Potential hazards and risks associated with the aquaculture industry

Aquaculture, the farming of aquatic organisms, is fraught with potential hazards and risks which are categorized into occupational, environmental, food safety and public health. This paper reviewed major hazards and risks associated with the aquaculture industry and proffered strategies for theirmanagement and control. Aquaculture stakeholders should therefore ensure that guidelines and policies which promote an environmentally friendly and sustainable industry are instituted and enforced

Genotype-Specific Differences between Mouse CNS Stem Cell Lines Expressing Frontotemporal Dementia Mutant or Wild Type Human Tau

Stem cell (SC) lines that capture the genetics of disease susceptibility provide new research tools. To assess the utility of mouse central nervous system (CNS) SC-containing neurosphere cultures for studying heritable neurodegenerative disease, we compared neurosphere cultures from transgenic mice that express human tau with the P301L familial frontotemporal dementia (FTD) mutation, rTg(tauP301L)4510, with those expressing comparable levels of wild type human tau, rTg(tauwt)21221. rTg(tauP301L)4510 mice express the human tauP301L variant in their forebrains and display cellular, histological, biochemical and behavioral abnormalities similar to those in human FTD, including age-dependent differences in tau phosphorylation that distinguish them from rTg(tauwt)21221 mice. We compared FTD-hallmark tau phosphorylation in neurospheres from rTg(tauP301L)4510 mice and from rTg(tauwt)21221 mice. The tau genotype-specific phosphorylation patterns in neurospheres mimicked those seen in mice, validating use of neurosphere cultures as models for studying tau phosphorylation. Genotype-specific tau phosphorylation was observed in 35 independent cell lines from individual fetuses; tau in rTg(tauP301L)4510 cultures was hypophosphorylated in comparison with rTg(tauwt)21221 as was seen in young adult mice. In addition, there were fewer human tau-expressing cells in rTg(tauP301L)4510 than in rTg(tauwt)21221 cultures. Following differentiation, neuronal filopodia-spine density was slightly greater in rTg(tauP301L)4510 than rTg(tauwt)21221 and control cultures. Together with the recapitulation of genotype-specific phosphorylation patterns, the observation that neurosphere lines maintained their cell line-specific-differences and retained SC characteristics over several passages supports the utility of SC cultures as surrogates for analysis of cellular disease mechanisms

GABA Expression and Regulation by Sensory Experience in the Developing Visual System

The developing retinotectal system of the Xenopus laevis tadpole is a model of choice for studying visual experience-dependent circuit maturation in the intact animal. The neurotransmitter gamma-aminobutyric acid (GABA) has been shown to play a critical role in the formation of sensory circuits in this preparation, however a comprehensive neuroanatomical study of GABAergic cell distribution in the developing tadpole has not been conducted. We report a detailed description of the spatial expression of GABA immunoreactivity in the Xenopus laevis tadpole brain at two key developmental stages: stage 40/42 around the onset of retinotectal innervation and stage 47 when the retinotectal circuit supports visually-guided behavior. During this period, GABAergic neurons within specific brain structures appeared to redistribute from clusters of neuronal somata to a sparser, more uniform distribution. Furthermore, we found that GABA levels were regulated by recent sensory experience. Both ELISA measurements of GABA concentration and quantitative analysis of GABA immunoreactivity in tissue sections from the optic tectum show that GABA increased in response to a 4 hr period of enhanced visual stimulation in stage 47 tadpoles. These observations reveal a remarkable degree of adaptability of GABAergic neurons in the developing brain, consistent with their key contributions to circuit development and function

Pharmacology and therapeutic implications of current drugs for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a global epidemic that poses a major challenge to health-care systems. Improving metabolic control to approach normal glycaemia (where practical) greatly benefits long-term prognoses and justifies early, effective, sustained and safety-conscious intervention. Improvements in the understanding of the complex pathogenesis of T2DM have underpinned the development of glucose-lowering therapies with complementary mechanisms of action, which have expanded treatment options and facilitated individualized management strategies. Over the past decade, several new classes of glucose-lowering agents have been licensed, including glucagon-like peptide 1 receptor (GLP-1R) agonists, dipeptidyl peptidase 4 (DPP-4) inhibitors and sodium/glucose cotransporter 2 (SGLT2) inhibitors. These agents can be used individually or in combination with well-established treatments such as biguanides, sulfonylureas and thiazolidinediones. Although novel agents have potential advantages including low risk of hypoglycaemia and help with weight control, long-term safety has yet to be established. In this Review, we assess the pharmacokinetics, pharmacodynamics and safety profiles, including cardiovascular safety, of currently available therapies for management of hyperglycaemia in patients with T2DM within the context of disease pathogenesis and natural history. In addition, we briefly describe treatment algorithms for patients with T2DM and lessons from present therapies to inform the development of future therapies

The effect of culture on Corporate Governance Practices in Nigeria

This study focuses on the effect of culture on the application of corporate governance practices in Nigeria. Corporate governance has been receiving serious attention in emerging markets over the past two decades. But relatively little attention has been given to the study on corporate governance in a country study. The current situations in Nigerian public and private sectors such as the corporate scandal resulting from Lever Brothers Nigeria plc, Siemens, Shell, Halliburton, and Cadbury Nigeria plc, have shown that the issue of fraud, corruption, and corporate scandals cannot be overlooked. Most top management, as this study argues, bring in beliefs acquired from their early childhood into their senior management roles and responsibilities. This study adopts a grounded theory and reports on the effect of culture on the implementation of corporate governance in Nigeria. Based on the interview with 32 staffs, this study identifies the effect of culture that shapes corporate governance and they include abuse of power by top management, weak legal framework, poor recruitment and ineffective control. Although having efficient corporate governance is worth pursuing, this depends on the power of top management, the strength of internal control procedures and the legal framework put in place by management

Toxicity of roundup (a glyphosate product) to fingerlings of Clarias gariepinus

 Acute static renewal bioassays were conducted on fingerling and adult of Clarias gariepinus (mean weight, 1.22 ± 0.6g; mean total length, 5.25 ± 1.25 cm) using the herbicide, Roundup (glyphosate). In the acute study, fingerlings were exposed in triplicate to 0.0, 14.0, 16.0, 18.0, 20.0 22.0, and 24.0 mg/l of the herbicide for 96 hours to determine general behavioural responses and specific responses (opercular beat frequency (OBF), tail beat frequency (TBF), lethal concentration (LC50) and median lethal time (MLT50). Exposed fish showed initial stress responses such as increased opercular ventilatory rate, dash and erratic swimming and gasping for air. The pattern of response of TBF to time and concentration of the herbicide was irregular, whereas that of OBF tended to decrease with increase in time, but increased with increase in concentration. Cumulative mortality values increased with exposure time. The effect of exposure time on the behavioural variables was: TBF (p > 0.05), OBF (p < 0.001) and cumulative mortality (p < 0.01) and that for concentrations were TBF (p > 0.05), OBF (p < 0.01) and cumulative mortality (p< 0.001). Interactions between time and concentration produced significant effect only in cumulative mortality (p < 0.01). The 96 hour LC50 of Roundup on the fish was 19.58 mg/l. The MLT50 decreased with exposure concentration with 24 mg/l killing half the exposed fish at 19.69 (17.41 - 21.94 CL) hours. Results from this study show that the herbicide cannot be described as having “low toxicity and being environmentally friendly” as suggested by the manufacturer, Monsanto

Haemogram of adult Clarias gariepinus exposed to chronic levels of roundup

Clarias gariepinus (mean weight, 850 ± 60 g) mean length, 38.75 ± 6.7 cm) were exposed individually to four concentrations of Roundup, containing 360g/l glyphosate in the form of 480g/l isopropylamine salt (1.5, 3.0, 4.5 and 6.0 mg/l) and a control (0 mg/l), five replicates per concentration for 70 days in static renewal boassay to determine the effect of exposure on selected blood variables (red blood cells, RBC; packed cell volume, PCV; white blood cell (WBC). thrombocytes, reticulocytes absolute red cell indices- mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC), leucocrit. Exposure to chronic levels of Roundup caused a reduction in the values of PCV, HB, ESR, thrombocytes, WBC, reticulocytes, RBC, MCV and MCH relative to the control. Response o the blood variablesamong the treated group varied very widely and was not directly related to concentration of herbicide except in thrombocytes. There was a reduction in the values of the variables involved in oxygen transport (PCV, Hb, RBC) and absolute red cel values in some of the exposed fish. Thrombocytes appeared to be the most responsive variable as the value was drastically reduced from 1060 x 109 cells/l at 1.50 mg/l to 122.50 x 109 cells/l at 6.0 mg/l. It was only in the ESR that the value in the control (0.25 mmhr-1) was significantly different from that of the treated groups (6.0 mmhr-1 at 6.0 mg/l). The regression lines of best fit for the relationship between the herbicide concentration and the various variables showed that the responses of the test fish to the herbicide varied as indicatedby the curve types. The response of adult C. gariepinus to subethal concentrations of Roundup suggest that the fish could be under ntense physiological stress in the wild and culture conditions where the herbicide is applied at the recommended rate (liquid, 12l/ha; solid, 2.2 kg/ha) without the least effort to maintain the maximum recommended 0.6 mg/l in 1m water column after application

Effects of Dietary Inclusions of Whole Cassava Root Meal on the Hematology of Hybrid Catfish

This experiment was conducted on the possibility of replacing maize (Zea mays) with varying levels of whole cassava (Manihot esculenta) root meal (WCRM) at 0(Ao) 33(B33), 66(C66), and 100(D100)% inclusions in the diet of hybrid catfish fingerlings for a period of 32 weeks. The fish were fed twice daily at 5% body weight. At the end of the trial, some hematological parameters of the fish were assessed. The results obtained, showed that the treatment caused a significant increase (p<0.05) in the blood glucose and mean corpuscular volume (MCV). The values of hemoglobin (Hb), packed cell volume (PCV), platelets (PLT), and mean corpuscular hemoglobin (Hb), packed cell volume (PCV), platelets (PLT), and mean corpuscular hemoglobin (MCH) were also raised in the treated groups above the control value. The highest values of Hb (10.16±1.0 g/dl), PCV (44.33± 3.4%), PLT (508.17±235.41 cells x 109/L) and erythrocyte sedimentation rate (ESR) (3.00±4.90 pg) were recorded at 66% inclusion level indicating a stress free condition of the fish. Keywords: Catfish, maize, cassava root meal, hematolog