Screening for chronic kidney disease and its risk factors in Oghara, Nigeria: a World Kidney Day 2014 report

Background: The risk factors associated with CKD such as hypertension, diabetes and obesity remain prevalent globally, resulting in a high prevalence of CKD especially in developing countries. Screening for CKD and its' risk factors is recommended for high-risk population. This study aimed to determine the prevalence and risk factors of CKD in a semiurban community in Nigeria.Methods: A cross-sectional survey was conducted in the teaching hospital premises at Oghara, after a world kidney day (WKD) health awareness campaign was undertaken in the community. A total of 135 subjects were interviewed and the following measurements were performed: blood pressure, body mass index, blood glucose, dipstick urinalysis, serum creatinine and estimation of glomerular filtration rate (GFR) using CKDEPI.Results: Mean age was 40 ± 13 years and 69.6% of participants were young. Male to female ratio was 1:4. The prevalence of proteinuria was 4.4% while 10.7% of all subjects had CKD (GFR <60ml/min). Although 11.1% of participants were known hypertensives only 6.7% had high blood pressure on screening. Other risk factors identified were Diabetes mellitus (10.3%), family of history of hypertension (14.1%), family of history of diabetes (9.6%), family of history CKD (1.5%) and obesity (11.9%). Proteinuria, diabetes and family history of hypertension were significantly associated with CKD.Conclusions: CKD and its risk factors are common in the population.Dipstick proteinuria remains a useful and significant indicator of CKD.Community screening for the risk factors of CKD in developing countries is realistic and should be encouraged as a public health priority

Grazing rates of diverse morphotypes of bacterivorous ciliates feeding on four allochthonous bacteria.

AIMS: The permanence in aquatic systems of allochthonous bacteria coming from sewage effluents is a risk for public health. This work aimed to analyse the elimination of the bacteria Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli and Klebsiella pneumoniae by a riverine ciliate community. METHODS AND RESULTS: The ciliates were characterized and identified on the basis of morphological and behavioural features and grouped in nine morphotypes. Differential grazing by each morphotype on the four allochthonous bacteria was carried out by adding fluorescently labelled bacteria to the water samples, and measuring their uptake along time. CONCLUSIONS: The nine morphotypes were present in all the samples but in different proportions, being the most abundant the small scuticociliates and hipotrichs. The smallest morphotypes showed grazing rates lower than 20 FLB ciliate(-1) h(-1), with a preference towards K. pneumoniae. The larger morphotypes showed in general the highest grazing rates, but the selectivity was hardly attributable to bacterial size or type of cell wall. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The elimination of allochthonous bacteria in an aquatic system may be highly different depending on the diversity of the ciliated protistan community in the system and on the nature of the bacterial prey.

Spatial distribution of protists in the presence of macroaggregates in a marine system.

The spatial distribution of marine protistan communities in the presence of organic macroaggregates, formed from natural seawater, was studied in several microcosm experiments. The presence of macroaggregates had two main effects. First, the size of the communities of bacteria, flagellates and ciliates increased, as these communities were three orders of magnitude higher in the aggregates than in the microcosm water. In addition, it brought the diversification on the niches accessible to planktonic microorganisms, as three phases were formed: water, aggregates and aggregate-water interphase. Some of the detected protistan taxa were only found in the water, and therefore they can be considered as truly free-swimming protists. Others quickly colonised the aggregates, and finally, some of them showed a preference for the aggregate-water interphase. We discuss this spatial structuring of the protistan community on the basis of their feeding strategies and structural and behavioural characteristics.

Ectoenzymatic Activity and Uptake of Monomers in Marine Bacterioplankton Described by a Biphasic Kinetic Model.

Abstract The kinetics of bacterial hydrolytic ectoenzymatic activity and the uptake of monomeric compounds were investigated in the Northwestern Mediterranean Sea. Aminopeptidase and alpha- and beta-glucosidase activities were analyzed by using fluorogenic substrates at 15-22 concentrations ranging from 1 nM to 500 µM. Radiolabeled glucose and a mixture of amino acids were chosen as representatives of monomeric compounds, and the bacterial uptake rates (assimilation plus respiration) were determined over a wide range of substrate concentrations (from 0.2 nM to 3 µM). We found biphasic kinetics both for hydrolytic enzymes and uptake systems: high affinity enzymes at low concentrations of substrates (Km values ranged from 48 nM to 2.7 µM for ectoenzymes and from 1.4 nM to 42 nM for uptake systems), and low affinity enzymes at high concentrations of substrates (Km values ranged from 18 µM to 142 µM for ectoenzymes and from 0.1 µM to 1.3 µM for uptake systems). Transition between high and low affinity enzymes was observed at 10 µM for aminopeptidase and from 1 µM to 25 µM for glucosidases, and it was more variable and less pronounced for the uptake of glucose (40 nM-0.28 µM) and amino acids (10 nM-0.16 µM). Results showed that the potential rates of hydrolysis and uptake are tightly coupled only if the high affinity hydrolytic ectoenzymes and the low affinity uptake systems are operating simultaneously.

Channeling of bacterioplanktonic production toward phagotrophic flagellates and ciliates under different seasonal conditions in a river.

The objective of this study was to analyze the flux of biomass through the communities of bacteria and phagotrophic protists in the cold and warm conditions occurring seasonally in Butrón River. Bacterial and heterotrophic protistan (flagellate and ciliate) abundance was determined by epifluorescence direct counts; protistan grazing on planktonic bacteria was measured from fluorescently labeled bacteria uptake rates; and the estimate of bacterial secondary production was obtained from [(3)H]thymidine incorporation rates. The abundance of bacterial, flagellate, and ciliate communities was similar during cold and warm situations. However, we observed that estimates of dynamic parameters, i.e., secondary bacterial production and protistan grazing, in both situations were noticeably different. In the warm situation, grazing rates of flagellates and ciliates (bacteria per protist per hour) were, respectively, 7 times and 18 times higher than those determined in the cold situation, and the grazing rates of the protistan communities (bacteria per protists present in 1 ml of water per hour) increased up to 5 times in the case of flagellates and 42 times in the case of ciliates. Estimates of bacterial secondary production were also higher during the warm situation, showing a ninefold increase. The percentage of bacterial production preyed upon by flagellates or ciliates was not significantly different between the two conditions. These results showed that in the different conditions of a system, the flux of biomass between the trophic levels may be quite different although this process may not be reflected in the abundance of each community of bacteria, flagellates, and ciliates.

Comparison of rates of flagellate bacterivory and bacterial production in a marine coastal system.

Protozoan predation on bacteria and bacterioplankton secondary production were simultaneously determined in La Salvaje Beach water during 1990. Protozoan grazing on bacterioplankton was measured from fluorescently labeled bacterium uptake rates; estimates of bacterial secondary production were obtained from [H]thymidine incorporation rates. Two different conversion factors were used to transform thymidine incorporation rates into bacterial production rates; both of them were specific for La Salvaje Beach and were calculated by using empirical and semitheoretical approaches. The average flagellate predation rate was 14.0 bacteria flagellate h; the average population predation rate was 7.35 x 10 bacteria liter h. The estimates of bacterial production differed greatly depending on the conversion factor used, and so did the percentages of bacterial production consumed by flagellated protozoa (4.6% when the empirical conversion factor for La Salvaje Beach was used and 113% when the semitheoretical conversion factor specific for this system was used). The ecological implications of each of these values are discussed.

Temporal variability of attached and free-living bacteria in coastal waters.

The temporal variability of the abundance and the incorporation of (3)H-thymidine and (14)C-glucose by attached and free-living bacteria, as well as their relation with environmental factors, were analyzed in a coastal marine ecosystem during a year. Both communities were quantitatively very different. Attached bacteria represented only 6.8% of the total bacterial abundance, whereas free-living bacteria represented 93.2%. The environmental factors most closely linked to the abundance and activity of free-living bacteria were temperature and the concentration of dissolved nutrients. Moreover, the free-living community showed similar temporal variations in abundance and in activity, with lower values in the cold months (from October to May). The attached community did not present the same pattern of variation as the free-living one. The abundance of the attached bacteria was mainly correlated to the concentration of particulate material, whereas their activity was correlated to temperature. We did not find a significant correlation between the abundance and the activity of the attached community. On the other hand, the activity per cell of the two communities did not present a clear temporal variation. Attached bacteria were more active than free-living ones in the incorporation of radiolabeled substrates on a per cell basis (five times more in the case of glucose incorporation and twice as active in thymidine incorporation). However, both communities showed similar specific growth rates. The results suggest that the two aquatic bacterial communities must not be considered as being independent of each other. There appears to be a dynamic equilibrium between the two communities, regulated by the concentrations of particulate matter and nutrients and by other environmental factors.

Bacterial production and growth rate estimation from [h]thymidine incorporation for attached and free-living bacteria in aquatic systems.

Production and specific growth rates of attached and free-living bacteria were estimated in an oligotrophic marine system, La Salvaje Beach, Vizcaya, Spain, and in a freshwater system having a higher nutrient concentration, Butron River, Vizcaya, Spain. Production was calculated from [methyl-H]thymidine incorporation by estimating specific conversion factors (cells or micrograms of C produced per mole of thymidine incorporated) for attached and free-living bacteria, respectively, in each system. Conversion factors were not statistically different between attached and free-living bacteria: 6.812 x 10 and 8.678 x 10 mug of C mol for free-living and attached bacteria in the freshwater system, and 1.276 x 10 and 1.354 x 10 mug of C mol for free-living and attached bacteria in the marine system. Therefore, use of a unique conversion factor for the mixed bacterial population is well founded. However, conversion factors were higher in the freshwater system than in the marine system. This could be due to the different trophic conditions of the two systems. Free-living bacteria contributed the most to production in the two systems (85% in the marine system and 67% in the freshwater system) because of their greater contribution to total biomass. Specific growth rates calculated from production data and biomass data were similar for attached and free-living bacteria.