The Molecular Basis of Radial Intercalation during Tissue Spreading in Early Development

Radial intercalation is a fundamental process responsible for the thinning of multilayered tissues during large-scale morphogenesis; however, its molecular mechanism has remained elusive. Using amphibian epiboly, the thinning and spreading of the animal hemisphere during gastrulation, here we provide evidence that radial intercalation is driven by chemotaxis of cells toward the external layer of the tissue. This role of chemotaxis in tissue spreading and thinning is unlike its typical role associated with large-distance directional movement of cells. We identify the chemoattractant as the complement component C3a, a factor normally linked with the immune system. The mechanism is explored by computational modeling and tested in vivo, ex vivo, and in vitro. This mechanism is robust against fluctuations of chemoattractant levels and expression patterns and explains expansion during epiboly. This study provides insight into the fundamental process of radial intercalation and could be applied to a wide range of morphogenetic events

Irrigation and drainage in the new millennium

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Includes bibliographical references.A field study was conducted at Mashtul Pilot Area MPA (260 feddans' 1 feddan = 4200 m2) situated at north Zagazig to evaluate the performance of the long term constructed subsurface drainage system. The evaluation of grades, alignment and clogging of drain lines can give an indication of the system performance and efficiency. Three drainage units served by the same collector were selected. Four 30 m interval PVC lateral pipes were installed at different depths. The results revealed that, the collector drain slopes were either steep or flat while the overall slope of the collector drain was considered steep for about 45.50% of the sections and flat for the rest. On the other hand, some sections showed an inverse slope which can cause a decrease in the discharge rate. The regularity was classified as good for about 82% of the sections and moderate for the rest. The slope of the lateral drains was correct for 41.7% of those under study (12 lateral drains), steep for 16.60%, and flat for the rest, and the regularity was classified as poor except lateral number 71 which had moderate regularity in the first approach while, in the second approach 41.67% had moderate regularity and poor for the rest. Also the deviation of the drain pipes from the straight line was generally larger than pipe diameter. Consequently, air entrapment and sedimentation resulted. The results also indicated that, the average height of sedimentation inside lateral drains was 12.70 mm (618.30 gm/m drain length) while for collector drains, sediment was in 22.88% of pipe diameter. The average reduction in discharge capacity due to sedimentation for laterals and collectors upstream and downstream parts were 17.17%, 32.80% and 17.60% respectively. Also using Manning, Visser and Wesseling equations leads to different safety factors

Learning Radiology in an Integrated Problem-Based Learning (PBL) Curriculum

Background: The Faculty of Medicine (FoM) has been training health professions in Uganda since 1924. Five years ago, it decided to change the undergraduate curriculum from traditional to Problem Based Learning (PBL) and adopted the SPICES model. Radiology was integrated into the different courses throughout the 5 year program. The objective was to improve the implementation of the integration of Radiology in the integrated PBL curriculum.Methods: This was a cross sectional descriptive study of radiologists and medical students using interviews and semi-structured questionnaires respectively.Results: Radiologists’ and students’ perceptions and opinions on Radiology training were gathered. A Radiology training rationale was developed. Learning outcomes for Radiology were defined and learning formats were chosen. Learning materials were identified and strategies to improve the implementation were formulated.Conclusions: This work has culminated into changes in Radiology integration in the curriculum and training at the FOM

Mannose-binding lectin deficiency in preterm neonates

Background: Mannose-binding lectin (MBL) is a collagenous protein that plays a role in innate immunity. MBL deficiency is associated with an opsonization defect and has been associated with recurrent infections, especially in immunocompromised individuals. Neonates are considered to be immunocompromised because adaptive immunity has not yet been developed. Objective: This study was done to evaluate the levels of MBL in premature neonates and to determine the relation between MBL deficiency and development of sepsis. Methods: This case- control study was conducted on 64 neonates classified into 2 groups; 39 preterm neonates with gestational age (G.A) <36 weeks and 25 healthy full term neonates. Measurement of mannose-binding lectin (MBL) serum level was done on the first day of life using ELISA technique. Results: Mean MBL plasma level was found to be lower in preterm than full term neonates, yet this difference did not reach statistical significance. There was a negative correlation albeit an insignificant one, between MBL level and GA. The deficient group (those with MBL level ≤0.7μg/ml) had higher incidence of sepsis, albeit an insignificant one, than the non deficient group. A highly significant positive correlation was demonstrated between MBL plasma level in neonatal and umbilical cord blood samples. Conclusion: Premature neonates have low MBL serum levels which could be measured in either their venous or umbilical cord blood efficiently. Further studies are needed to investigate the relationship between MBL deficiency and neonatal sepsis and whether measuring MBL levels might be used to identify which neonates are prone to infections.Keywords: Mannose binding lectin, neonates, preterm, sepsisEgypt J Pediatr Allergy Immunol 2010;8(2):75-8

Homocysteine, folic acid and vitamin B12 levels in serum of epileptic children

AbstractThe relationship between increased homocysteine (Hcy) level and epileptic seizure remains controversial in human, despite a growing evidence of the pro-convulsive effect of the hyperhomocysteinemia (HHcy) observed in the animal studies. The mechanism of this association with epileptogenesis has not been clearly understood, although there is emerging evidence to support the unfavorable effects of some anti-epileptic drugs (AEDs) on the plasma homocysteine (Hcy) concentrations. The aim of this study was to uncover the relationship between the levels of homocysteine (Hcy), the cofactors involved in its metabolism as folic acid and vitamin B12 and anti-epileptic drugs (AEDs) in epileptic patients. Serum level of homocysteine (Hcy), folic acid and vitamin B12 was measured in 60 patients with idiopathic epilepsy; and its level was compared to 30 healthy children serving as control group. No significant difference was found regarding the plasma homocysteine (Hcy) levels between patients (both receiving anti-epileptics and non anti-epileptic drug users) and controls. Epileptic patients on polytherapy showed higher mean serum levels of homocysteine (Hcy) and lower mean serum levels of folic acid compared to those on monotherapy. However, the mean serum levels of homocysteine (Hcy), vitamin B12 and folic acid showed non significant differences between patients using valproic acid (VPA) or carbamazepine (CBZ). Duration of AED therapy showed a significant positive correlation with mean serum levels of homocysteine (Hcy) and a significant negative correlation with mean serum levels of folic acid. To conclude; AEDs upset the homeostatic balance of homocysteine (Hcy) and its cofactors and cause abnormalities in their serum levels

POSSIBLE PROTECTIVE ROLE OF SODIUM SALICYLATE NANOEMULSION AND GINGER ON CISPLATIN‑INDUCED HEPATOTOXICITY IN RATS (BIOCHEMICAL AND HISTOPATHOLOGICAL STUDY)

Objective: To describe the preparation and characterization of nanoemulsion of sodium salicylate loaded butane tetracarboxylic acid (Bt-Sc-NPs). It also investigates the possible protective effects of Bt-Sc-NPs and\or medicinal plant ginger to evaluate the changes of liver functions, oxidative stress and histopathological investigations against cisplatin-induced hepatotoxicity. Methods: Serum was used to determine alanine aminotransferase (ALT), aspartate aminotransferase (AST), δ-glutamyl transferase (δGT), serum human laminin (LN) and tissue inhibitors of metalloproteinase1 (TIMP1). Liver tissue samples collected from the rats were used for the measurement of malondialdehyde (MDA), nitric oxide (NO) and paraoxonase 1 (PON1). Results: The beneficial effects of Bt-Sc-NPs with its anti-inflammatory effect and the medicinal ginger with its antioxidant effect were observed. Injection of rats with cisplatin significantly increased serum ALT, AST, ɤGT, TIMP1 and LN. It also increased cisplatin-induced oxidative stress by a significant elevation in liver MDA, NO content; however, a significant decrease of PON1 content. While protection with Bt-Sc-NPs or ginger significantly improved these parameters. In addition, combination of both Bt-Sc-NPs and ginger significantly induced a decrease in serum ALT, AST, ɤGT, TIMP1 and LN. It also reduced cisplatin-induced oxidative stress by the significant reduction in liver MDA, NO content and elevation of PON1 content much more than protection with Bt-Sc-NPs or ginger alone. Conclusion: Bt-Sc-NPs were synthesized using nanoemulsion with the help of homogenization and ultra-sonication waves. Combination with both of Bt-Sc-NPs and ginger showed a hepatoprotective role in ameliorating cisplatin‑induced hepatotoxicity due to their anti-inflammatory and antioxidant effects