Cardiac function and blood flow hemodynamics assessment of zebrafish (Danio rerio) using high-speed video microscopy.

BACKGROUND: In the last few decades, zebrafish (Danio rerio) were introduced as a model organism to investigate human diseases including cardiovascular and neuronal disorders. In most zebrafish investigations, cardiac function and blood flow hemodynamics need to be assessed to study the effects of the interference on the cardiovascular system. For heart function assessment, most important parameters include heart rate, cardiac output, ejection fraction, fractional area change, and fractional shortening. METHODS: A 10 s high-speed video of beating heart and flowing blood within major vessels of zebrafish that are less than 5 days post fertilization (dpf) were recorded via a stereo microscope equipped with a high speed camera. The videos were analyzed using MicroZebraLab and image J software for the assessment of cardiac function. RESULTS: Using the technique described here, we were able to simply yet effectively assess cardiac function and blood flow dynamics of normal zebrafish embryos. We believe that the practical method presented here will help cardiac researchers using the zebrafish as a model to examine cardiac function by using tools that could be available in their laboratory.

The prevalence and trends of overweight, obesity and nutrition-related non-communicable diseases in the Arabian Gulf States.

This paper reviews studies on the prevalence of overweight, obesity and related nutrition-related non-communicable diseases in Bahrain, Kuwait, Qatar, Oman, Saudi Arabia and the UAE. Obesity is common among women; while men have an equal or higher overweight prevalence. Among adults, overweight plus obesity rates are especially high in Kuwait, Qatar and Saudi Arabia, and especially among 30-60 year olds (70-85% among men; 75-88% among women), with lower levels among younger and elderly adults. The rate of increase in obesity was pronounced in Saudi Arabia and Kuwait. Prevalence of obesity is high among Kuwaiti and Saudi pre-schoolers (8-9%), while adolescent overweight and obesity are among the highest in the world, with Kuwait having the worst estimates (40-46%); however, comparison of child data is difficult because of differing standards. Among nutrition-related non-communicable diseases, hypertension and diabetes levels are very high and increase with age, with the UAE performing the worst because of a rapid rate of increase between 1995 and 2000. Additional monitoring of the prevalence of metabolic syndrome and cancers is necessary. Nationally representative longitudinal surveys with individual, household and community-level information are needed to determine the importance of various factors that contribute to these troubling trends.

Enzyme-catalyzed removal of phenol from refinery wastewater: feasibility studies.

Phenols are present in petroleum refining wastewater. An enzymatic method for removing phenols from industrial aqueous effluent has been developed in the past several years. In this method, a peroxidase enzyme catalyzes the oxidation of phenol by hydrogen peroxide generation of phenoxyl radicals. These radicals diffuse from the active center of the enzyme into solution and react nonenzymatically to eventually form higher oligomers and polymers, which can be removed from wastewater by conventional coagulation and sedimentation or filtration. In this study, Arthromyces ramosus peroxidase (ARP) was applied to treat a petroleum refining wastewater containing 2 mM (188 mg/L) phenol in a batch and continuous-flow system. The latter consisted of a plug-flow reactor (PFR) where the reaction took place between phenol and hydrogen peroxide catalyzed by the enzyme in the presence of polyethylene glycol (PEG). A flocculation tank followed the PFR where alum and sodium hydroxide were added and then the polymers formed were settled in a sedimentation tank and removed from the system. Most (95 to 99%) of the phenol was removed by the same dose of ARP required for the treatment of synthetic wastewater containing an equal amount of phenol. Polyethylene glycol, as an additive, reduced enzyme inactivation and consequently reduced the enzyme dose and the cost of the treatment process. Step feeding of hydrogen peroxide was not effective in reducing the enzyme requirement. A significant removal of chemical oxygen demand was achieved when using PEG to reduce the enzyme dose.

Management of wastewater from soap and food industries: a case study.

This paper presents the wastewater management of an industrial complex which produces different products, i.e. soap, perfume extract, macaroni, jam and juices. A continuous monitoring programme for departmental as well as final effluents was carried out for almost 3 months. Characterization of the composite wastewater from both soap and food processing plants indicated that the waste was highly contaminated with organic compounds as indicated by COD and BOD values. Moreover, effluent from the soap manufacturing plant contains significant concentrations of oil and grease amounting to 563 mg l-1. Soap manufacturing effluent and the combined wastes discharged from the whole industrial complex were subjected to different treatment processes, namely dissolved air flotation, chemical coagulation-sedimentation, and biological treatment via a completely mixed activated sludge process. Although coagulation using alum followed by sedimentation removed 52% of COD, residual values did not comply with the regulatory standards. Biological treatment of the composite combined wastewater significantly removed the organic contaminants in wastewater. Average residual BOD, COD, oil and grease values were 30, 92 and 8.3 mg l-1 respectively. Based on the laboratory results a final process design was developed.