Application of biotechnology in fish breeding. II: production of highly immune genetically modified redbelly tilapia, Tilapia zillii

The present study aims to produce a highly immune, genetically modified redbelly tilapia, Tilapia zillii with accelerated growth as a result of direct injection of shark (Squalus acanthias L.) DNA into skeletal muscles of fish fingerlings at concentrations of 10, 20, 40 and 80 μg/fish. The results showed that the fish injected with 40 μg/fish had significant (P&le0.05) superiority of growth performance. Also, the body composition of these fish was improved. The fish injected with 20 and 40 μg/fish had significant (P&le0.05) higher means of total antibody activity (total IgM), serum total protein and globulin compared with other injected groups. Cytological examination for all injected fish and their control revealed the same diploid number (2n=44) of chromosomes, and no chromosomal abberations were detected. Moreover, DNA fingerprinting showed high polymorphism among injected fish. Therefore, variable fragments of shark DNA may randomly integrated into T. zillii muscle genomes. The present investigation revealed also that egg diameters of injected females and their control were divided into nine groups, which varied between 0.2 and 1.7 mm. In addition, ovary of T. zillii females injected with 10; 20; 40 and 80 μg/fish of shark DNA showed 10, 38, 65 and 18% normal oocytes, respectively. Also, test of males injected with various amounts of DNA showed large number of abnormalities. Moreover, the comparison between all injected fish revealed that the testes and ovaries of fish injected with 80 μg/fish were more deformed and atretic. This means that the effects of intramuscular direct injection of foreign DNA into T. zillii could be limited to germ cells of fish. Therefore, further studies about the establishment of these effects on the following generations are needed. The result indicates a possible easy and rapid way for improving fish characteristics.African Journal of Biotechnology Vol. 4 (5), pp. 449-459, 200

MDCT assessment of HCC patient after radiofrequency ablation among Egyptian population: Preliminary experience

Purpose: Evaluate the role of multi-detector computed tomography (MDCT) in follow up HCC patients after radiofrequency ablation. Materials and methods: A prospective study was used to assess patients who underwent radiofrequency ablation for treatment of HCC nodules using MDCT. MDCT was done immediately after procedure to asses treatment success, then after one month for decision making; either good ablation or reablation for residual tumor if present. Three and six months follow up for detection of marginal growth or newly developed HCC nodules. One year MDCT follow up for true technical success. Results: MDCT findings were as follows: immediate evaluation showed good ablation in 29 patients (96.7%), and one patient showed residual tumor tissue reablated at the same session. In one month follow up nodular marginal enhancement denoting residual tumor was seen in 2 patients (6.7%). In three months follow up no residual tumor or recurrence (100%); in six months follow up recurrence was seen in one patient (3.4%) and another patient (3.4%) showed a new HCC focus. In one year follow up marginal recurrence was seen in three patients (10%). Conclusion: RF ablation is an internationally approved treatment for HCC. MDCT should be the corner stone method for follow to achieve better results and improve the survival rate via early detection and immediate interference with any new or recurrent lesions

On laser welding of thin steel sheets

International audienceThis paper presents a process-structure-property relationship study of laser welds as a continuous consolidation method for joining thin monophased steel foils, thereby providing a more effective, less costly method to construct automotive catalytic converters. A body centred cubic (bcc) iron-chromium-aluminium alloy doped with Mischmetal was utilised in this study. Both pulsed and continuous wave modes were used to establish the limit welding diagrams for lap joint configuration. Actual laser welding parameters were selected using several testing conditions. The laser welds behaved substantially different from the base material under creep and high temperature oxidation. The difference was mainly attributed to the changes in grain morphology, precipitation of aluminium nitrides and carbides, and relocalisation of the reactive elements during liquid metal flow upon keyhole formation, solidification and cooling

Sharing aquatic genetic resources across jurisdictions: playing ‘chicken’ in the sea

International regimes regulating access and benefit sharing were originally designed to promote conservation and fairness objectives concerning the use of the world’s biological resources for their genetic material value. These regimes determine from whom permission is required to take the resources and who obtains the benefits of their use. They have evolved separate frameworks in three distinct jurisdictional areas—within national jurisdiction, beyond national jurisdiction and in the Antarctic Treaty Area. This article argues that if these regimes continue to evolve separately, there is a strong temptation for countries to play ‘chicken’ with biological resource governance through forum shopping or opting out of agreements that do not suit their political ends. Using game theory and a transgenic tilapia fish example incorporating genetic material from the three jurisdictional areas, it illustrates the legal and ethical dilemmas that can arise from the territorial (jurisdictional) approach to access and benefit sharing—to the detriment of fairness and conservation in tilapia’s countries of origin. Tilapias are known as the ‘chicken of the sea’ because they dominate global farmed production and developing countries depend on them as their primary source of protein, livelihoods and trade. This means there will be serious consequences if the regimes do not achieve their fairness and conservation objectives for sharing their genetic material. This article concludes that a purpose-driven cooperative governance approach can sidestep the game of chicken and promote fairer and more conservation focused outcomes than the current jurisdictional approach for the developing country providers of migratory aquatic resources