Plasma concentrations of water.soluble vitamins in metabolic syndrome subjects

Context: Vitamins B1 (thiamine), B3 (niacin), B6 (pyridoxine), and C (ascorbic acid) are vital for energy, carbohydrate, lipid, and amino acid metabolism and in the regulation of the cellular redox state. Some studies have associated low levels of water.soluble vitamins with metabolic syndrome and its various components.Aims: This study aims to determine the plasma concentrations of vitamins B1, B3, B6, and C in Nigerians with metabolic syndrome and in healthy controls.Settings and Design: One.hundred subjects with metabolic syndrome were recruited into the study. One.hundred controls were age ..and sex.matched.Materials and Methods: Blood pressure, body mass index, waist circumference, concentrations of plasma glucose, lipid profile, and vitamins B1, B3, B6, and C were estimated.Statistical analysis used: Statistical Package for Social Sciences (SPSS) version 11.0.Results: The mean plasma vitamins B1, B3, B6, and C concentrations of subjects were significantly lower than that of controls (P = 0.001, 0.05, 0.045, 0.001 respectively). Fourteen percent and 32% of subjects had inadequate vitamins B1 and C status, respectively. Vitamin B6 was lower (P = 0.001) and vitamin C was higher (P = 0.012) in female thanin male subjects.Conclusions: Thiamine, niacin, pyridoxine, and ascorbic acid levels were lower in subjects than in controls. Pyridoxine was also lower and ascorbic acid was higher in female than in male subjects

Antioxidant status of type 2 diabetic patients in Port Harcourt, Nigeria

Context: Oxidative stress has been implicated in the pathogenesis of type 2 diabetes mellitus (T2M) and its complications. Aims: This study was conducted to determine and compare total antioxidant status (TAS), vitamin C and E levels in T2DM patients and healthy control subjects. Settings and Design: Fifty‑five previously diagnosed DM patients aged between 34 years and 70 years and 50 control subjects aged between 35 years and 69 years were consecutively recruited into this study. Materials and Methods: Blood pressure (mmHg), body mass index (kg/m2), concentrations of plasma glucose (mmol/l), lipid profile (mmol/l), TAS (mmol/l), vitamins C (µmol/l), and E (µmol/l) were determined in all participants. Statistical Analysis Used: Statistical Package for Social Sciences (SPSS) version 11.0 was used for statistical analysis. Results: The mean plasma TAS (1.18 ± 0.27 mmol/l), vitamin C (26.59 ± 7.39 µmol/L) and vitamin E (15.33 ± 4.05 µmol/l) of T2DM patients were significantly lower (P=0.0001 for all) than those of controls (1.58 ± 0.28 mmol/l, 43.56 ± 6.86 µmol/l, 31.22 ± 6.20 µmol/l respectively). TAS had a positive correlation with vitamin E (r=0.588; P=0.013) but no correlation with vitamin C (r=−0.387; P=0.139) among diabetics. Conclusions: TAS, vitamin C and E levels are reduced in T2DM patients compared with those of controls.Keywords: Total antioxidant status, type 2 diabetes mellitus, vitamin C, vitamin ENigerian Journal of Clinical Practice • Jan-Mar 2012 • Vol 15 • Issue

Disturbance and stress - different meanings in ecological dynamics?

There is an increasing frequency of papers addressing disturbance and stress in ecology without clear delimitation of their meaning. Some authors use the terms disturbance and stress exclusively as impacts, while others use them for the entire process, including both causes and effects. In some studies, the disturbance is considered as a result of a temporary impact, which is positive for the ecosystem, while stress is a negative, debilitating impact. By developing and testing simple theoretical models, the authors propose to differentiate disturbance and stress by frequency. If the frequency of the event enables the variable to reach a dynamic equilibrium which might be exhibited without this event, then the event (plus its responses) is a disturbance for the system. If frequency prevents the variable’s return to similar pre-event dynamics and drives or shifts it to a new trajectory, then we are facing stress. The authors propose that changes triggered by the given stimuli can be evaluated on an absolute scale, therefore, direction of change of the variable must not be used to choose one term or the other, i.e. to choose between stress and disturbance

Food-Web Structure of Seagrass Communities across Different Spatial Scales and Human Impacts

Seagrass beds provide important habitat for a wide range of marine species but are threatened by multiple human impacts in coastal waters. Although seagrass communities have been well-studied in the field, a quantification of their food-web structure and functioning, and how these change across space and human impacts has been lacking. Motivated by extensive field surveys and literature information, we analyzed the structural features of food webs associated with Zostera marina across 16 study sites in 3 provinces in Atlantic Canada. Our goals were to (i) quantify differences in food-web structure across local and regional scales and human impacts, (ii) assess the robustness of seagrass webs to simulated species loss, and (iii) compare food-web structure in temperate Atlantic seagrass beds with those of other aquatic ecosystems. We constructed individual food webs for each study site and cumulative webs for each province and the entire region based on presence/absence of species, and calculated 16 structural properties for each web. Our results indicate that food-web structure was similar among low impact sites across regions. With increasing human impacts associated with eutrophication, however, food-web structure show evidence of degradation as indicated by fewer trophic groups, lower maximum trophic level of the highest top predator, fewer trophic links connecting top to basal species, higher fractions of herbivores and intermediate consumers, and higher number of prey per species. These structural changes translate into functional changes with impacted sites being less robust to simulated species loss. Temperate Atlantic seagrass webs are similar to a tropical seagrass web, yet differed from other aquatic webs, suggesting consistent food-web characteristics across seagrass ecosystems in different regions. Our study illustrates that food-web structure and functioning of seagrass habitats change with human impacts and that the spatial scale of food-web analysis is critical for determining results

Seasonality constraints to livestock grazing intensity

Increasing food production is essential to meet the future food demand of a growing world population. In the light of pressing sustainability challenges like climate change and the importance of the global livestock system for food security as well as GHG emissions, finding ways to increasing food production sustainably and without increasing competition for food crops is essential. Yet, many unknowns relate to livestock grazing, in particular grazing intensity, an essential variable to assess the sustainability of livestock systems. Here we explore ecological limits to grazing intensity (GI; i.e., the fraction of Net Primary Production consumed by grazing animals) by analysing the role of seasonality in natural grasslands. We estimate seasonal limitations to GI by combining monthly Net Primary Production data and a map of global livestock distribution with assumptions on the length of non-favourable periods that can be bridged by livestock (e.g., by browsing dead standing biomass, storage systems or biomass conservation). This allows us to derive a seasonality-limited potential GI, which we compare with the GI prevailing in 2000. We find that GI in 2000 lies below its potential on 39% of the total global natural grasslands, which has a potential for increasing biomass extraction of up to 181 MtC/yr. In contrast, on 61% of the area GI exceeds the potential, made possible by management. Mobilizing this potential could increase milk production by 5%, meat production by 4%, or contribute to free up to 2.8 Mio km² of grassland area at the global scale if the numerous socio-ecological constraints can be overcome. We discuss socio-ecological trade-offs, which may reduce the estimated potential considerably and require the establishment of sound monitoring systems and an improved understanding of livestock system’s role in the Earth system

Ecology: a prerequisite for malaria elimination and eradication

* Existing front-line vector control measures, such as insecticide-treated nets and residual sprays, cannot break the transmission cycle of Plasmodium falciparum in the most intensely endemic parts of Africa and the Pacific * The goal of malaria eradication will require urgent strategic investment into understanding the ecology and evolution of the mosquito vectors that transmit malaria * Priority areas will include understanding aspects of the mosquito life cycle beyond the blood feeding processes which directly mediate malaria transmission * Global commitment to malaria eradication necessitates a corresponding long-term commitment to vector ecolog

Selecting Indicator Portfolios for Marine Species and Food Webs: A Puget Sound Case Study

Ecosystem-based management (EBM) has emerged as a promising approach for maintaining the benefits humans want and need from the ocean, yet concrete approaches for implementing EBM remain scarce. A key challenge lies in the development of indicators that can provide useful information on ecosystem status and trends, and assess progress towards management goals. In this paper, we describe a generalized framework for the methodical and transparent selection of ecosystem indicators. We apply the framework to the second largest estuary in the United States – Puget Sound, Washington – where one of the most advanced EBM processes is currently underway. Rather than introduce a new method, this paper integrates a variety of familiar approaches into one step-by-step approach that will lead to more consistent and reliable reporting on ecosystem condition. Importantly, we demonstrate how a framework linking indicators to policy goals, as well as a clearly defined indicator evaluation and scoring process, can result in a portfolio of useful and complementary indicators based on the needs of different users (e.g., policy makers and scientists). Although the set of indicators described in this paper is specific to marine species and food webs, we provide a general approach that could be applied to any set of management objectives or ecological system

Adipose energy stores, physical work, and the metabolic syndrome: lessons from hummingbirds

Hummingbirds and other nectar-feeding, migratory birds possess unusual adaptive traits that offer important lessons concerning obesity, diabetes and the metabolic syndrome. Hummingbirds consume a high sugar diet and have fasting glucose levels that would be severely hyperglycemic in humans, yet these nectar-fed birds recover most glucose that is filtered into the urine. Hummingbirds accumulate over 40% body fat shortly before migrations in the spring and autumn. Despite hyperglycemia and seasonally elevated body fat, the birds are not known to become diabetic in the sense of developing polyuria (glucosuria), polydipsia and polyphagia. The tiny (3–4 g) Ruby-throated hummingbird has among the highest mass-specific metabolic rates known, and loses most of its stored fat in 20 h by flying up to 600 miles across the Gulf of Mexico. During the breeding season, it becomes lean and maintains an extremely accurate energy balance. In addition, hummingbirds can quickly enter torpor and reduce resting metabolic rates by 10-fold. Thus, hummingbirds are wonderful examples of the adaptive nature of fat tissue, and may offer lessons concerning prevention of metabolic syndrome in humans