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Production of extracellular polysaccharides by halophilic Archaea and Bacteria has been widely reported and the members of the genus Halomonas have been identified as the most potential producers. In the present work, a novel exopolysaccharide (EPS-S6) produced by the extremely halotolerant newly isolated Halomonas elongata strain S6, was characterized. According to the HPAE-PAD results, EPS-S6 was mainly composed of glucosamine, mannose, rhamnose and glucose (1:0.9:0.7:0.3). EPS-S6 was highly negatively charged and its molecular weight was about 270 kDa. Studies on its functional properties showed that EPS-S6 had several potential features. It has noticeable antioxidant activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH•) inhibition and DNA protection, good ability to inhibit and to disrupt pathogenic biofilms, excellent flocculation of kaolin suspension and interesting emulsifying properties at acidic, neutral and basic pH. Therefore, EPS-S6 could have potential biotechnological concern in several fields such as in food, cosmetic and environmental industries.

The production and characterization of a bioflocculant, MBF-6, by Klebsiella pneumoniae was investigated. Optimum culture conditions for bioflocculant production were an initial medium pH of 7, an incubation temperature of 30 °C, and an inoculum size of 1 % (v/v) of cell density 1.0 × 108 cfu/mL. The carbon, nitrogen, and cation sources for optimum bioflocculant production were glucose, peptone, and ZnCl2. The bioflocculant mainly consisted of protein (3.4 %) and sugar (95.1 %). Fourier transform infrared (FTIR) spectrum revealed the presence of carboxyl and hydroxyl groups while the thermogravimetric analysis (TGA) showed a degradation temperature (T d) of 81.4 °C. MBF-6 had a good flocculating rate in kaolin suspension without cation addition and was stable over a wide range of pH and temperature. Investigation on the flocculation efficacy of the characterized MBF-6 for wastewater treatment of dairy, woolen, brewery, and sugar industries suggested it to be effective.

We present the results of a collaborative study for the establishment of a replacement International Standard (IS) for diphtheria toxoid for use in flocculation test and its calibration in Lf units. Calibration was performed using Ramon flocculation method, standardized using the 2nd IS. The candidate standard was assigned a unitage of 1870 Lf/ampoule based on results from 25 laboratories in 15 different countries and was established as the 3rd IS for diphtheria toxoid for use in flocculation test by the WHO Expert Committee on Biological Standardization (ECBS) in October 2015. The study also assessed the use of alternative methods for measuring Lf. Participants were asked to determine the Lf value of the candidate standard using an Enzyme Linked Immunosorbent Assay (ELISA) established at NIBSC, or other suitable in-house method. 10 laboratories performed ELISA according to the NIBSC protocol, 1 laboratory performed flocculation using laser-light scattering according to an in-house protocol, and 1 laboratory performed another in-house ELISA. Results suggest these methods may provide suitable alternatives to the Ramon flocculation test, subject to validation, and that the new standard could act as a suitable reference preparation in these methods.

Guar gum was grafted with polymethylmethacrylate (PMMA) by microwave initiated method. The synthesis was optimized for highest percentage grafting, by varying the microwave irradiation time and monomer (methyl methacrylate) concentration. The various grades of grafted product (GG-g-PMMA) were characterized through standard physicochemical characterization techniques (intrinsic viscosity measurement, elemental analysis, FTIR spectroscopy & SEM morphology study). Further, flocculation efficacy of this grafted polysaccharide was studied by standard ‘Jar test’ procedure in 0.5% kaolin suspension, to assess its application as flocculating agent for wastewater treatment and mineral ore beneficiation. Correlation between percentage grafting and intrinsic viscosity was also studied for the possibility of using it as a tool to control the intrinsic viscosity in the final product. This leads to the possibility of application of the grafted product as superior viscosifier than guar gum.

The activated sludge floc size distribution (FSD) is investigated by using different measurement techniques in order to gain insight in FSD assessment as well as to detect the strengths and limitations of each technique. A second objective was to determine the experimental conditions that allow a representative and accurate measurement of activated sludge floc size distributions. Laser diffraction, Time Of Transition (TOT) and Dynamic Image Analysis (DIA) devices were connected in series. The sample dilution liquid, the dilution factor and hydraulic flow conditions avoiding flocculation proved to be important. All methods had certain advantages and limitations. The MastersizerS has a broader dynamic size range and provides accurate results at high concentrations. However, it suffers from an imprecise evaluation of small size flocs and is susceptible to particle shape effects. TOT suffers less from size overestimation for non-spherical particles. However, care should be taken with the settings of the transparency check. Being primarily a counting technique, DIA suffers from a limited size detection range but is an excellent technique for process visualization. All evaluated techniques turned out to be reliable methods to quantify the floc size distribution. Selection of a certain method depends on the purpose of the measurement.

Tetanus toxoid is a vital primary reference material used for standardization of assays required to establish the antigenic purity of tetanus toxoid for vaccine production. Several formulations were assessed and ampouled fills of each formulation lyophilised. The relative Lf content determined by Ramon flocculation, SRD, and ELISA assays was measured. The stability of the tetanus toxoid activity in each formulation was assessed by accelerated degradation studies. Formulations containing glycine were not suitable in flocculation tests but both sorbitol and trehalose formulations were. The trehalose/sodium chloride formulation had a good appearance, showed good activity in all assays and maintained its activity best under stress conditions. This formulation has been applied to a large scale batch of ampoules prepared as a WHO candidate replacement standard, evaluated in a collaborative study and accepted as a replacement WHO IS for use in flocculation test (WHO ECBS, October 2007, ref no BS/07.2061). The stability of this formulation was also excellent for the large scale batch. The benefits of using thermal analysis and freeze drying microscopy coupled with small scale lyophilisation trials in order to screen formulations for the preparation of batches of biological reference materials are demonstrated.

A new semiempirical approach is presented for predicting air-to-water oxygen transfer rates in mixed tanks and gravity sewers, using methods adopted from mixing theory. First, a flocculation unit was used to impart selected mean velocity gradients (G) into a completely mixed tank, from which oxygen was first removed, and dissolved oxygen concentrations were measured with time. Regression analysis was used to fit the rate of oxygen transfer equation against G. The reaeration rate in completely mixed reactors was found to be proportional to G2 (R2 = 0.987). Subsequently, G was linked to headloss in sewers, and the equation was calibrated using a slope-adjustable, 27-m-long, gravity-flow, experimental sewer (internal diameter, D = 0.16 m). Here, the reaeration rate was proportional to G1 (R2 = 0.981). The equation was compared with existing oxygen transfer models and validated against experimental data from the literature, to which the overall mass transfer coefficient for oxygen, K(L)a, derived by the new approach, conformed well.

We described the ASiManager-AT digital flocculation reader to demonstrate concordance between visual and digital readings of the rapid plasma reagin test for detection of antibodies in the serum of patients with syphilis. A qualitative and quantitative rapid plasma reagin was performed on each serum samples giving a concordance of 98.6% and 99.7%, respectively, for reactives and 100% for nonreactives.

The diagnosis of syphilis is most frequently dependent on antibody detection with serological assays. Assays for both treponemal and non-treponemal antibodies are needed to provide a sensitive and specific diagnosis. For decades, a first screening has been done with non-treponemal assays, followed by treponemal. However, in recent years, following laboratory automation, the reverse sequence screening algorithms have been developed, using a treponemal assay as the initial screening test.To evaluate serological assays for treponemal and non-treponemal antibodies, to use in reverse algorithm screening of syphilis.Six treponemal assays (one IgM-specific assay), two non-treponemal assays and one novel dual point-of-care (POC) assay for serological diagnosis of syphilis were evaluated. Serum samples from Guinea-Bissau and Sweden were examined, as well as two performance panels and samples from blood donors. Sensitivity and specificity were calculated for each assay, using different assays as gold standard test.The Macro-Vue RPR Card test was the most sensitive non-treponemal test and the TrepSure Anti-Treponema EIA Screen and the SeroDia TP-PA were the most sensitive and specific treponemal assays. Among the automated assays, both the Liaison Treponema Screen and Architect Syphilis TP showed high sensitivity, however, the former had clearly higher specificity.In resourced settings, where the reverse sequence algorithm is preferred for screening, an automated treponemal immunoassay for initial screening subsequently followed by the TrepSure test or TP-PA assay as a second treponemal assay appear highly effective. Finally, a quantitative highly sensitive non-treponemal assay, e.g. the Macro-Vue RPR Card test, could then be used as a supplementary test to evaluate activity of the syphilis infection.

Aims: To isolate a new exopolysaccharide bioflocculant produced by the myxobacterium Sorangium cellulosum NUST06, and to characterize its chemical composition and expolysaccharide production relative to carbon source. Methods and Results: Exopolysaccharide levels and biomass production by S. cellulosum NUST06 were analysed relative to carbon source. Glucose in the medium at a level of 3 g l−1 completely inhibited cell growth and exopolysaccharide production, but low concentrations of glucose (1–2 g l−1) could stimulate cell utilization of starch. The chemical composition and flocculating activity of the NUST06 exopolysaccharide was investigated. The flocculant comprised 38·3% proteins and 58·5% carbohydrates, of which glucose, mannose and glucuronic acid were present at 51·3%, 39·2% and 10·5%, respectively. The flocculating activity of the NUST06 flocculant depended strongly on cations. Conclusions: It is feasible to produce an exopolysaccharide bioflocculant by the strain NUST06 in a mineral salts medium using starch as a carbon source. Significance and Impact of the Study: This strain may be advantageous for commercial bioflocculant production and may enrich existing knowledge of myxobacteria.

The antibacterial activity of a water-soluble chitosan derivative prepared by chemical modification to quaternary ammonium compound N,N,N-trimethylchitosan (TC) was investigated against four selected waterborne pathogens: Aeromonas hydrophila ATCC 35654, Yersinia enterocolitica ATCC 9610, Listeria monocytogenes ATCC 19111 and Escherichia coli O157:H7 ATCC 32150. An inactivation of 4 log CFU/ml of all waterborne pathogens was noted for the quaternized chitosan as compared with chitosan over a short contact time (30 min) and low dosage (4.5 ppm) at ambient temperature. A marked increase in glucose level, protein content and lactate dehydrogenase (LDH) activity was observed concurrently in the cell supernatant to be a major bactericidal mechanism. The results suggest that the TC derivative may be a promising commercial substitute for acid-soluble chitosan for rapid and effective disinfection of water.

This study introduces a novel optical monitoring method to image and characterize activated sludge flocs and to study the dependency of sludge settling properties on the floc structure. The novel method can easily analyse thousands of particles in a short timeframe using the developed image analysis program. The main advantage of this method is its applicability for in situ use because the only required pre-treatment is sample dilution. This study tested real process samples from activated sludge plants treating wastewater from a pulp mill. The sludge samples were collected in bulking and non-bulking situations, and the image analysis results were compared to the settling speed of the samples. The structure of the activated sludge flocs was clearly different in bulking sludge situations as characterized by more fragile and elongated flocs. Additionally, excessive amounts of filamentous bacteria hold the flocs apart, hindering sludge settling. These results show that this method is suitable for studying and optimizing activated sludge processes.

MIG1, encoding a C2H2 zinc-finger repressor protein involved in carbon catabolite repression, was found to play a role in non-sexual flocculation of Saccharomyces cerevisiae. Disruption of MIG1 in a flocculent mutant strain of NCYC 227, resulted in a non-flocculent phenotype. Expression of MIG1 on a 2 mu pRS426 vector in a non-flocculent strain, YM 4134, caused flocculation; MIG1 on a high-copy-number LEU2-d plasmid caused intense flocculation in the same strain. Mutations in the SSN6 and TUP1 genes confer a flocculent phenotype in non-flocculent strains of S. cerevisiae, and it has been shown that Mig1 can tether the Ssn6p-Tup1p complex to the regulatory regions of glucose-repressible genes. Mutations in tup1 in a MIG1 background caused flocculation while double mutants of TUP1 and MIG1 did not flocculate. Based on these results, a model for the role of MIG1 in flocculation gene regulation is proposed.

After extraction from whole cells, and purification by gel filtration, the chemical composition and molecular mass estimation of the cell-wall phosphopeptidomannan (PPM) showed no significant difference respectively between flocculent, weakly, very weakly and non-flocculent Kluyveromyces lactis yeast strains. However, when PPMs were tested as ligands of a lectin, extracted from the flocculent strain, the PPM isolated from the flocculent and weakly flocculent strain were recognized to a higher degree than those isolated from the non and very weakly flocculent strains. Acetolysis of PPM extracted from the four strains produced five oligosaccharide fractions corresponding to mono-, di-, tri-, penta-and hexa-saccharides. The flocculent strain was characterised by a high content of di-and penta-saccharides. The 1H NMR analysis of the oligosaccharides demonstrated that the flocculent strain contained equivalent levels of the two mannobioses: Man(alpha 1--2)Man and Man(alpha 1--3)Man and of the two mannotrioses Man(alpha 1--2)Man(alpha 1--2)Man and Man(alpha 1--3)Man(alpha 1--2)Man. In contrast, the non-flocculent and the very weakly flocculent strains contained a single type of mannobiose Man(alpha 1--2)Man and one type of mannotriose Man(alpha 1--2)Man(alpha 1--2)Man.

This paper reports a chemico-enzymatic synthesis of beta-CD derivatives. The recognition properties of these derivatives were tested using flocculating yeast and isolated lectins. It was observed that the substitution of beta-cyclodextrins with galactose end arms induces the better recognition by a cell-linked galactose-specific lectin. The physicochemical effects of the beta-CD derivatives on membranes were estimated using red blood cells and the effects on the viability of yeast and human rectal tumor cells were appreciated by measuring the mitochondrial deshydrogenase activity. The substitutions of the beta-CD ring by sugar antennae decrease the negative physicochemical effects of the beta-CD, ie their hemolytic properties. However, these substitutions induce significant modifications of the biological properties of the molecules, particularly the cytotoxicity and the growth of eukaryotic cells.

We report a glycoanalysis method in which lectins are used to probe the glycans of therapeutic glycoproteins that are adsorbed on gold nanoparticles. A model mannose-presenting glycoprotein, ribonuclease B (RNase B), and the therapeutic monoclonal antibody (mAb) rituximab, were found to adsorb spontaneously and non-specifically to bare gold nanoparticles such that glycans were accessible for lectin binding. Addition of a multivalent binding lectin, such as concanavalin A (Con A), to a solution of the modified gold nanoparticles resulted in cross-linking of the nanoparticles. This phenomenon was evidenced within 1 min by a change in the hydrodynamic diameter, D(H), measured by dynamic light scattering (DLS) and a shift and increase in absorbance of the plasmon resonance band of the gold nanoparticles. By combining the sugar-binding specificity and the cross-linking capabilities of lectins, the non-specific adsorption of glycoproteins to gold surfaces, and the unique optical reporting properties of gold nanoparticles, a glycosylation pattern of rituximab could be generated. This assay provides advantages over currently used glycoanalysis methods in terms of short analysis time, simplicity of the conjugation method, convenience of simple spectroscopic detection, and feasibility of providing glycan characterization of the protein drug product by using a variety of binding lectins.

This paper reports a novel microwave initiated method for synthesis of polyacrylamide grafted Psyllium (Psy-g-PAM). Psyllium was modified through grafting of polyacrylamide (PAM) chains on it using microwave radiations only, in absence of any other free radical initiator. The grafting was confirmed by intrinsic viscosity study and characterization techniques like FTIR spectroscopy, elemental analysis (C, H, N, O and S) and SEM morphology study. Further, the flocculation efficacy of the synthesized graft copolymers was studied in kaolin and coal fine suspension through standard ‘Jar test’ procedure.

The effects of chitosan addition on treatment of palm oil mill effluent were investigated using two lab-scale upflow anaerobic sludge bed (UASB) reactors: (1) with chitosan addition at the dosage of 2 mg chitosan per g volatile suspended solids on the first day of the operation (R1), (2) without chitosan addition (the control, R2). The reactors were inoculated with mesophilic anaerobic sludge which was acclimatized to a thermophilic condition with a stepwise temperature increase of 5 °C from 37 to 57 °C. The OLR ranged from 2.23 to 9.47 kg COD m −3 day −1 . The difference in biogas production rate increased from non-significant to 18% different. The effluent volatile suspended solids of R1 was 65 mg l −1 lower than that of R2 on Day 123. 16S rRNA targeted denaturing gradient gel electrophoresis (DGGE) fingerprints of microbial community indicated that some methanogens in the genus Methanosaeta can be detected in R1 but not in R2.

Twenty patients with eclampsia were studied for the presence of anticardiolipin antibodies by the standard microflocculation test (quantitative) used in the VDRL. Four out of 20 patients (20%) were positive for anticardiolipin antibodies. Anticardiolipin antibodies which are antiphospholipid antibodies by decreasing the prostacyclin production may damage the vascular endothelium and cause thrombosis in the vessels. Hence, the presence of anticardiolipin antibody in eclampsia may have association with antiphospholipid antibody syndrome described by Harris et al. (Lancet ii: 1211, 1983) and its central nervous system sequelae.

The Lf-unit, which is used in the control of diphtheria and tetanus toxoid production and in some countries also to follow immunization of horses for production of antitoxins, has hitherto been defined by means of antitoxin preparations. A diphtheria toxoid and a tetanus toxoid preparation, both freeze-dried, were examined in an international collaborative study for their suitability to serve as reference reagents in the flocculation tests and for defining the Lf-units. It was shown that flocculation tests using the reference toxoids are very reproducible and reliable and the WHO Expert Committee on Biological Standardization established: the toxoid called DIFT as the International Reference Reagent of Diphtheria Toxoid for Flocculation Test with a defined content of 900 Lf-units of diphtheria toxoid per ampoule; and the toxoid called TEFT as the International Reference Reagent of Tetanus Toxoid for Flocculation Test with a defined content of 1000 Lf-units of diphtheria toxoid per ampoule.

Internationally accepted designations of antigen content for toxoid vaccines are provided by the WHO in Lf (limes flocculationis) units, based on the formation of antigen-antibody complexes. The current assay method for Lf determination involves observation of the complexes by eye, making the development of a more objective system highly desirable. Here we report a novel detection system using a laser light-scattering platelet aggregometer. The system was highly reproducible and more objective than the current method. Only three sets of duplicate data were sufficient for statistically significant determination of toxoid Lf by parabolic regression.

Aims: To examine the role of the nutrients on the onset of flocculation in an ale-brewing strain, Saccharomyces cerevisiae NCYC 1195. Methods and Results: Flocculation was evaluated using the method of Soares, E.V. and Vroman, A. [Journal of Applied Microbiology (2003) 95, 325]. For cells grown in chemically defined medium (yeast nitrogen base with glucose) or in rich medium (containing yeast extract, peptone and fermentable sugars: fructose or maltose), the onset of flocculation occurred after the end of exponential respiro-fermentative phase of growth being coincident with the attainment of the lower level of carbon source in the culture medium. Cells, in exponential respiro-fermentative phase of growth, transferred to a glucose-containing medium without nitrogen source, developed a flocculent phenotype, while these carbon source starved cells, in the presence of all other nutrients that support growth, did not flocculate. In addition, cells in exponential phase of growth, under catabolite repression, when transferred to a medium containing 0·2% (w/v) of fermentable sugar (fructose or maltose) or 2% (v/v) ethanol, showed a rapid triggering of flocculation, while when incubated in 2% (v/v) glycerol did not develop a flocculent phenotype. Conclusions: The onset of flocculation occurs when a low sugar and/or nitrogen concentration is reached in culture media. The triggering of flocculation is an energetic dependent process influenced by the carbon source metabolism. The presence of external nitrogen source is not necessary for developing a flocculent phenotype. Significance and Impact of the Study: This work contributes to the elucidation of the role of nutrients on the onset of flocculation in NewFlo phenotype yeast strains. This information might be useful to the brewing industry, in the control of yeast flocculation, as the time when the onset of flocculation occurs can determine the fermentation performance and the beer quality.

Ethanol-soluble, but saline-insoluble antigens were prepared as saline suspensions and studied in double diffusion reactions in a soft agarose gel. Positive reactions were observed with syphilis and SLE sera tested against the Kahn antigen as well as against commercial cardiolipin reagents. Also, ethanol-soluble brain antigen was studied for organ-specific reactions with rabbit immune sera. It was shown that double diffusion in gel can be employed as an analytical procedure for studies on reactions of saline suspensions of ethanol-soluble antigens.

Two methods, centrifugation and flocculation, were evaluated to determine their efficiencies of recovery of Toxoplasma gondii oocysts from contaminated water samples. Demineralized and tap water replicates were inoculated with high numbers of sporulated or unsporulated T. gondii oocysts (1 × 10 5 and 1 × 10 4 oocysts). The strain, age, and concentration of the seeded oocysts were recorded. Oocysts were recovered either by centrifugation of the contaminated samples at various g values or by flocculation with two coagulants, Fe 2 (SO 4 ) 3 and Al 2 (SO 4 ) 3 . The recovery rates were determined with the final pellets by phase-contrast microscopy. Sporulated oocysts were recovered more effectively by flocculation with Al 2 (SO 4 ) 3 (96.5% ± 21.7%) than by flocculation with Fe 2 (SO 4 ) 3 (93.1% ± 8.1%) or by centrifugation at 2,073 × g (82.5% ± 6.8%). For the unsporulated oocysts, flocculation with Fe 2 (SO 4 ) 3 was more successful (100.3% ± 26.9%) than flocculation with Al 2 (SO 4 ) 3 (90.4% ± 19.1%) or centrifugation at 2,565 × g (97.2% ± 12.5%). The infectivity of the sporulated oocysts recovered by centrifugation was confirmed by seroconversion of all inoculated mice 77 days postinfection. These data suggest that sporulated Toxoplasma oocysts purified by methods commonly used for waterborne pathogens retain their infectivity after mechanical treatment and are able to induce infections in mammals. This is the first step in developing a systematic approach for the detection of Toxoplasma oocysts in water.

A comparative investigation was conducted of several methods for measuring the activity of the diphterial antitoxin in the preparation of allogenic antidiphterial immunoglobulin. The results of the studies made allow recommending the flocculation reaction and statistical method for use at blood transfusion stations in Ukraine when manufacturing the antidiphterial immunoglobulin, due to their informative, economic value and because they can easily be performed.

In studies of yeast flocculation it has been found that low concentrations of vanadium contained in sodium orthovanadate do not affect the growth and the cell-cell adhesion of the yeast Kluyveromyces bulgaricus, whereas high concentrations delay the growth of the yeasts and strongly inhibit flocculation. Moreover, higher sensitivity to Hygromycin B and calcofluor white was taken to imply altered cell wall integrity which is supported by compositional analysis of the extracted phosphopeptidomannans. Yeasts grown on sodium orthovanadate show a decrease in the percentage of phosphopeptidomannans and their compositions. It is proposed that the vanadium contained in sodium orthovanadate has a similar conformation to phosphorus and competes with phosphorus in phosphorylated compounds. The decrease of carbohydrate components and phosphorus linking to phosphopeptidomannans detected may alter their structure and modify ligand binding properties.

Rapid and definite assessment of the effect that a specific biocide has on a specific case of filamentous bulking sludge is a much-needed tool in activated sludge wastewater treatment. The Live/Dead stain (LIVE/DEAD BacLight) distinguishing "living" and "non-living" cells, a nitrifying activity (NA) test and the oxygen uptake rate (OUR) measurement were examined for their appropriateness to predict the effects of chlorine on filamentous bulking sludges. The study showed the live/dead stain to be relevant for revealing the specific effect of chlorine on the filamentous bacteria of a bulking sludge. However, using live/dead stain alone for the determination of the appropriate chlorine dose against bulking may lead to an underestimation of the damage caused by chlorine to the useful microorganisms in the flocs. Indeed, using the live/dead stain, it was not easy to distinguish dead cells caused by chlorination from those originally present in the flocs The NA test was the most sensitive in detecting damage caused by chlorine to the floc-forming microorganisms. Therefore, for a safer determination of the chlorine dose effective against bulking and protective of the microbial activity of the sludge, the results of this study suggest coupling of the live/dead stain with the NA test and/or the OUR test.

Klebsiella pneumoniae H12 produced a newly identified extracellular polysaccharide in an ethanol medium with a yield of 3.0 g/l. The molar composition of the polysaccharide was 56.04% galactose, 25.92% glucose, 10.92% galacturonic acid, 3.71% mannose, and 3.37% glucuronic acid. The addition of 0.5%-1.5% NaCl increased production. The polysaccharide flocculated with kaolin clay in suspension at the concentration of 1 ppm in a 300-ppm solution of CaCl2. Almost all bacterial species cells aggregated in the polysaccharide solution. The ability to flocculate with kaolin clay changed with the pH and with the concentrations of coexisting cation and anion species. The polysaccharide flocculant may participate in in vivo bacterial aggregation or adherence to host organisms.

An enzyme-linked immunosorbent assay (ELISA) for trichinosis using a Melcher's antigen was developed for the detection of IgG antibodies in 41 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences. ELISA- IgG was compared with a precipitin test (PT), a bentonite floculation test (BFT) and an indirect hemagglutination test (IHAT). The cut-off value was determined using serum samples from 67 apparently healthy persons employing two serum dilutions (1:100 and 1:500) with three standard deviations (SD). The sensitivity of ELISA- IgG was 97.6% and 95.2% using serum dilutions of 1:100 and 1:500 respectively, whereas the values for the other tests were: PT (92.7%), BFT (63.4%) and IHAT(85.4%). According to MacNemar test, ELISA-IgG did not present statistical significance (p0.05) compared with PT and IHAT, whereas all of them were different compared with BHT (p0.01). In order to find out the specificity of ELISA-IgG, additional 124 serum samples from individuals with other parasitoses, such as cysticercosis (31), fascioliasis (17), hydatidosis (51) and toxocariasis (25) were also tested. ELISA-IgG presented a specificity of 99.5% with both serum dilutions. The positive predictive values were 97.6 and 97.5%, whereas the negative one were 99.5 and 99.0% for 1:100 and 1:500 serum dilutions respectively. The use of ELISA-IgG and Melcher's antigen in the diagnosis of human trichinosis is discussed.

The paper describes an in-depth study of the parenteral fat emulsions, Intralipid 20% and Ivelip 20%. A large number of emulsion samples from separate containers and batches was sampled. The parameters measured were droplet size (both by photon correlation and laser diffraction), pH and zeta potential. These parameters were re-measured after the emulsions were subjected to a number of accelerated stability tests (freeze-thaw cycling, autoclaving and shaking). The results demonstrate that although the Intralipid is stable, it can show some variability between separate batches. The stability of Ivelip is high, and the variability between separate batches is extremely low.

The incidence of congenital syphilis has increased rapidly over the past few years. Most infected mothers and their newborns are asymptomatic at birth and diagnosis depends on serologic testing during pregnancy and at delivery. This study was initiated to compare maternal sera, cord blood, and neonatal sera for detecting presumptive congenital syphilis and to assess the role of maternal treatment (administration of penicillin to the mother at least 1 month before delivery) on the serologic results at the time of delivery. The serologic results from all live deliveries complicated by a positive maternal and/or neonatal test for syphilis during a 12-month period were compared using chi 2 analysis and multiple comparisons for proportions. Of 3306 livebirths, 73 (2.2%) were complicated by a positive maternal or neonatal serology. At delivery, the serologic test was positive in 68 (94%) of 72 maternal sera, 30 (50%) of 60 cord sera, and 43 (63%) of 68 neonatal sera. In the absence of maternal treatment, 95% of the maternal sera, 66% of the cord blood samples, and 86% of the neonatal sera were positive. If the mother had been treated, 94% of maternal sera, 36% of cord sera, and 39% of neonatal sera were positive. Cord blood and neonatal sera appear to be inferior to maternal sera for detecting prenatal exposure to syphilis. Cord serology is also inferior to neonatal serology at 2 to 3 days of age. The most effective way to identify newborns at risk for congenital syphilis is to obtain a maternal serologic diagnosis during pregnancy and to test maternal and neonatal sera at delivery.

In this paper the development of a surface plasmon resonance (SPR) immunosensor for syphilis screening is described. This immunosensor is based on the detection of antibodies in serum against the causative organism Treponema pallidum. In order to achieve selectivity a recombinant Treponema pallidum membrane protein A (TmpA) was used. This antigen can react with antibodies to T. pallidum, present in serum of syphilitic patients. Reproducible results have been obtained, using a ‘sandwich SPR’ method: binding of a sandwich antibody to the treponemal antibody after serum incubation was measured in real time while the binding was taking place. The SPR results obtained from ten blind-coded sera corresponded well with classical syphilis tests (Treponema pallidum haemagglutination assay (TPHA), fluorescent treponemal antibody-absorbed test (FTA-ABS), venereal diseases research laboratory flocculation test (VDRL) and TmpA-based enzyme-linked immunosorbent assay (TmpA-ELISA)). Preliminary experiments showed that direct measurement of serum (in the ‘one step SPRS) is not yet possible, probably as a result of non-uniformity of serum samples. The application of latex beads is considered to solve this problem.