RhizoFlowCell system reveals early effects of micropollutants on aquatic plant rhizosphere

In aquatic systems, one of the non-destructive ways to quantify toxicity of contaminants to plants is to monitor changes in root exudation patterns. In aquatic conditions, monitoring and quantifying such changes are currently challenging because of dilution of root exudates in water phase and lack of suitable instrumentation to measure them. Exposure to pollutants would not only change the plant exudation, but also affect the microbial communities that surround the root zone, thereby changing the metabolic profiles of the rhizosphere. This study aims at developing a device, the RhizoFlowCell, which can quantify metabolic response of plants, as well as changes in the microbial communities, to give an estimate of the stress to which the rhizosphere is exposed. The usefulness of RhizoFlowCell is demonstrated using naphthalene as a test pollutant. Results show that RhizoFlowCell system is useful in quantifying the dynamic metabolic response of aquatic rhizosphere to determine ecosystem health.

Ecogenomics reveals metals and land-use pressures on microbial communities in the waterways of a megacity

Networks of engineered waterways are critical in meeting the growing water demands in megacities. To capture and treat rainwater in an energy-efficient manner, approaches can be developed for such networks that use ecological services from microbial communities. Traditionally, engineered waterways were regarded as homogeneous systems with little responsiveness of ecological communities and ensuing processes. This study provides ecogenomics-derived key information to explain the complexity of urban aquatic ecosystems in well-managed watersheds with densely interspersed land-use patterns. Overall, sedimentary microbial communities had higher richness and evenness compared to the suspended communities in water phase. On the basis of PERMANOVA analysis, variation in structure and functions of microbial communities over space within same land-use type was not significant. In contrast, this difference was significant between different land-use types, which had similar chemical profiles. Of the 36 environmental parameters from spatial analysis, only three metals, namely potassium, copper and aluminum significantly explained between 7% and 11% of the variation in taxa and functions, based on distance-based linear models (DistLM). The ecogenomics approach adopted here allows the identification of key drivers of microbial communities and their functions at watershed-scale. These findings can be used to enhance microbial services, which are critical to develop ecologically friendly waterways in rapidly urbanizing environments.

Combination of synchrotron radiation-based Fourier transforms infrared microspectroscopy and confocal laser scanning microscopy to understand spatial heterogeneity in aquatic multispecies biofilms

Understanding the spatial heterogeneity within environmental biofilms can provide an insight into compartmentalization of different functions in biofilm communities. We used a non-destructive and label-free method by combining Synchrotron Radiation-based Fourier Transform Infrared Microspectroscopy (SR-FTIR) with Confocal Laser Scanning Microscopy (CLSM) to distinguish the spatial chemical changes within multispecies biofilms grown from natural storm waters in flow cells. Among the different surfaces tested for biofilm growth and optimal imaging, mylar membranes were most suited and it enabled successful spatial infrared imaging of natural biofilms for obtaining reliable and interpretable FTIR spectra. Time series analysis of biofilm growth showed that influx of water during biofilm growth, results in significant changes in biofilm formation. Early biofilms showed active nutrient acquisition and desiccation tolerance mechanisms corresponding with accumulation of secreted proteins. Statistical approach used for the evaluation of chemical spectra allowed for clustering and classification of various regions of the biofilm. Microheterogeneity was observed in the polymeric components of the biofilm matrix, including cellulose, glycocalyx and dextran-like molecules. Fructan and glycan-rich regions were distinguishable and glycocalyx was abundant in the strongly adhering peripheral regions of biofilms. Inner core showed coexistence of oxygen dimers and ferrihydrite that will likely support growth of Fe (II)-oxidising bacteria. The combined SR-FTIR microspectroscopy and CSLM approach for complex natural biofilms described here will be useful both in understanding heterogeneity of matrix components and in correlating functions of juxtaposed microbial species in complex natural biofilms with physicochemical microenvironment to which they are exposed.

In situ removal of dissolved and suspended contaminants from a eutrophic pond using hybrid sand-filter

In this study, in situ hybrid sand filters were designed to remove dissolved and suspended contaminants from eutrophic pond. Currently, there are no attempts made to eradicate dissolved as well as suspended contaminants from eutrophic water system in a single step. Monitoring studies revealed that examined pond contain high chlorophyll-a content (101.8 μg L(-1)), turbidity (39.5 NTU) and total dissolved solids concentration (0.04 g L(-1)). Samples were further exposed to extensive water quality analysis, which include examining physicochemical parameters (pH, conductivity, total dissolved solids, salinity, turbidity and chlorophyll-a), metals (Na, K, Ca, Mg, Al, Fe, Cu, Cd, Pb, Zn, Cr, and Ni) and anions (NO3, NO2, PO4, SO4, Cl, F and Br). To tackle pollutants, filtration system was designed to comprise of several components including fine sand, coarse sand/sorbent mix and gravel from top to bottom loaded in fiberglass tanks. All the filters (activated carbon, Sargassum and zeolite) completely removed algal biomass and showed potential to decrease pH during entire operational period of 20 h at 120 L h(-1). To examine the efficiency of filters in adverse conditions, the pond water was spiked with heavy metals (Cu, Cd, Pb, Zn, Cr, and Ni). Of the different filter systems, Sargassum-loaded filter performed exceedingly well with concentrations of heavy metals never exceeded the Environmental protection agency regulations for freshwater limits during total operational period. The total uptake capacities at the end of the fifth event were 24.9, 20.5, 0.58, 5.2, 0.091 and 2.8 mg/kg for Cr, Ni, Cu, Zn, Cd and Pb, respectively.

A bacterial quercetin oxidoreductase QuoA-mediated perturbation in the phenylpropanoid metabolic network increases lignification with a concomitant decrease in phenolamides in Arabidopsis

Metabolic perturbations by a gain-of-function approach provide a means to alter steady states of metabolites and query network properties, while keeping enzyme complexes intact. A combination of genetic and targeted metabolomics approach was used to understand the network properties of phenylpropanoid secondary metabolism pathways. A novel quercetin oxidoreductase, QuoA, from Pseudomonas putida, which converts quercetin to naringenin, thus effectively reversing the biosynthesis of quercetin through a de novo pathway, was expressed in Arabidopsis thaliana. QuoA transgenic lines selected for low, medium, and high expression levels of QuoA RNA had corresponding levels of QuoA activity and hypocotyl coloration resulting from increased anthocyanin accumulation. Stems of all three QuoA lines had increased tensile strength resulting from increased lignification. Sixteen metabolic intermediates from anthocyanin, lignin, and shikimate pathways had increased accumulation, of which 11 paralleled QuoA expression levels in the transgenic lines. The concomitant upregulation of the above pathways was explained by a significant downregulation of the phenolamide pathway and its precursor, spermidine. In a tt6 mutant line, lignifications as well as levels of the lignin pathway metabolites were much lower than those of QuoA transgenic lines. Unlike QuoA lines, phenolamides and spermidine were not affected in the tt6 line. Taken together, these results suggest that phenolamide pathway plays a major role in directing metabolic intermediates into the lignin pathway. Metabolic perturbations were accompanied by downregulation of five genes associated with branch-point enzymes and upregulation of their corresponding products. These results suggest that gene-metabolite pairs are likely to be co-ordinately regulated at critical branch points. Thus, these perturbations by a gain-of-function approach have uncovered novel properties of the phenylpropanoid metabolic network.

Reduction of nutrient contaminants into shallow eutrophic waters through vegetated treatment beds

One of the most effective mitigative approaches to eutrophication is the reduction of nutrient loading into water bodies. Bioremediation presents an economically viable and ecologically sustainable technology to nutrient pollution control taking advantage of the remarkable ability of plants and their associated microbial community to assimilate and remove nutrients from the environment. In this study, four emergent macrophytes (Cyperus haspan, Pandanus amaryllifolius, Pontederia cordata and Thalia geniculata) and two floating plants (Hygroryza aristata and Pistia stratiotes) were deployed in bank-side treatment beds and comparatively assessed for their remediative capabilities for nutrient control. P. stratiotes exhibited the highest removal efficiency for both nitrate and phosphate among the six plant species studied. Emergent macrophytes, P. amaryllifolius, C. haspan and P. cordata, were also found to be highly effective in nutrient uptake exhibiting removal efficiencies up to 100%. With the exception of T. geniculata, depletion of nutrients as a result of plant uptake significantly impeded the natural colonization of algae invariably leading to improvements in water quality in terms of turbidity and pH. Suppression of algae proliferation by T. geniculata was not preceded by a reduction in nutrient concentrations suggesting that T. geniculata may be directly inhibiting algal growth through allelopathy.

Bacterial diversity on different surfaces in urban freshwater

Microbial loads in freshwater systems have important implications in biogeochemical cycling in urban environments. Immersed surfaces in freshwaters provide surfaces for bacterial attachment and growth. Microorganisms that adhere initially to these surfaces play a critical role in biofilm formation and sustenance. Currently, there is little understanding on the type of organisms that initially adhere to different surfaces in urban canals. In this study, water from an urban stormwater canal was employed to allow bacteria to attach to different surfaces in a flowcell apparatus and understand the differences and changes in bacterial community structure. Bacterial communities were highly diverse on different surfaces as indicated by Jaccard's indices of 0.14-0.56. Bacteria on aluminium were the most diverse and on Plexiglas the least. Bacterial communities were highly dynamic in the early attachment phase and it changed by 59% between 3 and 6 h on aluminium. Specificity of attachment to surfaces was observed for some bacteria. Judicious use of materials in urban aquatic environment would help mitigate microbial load in urban waters.

Serum tumour necrosis factor-alpha and soluble tumour necrosis factor receptors levels in patients with Guillain-Barre syndrome

OBJECTIVES

To estimate the serum concentrations of Tumour Necrosis Factor alpha (TNF-alpha) and soluble TNF receptors (s TNF-RI and TNF-RII) in patients with Guillain-Barre syndrome (GBS), before and after treatment.

MATERIAL AND METHODS

The serum TNF-alpha and the soluble TNF receptors concentrations were measured by a sandwich enzyme-linked immunosorbent assay (ELISA) in 47 patients with GBS before and after the treatment - IVI therapy (n=26); Plasma Exchange (n=21).

RESULTS

At the time of admission, the serum TNF-alpha concentrations were elevated (32.5-182.5 pg/ml) in 41/47 GBS patients (87.2%). Following the treatment (IVIG or PE), there was a significant decrease in the serum TNF-alpha concentrations (8.5-58.5 pg/ml) in these 41 GBS patients. The soluble TNF receptors, particularly sTNF-RII concentrations were significantly increased in GBS patients treated by IVIG therapy.

CONCLUSIONS

The results of this indicated that (a) Elevated serum concentrations of TNF-alpha showed a positive correlation with the disease severity in patients with GBS. (b) The decrease in the serum TNF-alpha and increase in the serum soluble TNF receptors, particularly sTNF-RII showed a positive correlation with the neurological recovery in GBB patients following treatment.

Intravenous immunoglobulin reduces serum tumor necrosis factor alpha in patients with Guillain-Barre syndrome

BACKGROUND

Tumor necrosis factor a TNF-alpha has a possible role in the pathogenesis of the Guillain-Barre syndrome (GBS).

AIMS

To study the effect of intravenous immunoglobulin (IVIg) on serum TNF-alpha concentrations in patients with GBS.

MATERIAL AND METHODS

The effect of IVIg on TNF-alpha was evaluated in 36 patients with GBS. Serum TNF-alpha concentration was measured by enzyme-linked immunosorbent assay (ELISA). The sera of 22 (61%) patients with GBS showed elevated concentrations of TNF-alpha (35-182 pg/ml) and these sera were individually incubated in vitro with IVIg (0.25 mg/ml) at 37 degrees C for 24 hours.

RESULTS

The serum TNF-alpha concentrations in the 22 GBS patients with elevated levels showed a steady decline (60.34-19.78 pg/ml) following incubation with IVIg. These 22 patients also received IVIg therapy, and serum TNF-alpha concentrations showed a significant decline (65.5-9.75 pg/ml) at the end of the therapy. At the time of discharge from the hospital, there was a positive correlation between neurological recovery and decline in TNF-alpha concentrations in these 22 GBS patients.

CONCLUSIONS

The results of this study indicate that elevated levels of TNF-alpha occur in a proportion of patients with GBS and in these patients elevated serum TNF-alpha levels decline with IVIg therapy.

Circulating tumour necrosis factor alpha & soluble TNF receptors in patients with Guillain-Barre syndrome

BACKGROUND & OBJECTIVES

Tumour necrosis factor-alpha (TNF-alpha) is regarded as one of the immune factors that can induce demyelination of peripheral nerves in patients with Guillian-Barre syndrome (GBS). This present study was undertaken to find out the role of TNF-alpha and soluble TNF receptors in the pathogenesis of GBS; and to study the effect of intravenous immunoglobulin (ivIg) therapy on the serum TNF-alpha and soluble TNF receptors in patients with GBS.

METHODS

Thirty six patients with GBS in progressive stages of motor weakness were included in this study. The serum TNF-alpha and soluble TNF receptors (TNF-RI, TNF-RII) were measured in the serum samples of these patients before and after ivIg therapy by a sandwich ELISA.

RESULTS

Of the 36 patients with GBS, 26 (72.2%) showed elevated serum TNF-alpha levels prior to ivIg therapy. Following a complete course of ivIg therapy there was a progressive decrease in the serum TNF-alpha concentrations in these 26 patients. On the other hand, the soluble TNF receptors, particularly TNF-RII showed an increase in the serum of GBS patients following ivIg therapy.

INTERPRETATION & CONCLUSION

The results indicate that ivIg reduces the serum TNF-alpha concentrations in the GBS patients having elevated levels prior to ivIg therapy. Elevated serum levels of soluble TNF receptors following ivIg therapy may play a protective role by inhibiting the demyelinating effect of TNF-alpha in the peripheral nerves of patients with GBS.

Immunocytochemical method for early laboratory diagnosis of tuberculous meningitis

A simple immunocytochemical method was standardized for the direct demonstration of mycobacterial antigen in cerebrospinal fluid (CSF) specimens of patients with tuberculous meningitis (TBM). CSF-cytospin smears were prepared from 22 patients with a clinical diagnosis of TBM and also from an equal number of patients with nontuberculous neurological diseases (disease control). Immunocytological demonstration of mycobacterial antigens in the cytoplasm of monocytoid cells was attempted, by using rabbit immunoglobulin G to Mycobacterium tuberculosis as the primary antibody. Of the 22 CSF-cytospin smears from TBM patients, 16 showed positive immunostaining, while all of the CSF-cytospin smears from the disease control showed negative immunostaining for mycobacterial antigen. The technical aspects of this immunocytological method for the demonstration of mycobacterial antigens are simple, rapid, and reproducible, as well as specific, and therefore can be applied for the early diagnosis of TBM, particularly in patients in whom bacteriological methods did not demonstrate the presence of M. tuberculosis in the CSF.

Serum tumor necrosis factor-alpha in Guillain-Barré syndrome and its relation to plasma exchange

BACKGROUND

To correlate the serum tumor necrosis factor-alpha (TNFalpha) concentrations before, during and following plasma exchange in patients with Guillain-Barré syndrome (GBS). In this prospective study, 21 GBS patients were selected. Patients in clinical stages III to V were subjected to plasma exchange. The control group included equal numbers of age-matched patients with other neurological diseases and healthy voluntary blood donors. A sandwich ELISA method was applied to estimate serum TNFalpha concentrations in test and control groups.

REVIEW SUMMARY

Twelve GBS patients had elevated serum TNFalpha levels that ranged between 74 and 182 pg/mL. All 12 GBS patients showed a steady decrease in the TNFalpha concentration following plasma exchange and also showed a positive correlation with neurological recovery.

CONCLUSIONS

We conclude that serum TNFalpha concentrations are elevated in 57.1% of GBS patients and TNFalpha level decreases following plasma exchange.

A comparative evaluation of dot immunobinding assay (Dot-Iba) and polymerase chain reaction (PCR) for the laboratory diagnosis of tuberculous meningitis

The results of a Dot immunobinding assay (Dot Iba) for the detection of mycobacterial antigen in the cerebrospinal fluid (CSF) of 45 patients with tuberculous meningitis (TBM) were compared with the results of a polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis. In eight patients with culture proven TBM, Dot-Iba gave positive results, while PCR yielded positive results only in six patients. The overall sensitivities of Dot-Iba and PCR in 37 patients with culture negative (probable) TBM were 75.67% and 40.5% respectively. Dot-Iba, in contrast to PCR is a rapid and relatively easier method. More importantly, Dot-Iba is suitable for the routine application for the laboratory diagnosis of TBM and therefore best suited to laboratories in the developing world.

A dot-immunobinding assay (dot-Iba) for rapid diagnosis of pulmonary tuberculosis

IgG antibody to Mycobacterium tuberculosis from the sera of patients with 'definite' pulmonary tuberculosis (PT) was isolated and coupled with Cyanogen bromide-Sepharose 4B. Using an immunoabsorbent affinity chromatography, 14 kDa antigen was recovered from the culture filtrates of M. tuberculosis. With this mycobacterial antigen, a dot immunobinding assay (Dot-Iba) was developed for the detection of specific antibody to M. tuberculosis in the sera of patients with PT and controls. The assay gave positive results in all the 12 sputum-smear positive [acid fast bacilli (AFB)] patients with PT and gave negative results in the 50 sera from control groups. The Dot-Iba as described in this study, is simple, rapid and specific for laboratory diagnosis of PT.

Significance of serum antibody to GD1b ganglioside in patients with Guillain-Barré syndrome

BACKGROUND & OBJECTIVES

The precise etiological factors in Guillain-Barré syndrome (GBS) are still unknown. However, humoral and cellular immune factors may have a role in the pathogenesis of GBS. The present study was undertaken to evaluate the clinical significance of circulating serum IgG antibody to GD1b ganglioside in patients with GBS.

METHODS

Serial samples of serum were collected from 18 patients with GBS undergoing plasma exchange (PE) during their hospital stay. Serum IgG antibody titers to GD1b, before, during as well as following PE were measured by an indirect enzyme-linked immunosorbent assay (ELISA).

RESULTS

In 10 of 18 patients with GBS the antibody to GD1b was present in high titers (1:640-1:5120) prior to PE and the antibody titers in these 10 patients decreased following PE. At the time of completion of the study, the anti GD1b antibody titers declined in relation to clinical recovery in 7 of 10 patients with GBS.

INTERPRETATION & CONCLUSION

The findings of the present study show that antibody to GD1b gangliosides may be one of the immunological factors in the pathogenesis of GBS and PE decreases the anti GD1b antibody titers in these patients.

Circumcision in children with penile block alone

Surgical procedures in children are usually performed with the patient under general anesthesia. For circumcision and additional dorsal penile nerve block is used for postoperative analgesia. We retrospectively evaluated dorsal penile nerve block as the only analgesic technique for the relief of intraoperative pain in children undergoing circumcision. For 6 months dorsal penile nerve block was performed in 454 children 3 to 11 years old (mean 8.15 +/- 2.08 years) as the sole preoperative anesthesia. All boys were considered to have had good preoperative analgesia. No major complications were reported. Block related hematoma was noted in 12 patients (2.6%) and mild local edema occurred in 83 (18.3%). There was no excessive bleeding and hemostasis was easily achieved. The overall average operating time was 7.2 +/- 2.6 minutes (range 6 to 25). General anesthesia was added in 13 patients, representing a dorsal penile nerve block failure rate of 2.9%. Four boys suffered from erratic pain, while no objective cause of failure was recorded in the remaining 9. Average patient age was 5.8 +/- 2.2 years (range 3 to 10) in the 13 boys and 8.2 +/- 2 years (range 3 to 11) in the remaining 441 patients (p < 0.001). Failure was more frequent in children 3 to 5 years old (15.5%) than in those older than 6 years (1.5%, p < 0.05). Average operating time was 20.7 +/- 2.8 minutes (range 15 to 25) in the 13 children and 6.8 +/- 1.1 minutes (range 6 to 15) in the remaining 441 (p < 0.001). During the recovery period, only children from the general anesthesia group suffered from nausea and vomiting (9), and pain, agitation and fear (6 boys 3 to 6 years old). Average recovery room time was 38.7 +/- 7.4 minutes (range 30 to 60) in children with dorsal penile nerve block alone and 95 +/- 9.8 minutes (range 85 to 120) in those with additional general anesthesia (p < 0.001). We conclude that dorsal penile nerve block alone provides good intraoperative analgesia for circumcision in children, particularly those older than 6 years.

Intravenous regional anesthesia with ketorolac-lidocaine for the management of sympathetically-mediated pain

This retrospective study was undertaken to determine the usefulness of intravenous regional anesthetic (IVRA) blocks containing ketorolac and lidocaine in the management of sympathetically-mediated pain, and to determine what factors, if any, predicted success with this technique. Sixty-one patients with reflex sympathetic dystrophy presenting to a university-affiliated teaching hospital's pain management center were evaluated. Patients underwent one or more treatments with IVRA blocks containing ketorolac and lidocaine. The duration of pain, site of extremity affected, pain symptomatology, duration of relief from the first IVRA block, absence of pain following a series of IVRA blocks and side-effects from the IVRA blocks were determined. Of the 61 patients, 16 had complete response (26 percent), 26 had a partial response (43 percent) and 19 had no response (31 percent) to the ketorolac-containing IVRA. The only symptom which predicted a failure with this therapy was allodynia. No patient had serious side effects from the IVRA block; dizziness following tourniquet release occurred in 41 percent (n = 25) of the patients. IVRA block containing ketorolac is a useful and minimally invasive technique for the management of patients with reflex sympathetic dystrophy.

Treatment of primary hypercholesterolaemia with simvastatin. New Zealand multicentre evaluation

OBJECTIVE

To assess the efficacy of simvastatin in a large patient cohort.

DESIGN

In an open multicentre study, after a four week placebo phase, patients were treated with simvastatin for 24 weeks; a subgroup continued therapy for a further 24 weeks. Efficacy of simvastatin (a) with prolonged use over three years, and (b) in combination with bezafibrate was assessed in an open single site study.

SETTING

Lipid or cardiology specialist hospital outpatient clinics.

PATIENTS

For the open multicentre study, 228 patients with primary hypercholesterolaemia (total cholesterol level greater than 6.5 mmol/L) were recruited, of whom 224 met entry criteria and completed the study. Forty-seven of these patients continued therapy for one year. In the open single site study, 22 patients (with low density lipoprotein [LDL] cholesterol levels greater than 4.3 mmol/L) participated in studies of long term use (n = 9) or of combined therapy (n = 13).

INTERVENTION

Therapy in the open multicentre study began with 10 mg of simvastatin per day, doubling to 20 mg after six weeks and then 40 mg after 12 weeks of therapy if total cholesterol levels persisted above 5.2 mmol/L. In the study of long term use, simvastatin (40 mg daily) was taken continuously over three years. In the study of combination therapy, bezafibrate (600 mg daily) was taken in addition to simvastatin (40 mg daily) for 10 months.

MAIN OUTCOME MEASURES

Plasma lipid and lipoprotein concentrations.

RESULTS

In the multicentre study, total plasma cholesterol levels were reduced by 32.8% from 9.11 +/- 1.84 (in mmol/L, mean +/- SD) to 6.12 +/- 1.25 (P less than 0.001), and LDL cholesterol levels by 41.4% from 6.90 +/- 1.92 to 4.04 +/- 0.31 (P less than 0.001). The effect of therapy was sustained in those patients continuing therapy to 48 weeks. The study of long term use found no significant attenuation of effect over three years of monotherapy. Combined simvastatin/bezafibrate therapy reduced the LDL cholesterol concentration by a further 19.9% (P less than 0.001) from levels achieved on simvastatin alone.

CONCLUSIONS

Simvastatin is an effective, well tolerated lipid lowering drug, without significant attenuation of effect with prolonged use. Simvastatin plus bezafibrate appears to be a potentially useful drug combination.

Repeated percutaneous internal jugular cannulation using flow directed Swan Ganz catheter

The use of flow directed Swan Ganz catheters has provided an additional dimension in improving patient care in the intensive care units. We undertook repeated Swan Ganz catheterization in 26 patients with congestive cardiac failure on 65 occasions to evaluate the effect of vasodilator drugs. The same internal jugular vein was used. No significant complications were noted.

Gingival hyperplasia associated with nifedipine therapy. Report of a case

A case of gingival hyperplasia associated with the administration of nifedipine is reported. Clinically and histologically, the tissue resembled that seen in hyperplasia induced by phenytoin (Dilantin). We believe this to be the first reported case of gingival hyperplasia associated with this drug.