Shymaa E. Bilasy

Dorsal telencephalon‐specific RA‐GEF‐1 knockout mice develop heterotopic cortical mass and commissural fiber defect

Neural migration defects lead to various types of human malformations of cortical development including subcortical band heterotopia, which shows formation of a secondary cortical plate beneath the primary cortex and is typically caused by mutation of the DCX (doublecortin) gene. Subcortical band heterotopia is usually associated with mental retardation and epilepsy. We previously discovered RA‐GEF‐1 as a guanine nucleotide exchange factor (GEF) for Rap1 small GTPase. Here we have analysed its in‐vivo role in formation of the adult cerebral cortex by using telencephalon‐specific RA‐GEF‐1 conditional knockout (cKO) mice, generated by mating RA‐GEF‐1flox/flox mice with Emx1‐cre knockin mice. RA‐GEF‐1 cKO mice showed severe defects in their brain structures including an ectopic cortical mass underlying a relatively normal cortex. The ectopic cortical mass lacked the normal six‐layered lamination but preserved the subcortical connectivity as revealed by retrograde tracing. Further, RA‐GEF‐1 cKO mice exhibited a lower threshold for the induction of epileptic seizures. These phenotypes have a resemblance to those of human subcortical band heterotopia. In addition, the agenesis of anterior commissures, the dorsal hippocampus commissure, the corpus callosum and the enlargement of the lateral ventricles were observed in cKO mice. Our findings suggest a crucial function of RA‐GEF‐1 in neural migration.

Medical management of patients after bariatric surgery: Principles and guidelines

Obesity is a major and growing health care concern. Large epidemiologic studies that evaluated the relationship between obesity and mortality, observed that a higher body-mass index (BMI) is associated with increased rate of death from several causes, among them cardiovascular disease; which is particularly true for those with morbid obesity. Being overweight was also associated with decreased survival in several studies. Unfortunately, obese subjects are often exposed to public disapproval because of their fatness which significantly affects their psychosocial behavior. All obese patients (BMI ≥ 30 kg/m(2)) should receive counseling on diet, lifestyle, exercise and goals for weight management. Individuals with BMI ≥ 40 kg/m(2) and those with BMI > 35 kg/m(2) with obesity-related comorbidities; who failed diet, exercise, and drug therapy, should be considered for bariatric surgery. In current review article, we will shed light on important medical principles that each surgeon/gastroenterologist needs to know about bariatric surgical procedure, with special concern to the early post operative period. Additionally, we will explain the common complications that usually follow bariatric surgery and elucidate medical guidelines in their management. For the first 24 h after the bariatric surgery, the postoperative priorities include pain management, leakage, nausea and vomiting, intravenous fluid management, pulmonary hygiene, and ambulation. Patients maintain a low calorie liquid diet for the first few postoperative days that is gradually changed to soft solid food diet within two or three weeks following the bariatric surgery. Later, patients should be monitored for postoperative complications. Hypertension, diabetes, dumping syndrome, gastrointestinal and psychosomatic disorders are among the most important medical conditions discussed in this review.

NS5A Sequence Heterogeneity of Hepatitis C virus Genotype 4a Predicts Clinical Outcome of Pegylated-Interferon/Ribavirin Therapy in Egyptian Patients

ABSTRACT Hepatitis C virus genotype 4 (HCV-4) is the cause of approximately 20% of the 180 million cases of chronic hepatitis C in the world. HCV-4 infection is common in the Middle East and Africa, with an extraordinarily high prevalence in Egypt. Viral genetic polymorphisms, especially within core and NS5A regions, have been implicated in influencing the response to pegylated-interferon and ribavirin (PEG-IFN/RBV) combination therapy in HCV-1 infection. However, this has not been confirmed in HCV-4 infection. Here, we investigated the impact of heterogeneity of NS5A and core proteins of HCV-4, mostly subtype HCV-4a, on the clinical outcomes of 43 Egyptian patients treated with PEG-IFN/RBV. Sliding window analysis over the carboxy terminus of NS5A protein identified the IFN/RBV resistance-determining region (IRRDR) as the most prominent region associated with sustained virological response (SVR). Indeed, 21 (84%) of 25 patients with SVR, but only 5 (28%) of 18 patients with non-SVR, were infected with HCV having IRRDR with 4 or more mutations (IRRDR ≥ 4) (P = 0.0004). Multivariate analysis identified IRRDR ≥ 4 as an independent SVR predictor. The positive predictive value of IRRDR ≥ 4 for SVR was 81% (21/26; P = 0.002), while its negative predictive value for non-SVR was 76% (13/17; P = 0.02). On the other hand, there was no significant correlation between core protein polymorphisms, either at residue 70 or at residue 91, and treatment outcome. In conclusion, the present results demonstrate for the first time that IRRDR ≥ 4, a viral genetic heterogeneity, would be a useful predictive marker for SVR in HCV-4 infection when treated with PEG-IFN/RBV.

RA-GEF-1 (Rapgef2) is essential for proper development of the midline commissures.

The cerebral hemispheres are directly connected by three major interhemispheric fibers: the corpus callosum, the anterior commissure, and the hippocampal commissure. RA-GEF-1 (also termed Rapgef2) is a guanine nucleotide exchange factor responsible for sustained activation of Rap1. We previously reported anatomical defects of the major forebrain commissures in the adult dorsal telencephalon-specific RA-GEF-1 conditional knockout (cKO) mice. In this study, we use neuroanatomical tracing and immunohistochemistry to study the formation of the commissural fibers during early postnatal development. DiI anterograde tracing reveals the inability of the callosal axons to cross the midline in cKO mice, thereby forming Probst bundles on the ipsilateral side, which is associated with the absence of the indusium griseum glia and the glial sling at the cortical midline. Wheat germ agglutinin-conjugated horseradish peroxidase retrograde tracing verifies the agenesis of the anterior commissure in cKO mice, and DiI anterograde tracing confirms the deviation of the fibers from their original tract. As for the hippocampal commissure, agenesis and hypoplasia are observed in its dorsal and ventral parts, respectively. These results indicate the essential role of RA-GEF-1 in the proper formation of the cerebral midline commissures.

Prior to the oral therapy, what do we know about HCV-4 in Egypt: a randomized survey of prevalence and risks using data mining computed analysis.

AbstractHepatitis C virus (HCV) affects over 180 million people worldwide and its the leading cause of chronic liver diseases and hepatocellular carcinoma. HCV is classified into seven major genotypes and a series of subtypes. In general, HCV genotype 4 (HCV-4) is common in the Middle East and Africa, where it is responsible for more than 80% of HCV infections. Although HCV-4 is the cause of approximately 20% of the 180 million cases of chronic hepatitis C worldwide, it has not been a major subject of research yet. The aim of the current study is to survey the morbidities and disease complications among Egyptian population infected with HCV-4 using data mining advanced computing methods mainly and other complementary statistical analysis.Six thousand six hundred sixty subjects, aged between 17 and 58 years old, from different Egyptian Governorates were screened for HCV infection by ELISA and qualitative PCR. HCV-positive patients were further investigated for the incidence of liver cirrhosis and esophageal varices. Obtained data were analyzed by data mining approach.Among 6660 subjects enrolled in this survey, 1018 patients (15.28%) were HCV-positive. Proportion of infected-males was significantly higher than females; 61.6% versus 38.4% (P = 0.0052). Around two-third of infected-patients (635/1018; 62.4%) were presented with liver cirrhosis. Additionally, approximately half of the cirrhotic patients (301/635; 47.4%) showed degrees of large esophageal varices (LEVs), with higher variceal grade observed in males. Age for esophageal variceal development was 47 ± 1. Data mining analysis yielded esophageal wall thickness (>6.5 mm), determined by conventional U/S, as the only independent predictor for esophageal varices.This study emphasizes the high prevalence of HCV infection among Egyptian population, in particular among males. Egyptians with HCV-4 infection are at a higher risk to develop cirrhotic liver and esophageal varices. Data mining, a new analytic technique in medical field, shed light in this study on the clinical importance of esophageal wall thickness as a useful predictor for risky esophageal varices using decision tree algorithm.

Impaired vascular development in the yolk sac and allantois in mice lacking RA-GEF-1

RA-GEF-1 is a guanine nucleotide exchange factor for the small GTPase Rap1. RA-GEF-1 knockout mice show defects in vascular development starting around 7.5days post coitum and die by 9.5days post coitum. Here, we employed in vitro culture systems for allantois explants and endothelial cells to gain insights into the mechanism for RA-GEF-1-mediated regulation of embryonic vascular network formation. The development of the vascular plexus and the accumulation of VE-cadherin at cell-cell junctions were significantly impaired in the RA-GEF-1 knockout allantois and yolk sac. Rap1 activation as visualized by an activation-specific probe was also diminished by RA-GEF-1 knockout. Reduced accumulation of VE-cadherin at cell-cell junctions and defects in blood vessel formation in vitro due to the lack of RA-GEF-1 were suppressed by ectopic expression of constitutively activated Rap1. Overall, these results suggest the involvement of Rap1 downstream of RA-GEF-1 in the regulation of vascular network formation in mouse embryos.

Myelosuppressive and hepatotoxic potential of leflunomide and methotrexate combination in a rat model of rheumatoid arthritis

BACKGROUND Safety of the combination of leflunomide and methotrexate was examined in several studies with inconclusive results. The present study was designed to compare the efficacy and safety of the combination of leflunomide and methotrexate in adjuvant-induced arthritis (AIA) in rats focusing on immunosuppressive and hepatotoxic effects. METHODS Eighty four rats were divided into seven groups. Group 1: Sham control, group 2: the vehicle control, group 3: methotrexate group, group 4-5: leflunomide (5 and 10mg/kg/day) groups, group 6-7: combination 1 and 2 [methotrexate+leflunomide (5 and 10mg/kg/day)] groups, respectively. RESULTS The current results indicated that combination therapies improved the ankle circumference and clinical scores compared to monotherapies; histopathological examination confirmed these findings. The myelosuppressive effect of leflunomide (10mg/kg/day) was comparable to that produced by methotrexate as indicated by the complete blood count and bone marrow cellularity; however their combination resulted in greater toxicity. Furthermore, methotrexate greatly affected the splenic histopathology compared to leflunomide and the combination therapy produced a greater effect compared to leflunomide not methotrexate. Differently, assessment of the hepatotoxic potential of the two drugs highlighted that leflunomide induced a dose-dependent increase in the fibrosis score which was higher in their magnitude than that induced by methotrexate. Leflunomide (10mg/kg/day) and combination 2 groups showed the greatest degree of liver fibrosis. CONCLUSIONS In rats with AIA, current drug combinations provided higher therapeutic benefit compared to monotherapies, however, greater toxicities were observed. Therefore, continuous monitoring of hematologic parameters and liver function will be recommended in clinical settings.

Detection of risky esophageal varices by two-dimensional ultrasound: when to perform endoscopy.

Objective:Esophageal varices are a consequence of portal hypertension in cirrhotic patients. Current guidelines recommend that all cirrhotic patients undergo screening endoscopy at diagnosis to identify patients with varices at high risk of bleeding who will benefit from primary prophylaxis. This practice increases costs, involves a degree of invasiveness and discomfort and places a heavy burden on endoscopy units. Several studies have evaluated possible noninvasive predictors of esophageal varices, but most of these studies remain controversial. Methods:The intra-abdominal portion of the esophagus in 673 patients who presented with liver cirrhosis and portal hypertension was examined using standard 2-dimensional (2D) ultrasound. A direct relationship between the degree of varices observed on upper endoscopy and the intra-abdominal esophageal wall thickness was detected using 2D ultrasound. Results:The mean thicknesses of the esophageal wall were 3.7 ± 0.5 mm (mean ± standard deviation) in normal individuals, 7.3 ± 3.3 mm in those with esophageal varices and 8.65 ± 1.98 mm in those with risky esophageal varices. The overall accuracy of 2D ultrasound was 95%. Conclusions:The intra-abdominal esophagus should be observed during abdominal ultrasound examination in patients with liver cirrhosis. Two-dimensional ultrasound can play an important role in screening for esophageal varices.

Crucial Role of Rapgef2 and Rapgef6, a Family of Guanine Nucleotide Exchange Factors for Rap1 Small GTPase, in Formation of Apical Surface Adherens Junctions and Neural Progenitor Development in the Mouse Cerebral Cortex

Abstract Cerebral neocortex development in mammals requires highly orchestrated events involving proliferation, differentiation, and migration of neural progenitors and neurons. Rapgef2 and Rapgef6 constitute a unique family of guanine nucleotide exchange factors for Rap1 small GTPase, which is known to play crucial roles in migration of postmitotic neurons. We previously reported that conditional knockout of Rapgef2 in dorsal telencephalon (Rapgef2-cKO) resulted in the formation of an ectopic cortical mass (ECM) resembling that of subcortical band heterotopia. Here we show that double knockout of Rapgef6 in Rapgef2-cKO mice (Rapgef2/6-dKO) results in marked enlargement of the ECM. While Rapgef2-cKO affects late-born neurons only, Rapgef2/6-dKO affects both early-born and late-born neurons. The Rapgef2-cKO cortex at embryonic day (E) 15.5, and the Rapgef2/6-dKO cortex at E13.5 and E15.5 show disruption of the adherens junctions (AJs) on the apical surface, detachment of radial glial cells (RGCs) from the apical surface and disorganization of the radial glial fiber system, which are accompanied by aberrant distribution of RGCs and intermediate progenitors, normally located in the ventricular zone and the subventricular zone, respectively, over the entire cerebral cortex. Moreover, intrauterine transduction of Cre recombinase into the Rapgef2flox/flox brains also results in the apical surface AJ disruption and the RGC detachment from the apical surface, both of which are effectively suppressed by cotransduction of the constitutively active Rap1 mutant Rap1G12V. These results demonstrate a cell-autonomous role of the Rapgef2/6-Rap1 pathway in maintaining the apical surface AJ structures, which is necessary for the proper development of neural progenitor cells.

The Value of U/S to Determine Priority for Upper Gastrointestinal Endoscopy in Emergency Room.

AbstractIn countries endemic for liver and GIT diseases, frequent emergency department (ED) patients contribute to a disproportionate number of visits consuming substantial amount of medical resources. One of the most frequent ED visits is patients who present with hypovolemic shock, abdominal pain, or confusion with or without signs of upper gastrointestinal bleeding (UGIB). The use of conventional two-dimensional ultrasound (2D-U/S) may provide immediate and useful information on the presence of esophageal varices, gastrointestinal tumors, and other GIT abnormalities.The current study investigated the feasibility of using (2D-U/S) to predict the source of UGIB in ED and to determine patients’ priority for UGE.Between February 2003 and March 2013, we retrospectively reviewed the profiles of 38,551 Egyptian patients, aged 2 to 75 years old, who presented with a history of GI/liver diseases and no alcohol consumption. We assessed the value of 2D-U/S technology in predicting the source of UGIB.Of 38,551 patients presenting to ED, 900 patients (2.3%), 534 male (59.3%) and 366 female (40.7%) developed UGIB. Analyzing results obtained from U/S examinations by data mining for emergent UGE were patients with liver cirrhosis (LC), splenomegaly, and ascites (42.6% incidence of UGIB), followed by LC and splenomegaly (14.6%), LC only (9.4%), and was only 0.5% who had no morbidity finding by 2D-U/S.Ultrasonographic instrumentation increases the feasibility of predictive emergency medicine. The area has recently not only gained a fresh impulse, but also a new set of complex problems that needs to be addressed in the emergency medicine setting according to each priority.