El ham sont déversés dans le chott Hodna (1150 km²), durant la période de cette étude de 21 ans, l’apport solide de l’oued El ham a contribué à l’élévation de la cote terrain du chott de 20 cm en moyenne. Ce qui menace les villages situés dans cette zone (Chelal, Baneou, Maarif…). L’analyse des données à l’échelle saisonnière montre que la plus grande partie de l’érosion hydrique (soit 31.72%) est observée en automne. A l’échelle mensuelle la variabilité est de l’ordre de 80%, durant la période de l’étude plus de la moitié du transport solide est observée en trois mois septembre (18.40%), avril (17.81%) et juin (18.82%). En fait, les crues de début d’automne et de fin de printemps sont responsables de la grande partie de l’érosion