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PubMed2004

The influence of settling time on the formation of aerobic granules.

Aerobic granular sludge, without the addition of carrier material, has only been reported in one suspended growth system, the Sequencing Batch Reactor (SBR) operated with short fill and settling periods. Recent studies have demonstrated that extracellular polysaccharides increased with the formation of aerobic granules, and that the shear force may stimulate production of these polysaccharides. In the study described herein, two SBRs were operated with the same shear force (air flow rate 275 L h(-1)) and two different settling times (2 and 10 min). Only the reactor with 2 min settling formed completely granular sludge, although granules were present in both reactors. Community analysis using 16S rRNA PCR products and DGGE showed that the communities diverged quickly after reactor start-up. For samples taken at steady-state, the granular population was more stable and less diverse than the flocculent reactor. EPS extraction of samples using cation exchange resin yielded similar values for aerobic granular sludge and previously reported anaerobic granules. While differences in the protein and TOC content between the flocculent and granular reactors increased appreciably as the sludge became more granular, the protein to polysaccharide ratio was relatively constant. The experiment confirmed previous theories that short settling times in SBRs select for granular sludge. The settling time results in granular sludge having a higher EPS protein content and a less diverse but more stable population.

Bacteria, Aerobic↗

PubMed2003

Coaggregation between Acinetobacter johnsonii S35 and Microbacterium esteraromaticum strains isolated from sewage activated sludge.

The extent and nature of intergeneric coaggregations among non-flocculating sludge bacteria were studied through examination of the coaggregation abilities of Acinetobacter johnsonii S35 with two other strains of non-flocculating sludge bacteria (Microbacterium esteraromaticum S38 and M. esteraromaticum S51). At first, the effect of electrolyte concentration as well as the addition of EDTA and proteases on coaggregation were studied. Changes in electrolyte concentration had little effect on the aggregation index (A.I.). However, the A.I. was reduced by 35-45% (addition of 2 mM EDTA) and 15-58% (addition of 0.2 mg/ml Actinase E) within 1 h depending upon the bacterial pair involved. Furthermore, the effect of pretreating either A. johnsonii S35 or its partners with Actinase E and periodate, respectively, was studied. The results indicate that these coaggregations involve a protein on the partner's surface that may interact with carbohydrate or a carbohydrate-containing moiety on the surface of A. johnsonii S35.

Journal Article↗

PubMed1992

Ranitidine improves postoperative suppression of antibody response to preoperative vaccination.

The effect of the histamine-2 receptor antagonist ranitidine (100 mg intravenously every 12 hours for 72 hours) on postoperative serum antibody responses to preoperative immunization with six limit of flocculation tetanus toxoid and six limit of flocculation diphtheria toxoid was assessed in a double-blind, placebo-controlled randomized study in 26 patients undergoing major abdominal surgery. The preoperative antitetanus antibody level was less than 0.1 IU/ml in all patients, and they were inoculated with both antigens 48 hours before surgery. Serum samples for analysis of antitetanus toxoid and antidiphtheria toxoid were drawn before skin incision and on postoperative days 1, 3, 5, 7, 10, 14, 21, and 28. Ranitidine significantly increased the postoperative antibody response to tetanus toxoid, (p less than 0.01) and insignificantly increased that to diphtheria toxoid vaccination (p less than 0.2) compared with placebo.

Adult↗

PubMed1976

The standardization of Cl. perfringens antigens and antisera.

The preparation of laboratory standard antitoxins against Cl. perfringens beta and epsilon toxins is described. These antitoxins are suitable for the quantitative determination of the corresponding antigens by means of the flocculation test. The flocculation test was, however, shown to be more suitable for determining the antigenic value of fresh toxoid rather than toxoid stored without neutralization of excess formalin. A maximal immunity response to alum-precipitated epsilon toxoid was obtained in sheep with two injections containing 90 Lf per dose. The interval between these injections may vary from 2 to 6 weeks. The serum-antibody titres after the primary and secondary injections or after a booster dose given before 12 months after the primary injection did not remain above the protective level in most of the sheep injected for longer than about 5 months. When a sound basic immunity is established the degree of protection following on a booster dose given 12 months later is complete for at least 12 months. An alum-precipitated vaccine containing 25 Lf epsilon toxoid per dose is adequate. The decline in the serum-antibody titre during the first year of vaccination could be eliminated by the use of the antigen in water-in-oil emulsion. Lambs from immune dams were protected for at least up to 13 weeks of age. A satisfactory level of circulating antitoxin against Cl. perfringens beta toxin could be produced in ewes by vaccinating them with APT containing 6.25 Lf beta toxoid per dose. The primary and secondary injections could be separated by 2, 3, 4 or 5 weeks without changing the end result. A booster dose given 2 months before parturition was satisfactory.

Animals↗

PubMed1991

Kluyveromyces bulgaricus yeast lectins. Isolation of two galactose-specific lectin forms from the yeast cell wall.

Incubation of galactose treated Kluyveromyces bulgaricus yeast cells in EDTA/phosphate-buffered saline led to an extract possessing hemagglutinating and yeast flocculating properties. Purification of this extract by affinity chromatography and gel filtration gave two lectin forms, Kb-CWL I and Kb-CWL II, with an apparent molecular mass of 38,000 and 150,000 Da, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that Kb-CWL I and Kb-CWL II were dimeric and octameric of a subunit of 18,900 Da. At high concentration, purified Kb-CWL I associated to give Kb-CWL II. This association seemed to be independent on pH. The two lectin forms were glycoproteins, the peptide counterpart was very rich in Lys, Glu, and Gly, and the carbohydrate part represented 1% of the whole molecule and was composed of Glc, Man, and Ara. The two lectin forms (KB-CWL I and Kb-CWL II) agglutinated human red blood cells and flocculated EDTA-treated K. bulgaricus yeast cells. The activity of both lectin forms required Ca2+ ions, while Sr2+ showed some competitive inhibition. Optimal activity was obtained within a pH range of 4-6.5 for both forms. Temperatures of 80-90 degrees C for 20 min, or proteolytic treatment reduced irreversibly the activity of Kb-CWL I and Kb-CWL II. The role of the cell wall phosphopeptidomannan as a ligand and a potential physiological receptor of these lectin forms was demonstrated.

Agglutination↗

PubMed1979

Hepatitis, cardiomyopathy and hemodynamics in furazolidone-induced round heart disease of turkeys.

Twenty-five large broad-breasted white turkeys were fed a 22% protein diet supplemented with 500 ppm furazolidone from day 1 to 3.5 weeks of age and the same diet supplemented with 700 ppm furazolidone until 9.5 weeks of age. Following the development of round heart disease as indicated by altered electrocardiograms the 25 turkeys were sacrificed. In the livers of turkeys with biventricular dilatation (72% of cases) there was bile duct hyperlasia, portal fibrosis and intracytoplasmic globules in the hepatocytes. Globules stained pink with hematoxylin-eosin, deep red with PAS and variable with Massons trichrome stains in paraffin-embedded liver sections. Clear intracytoplasmic vacuoles demonstrable in hepatocytes of PAS stained liver sections embedded in paraffin did not stain as lipid in frozen sections but did contain sparse flocculent material in 1 micrometer sections of liver embedded in epoxy resin and stained with toluidine blue. At the subcellular level, the intracytoplasmic globules in hepatocytes were surrounded by a single membrane, contained flocculent material and had enzymatic properties characteristic of lysosomes. Blood pressure, heart rate, dp/dt max, total plasma proteins and plasma trypsin inhibitory capacity of turkeys with round heart disease were lower than corresponding values for control turkeys. Control turkeys did not exhibit the characteristic gross or microscopic lesions of round heart disease.

Animals↗

PubMed1989

[Vibration-induced inactivation of insulin].

A case of diabetic ketoacidosis precipitated by employment of flocculated, and thus inactivated, insulin is presented. The flocculation is presumed to have been produced by vibrations which are presumed to make slow-action insulin form insoluble fibrils at room temperature. This mechanism is recognized in rapid-action insulin.

Adult↗

PubMedDate not supplied

[Removal of arsenic from water for human consumption in homes in rural communities in the Comarca Lagunera, Mexico].

This paper presents the results of an intradomiciliary procedure for arsenic removal from water, by means of flocculation with ferric sulphate. The reaction was carried out in a specifically designed tank with a manual agitator (reactor) installed in a vertical support. The salts to flocculate were handed in two small envelopes, whose contents were added independently, agitating the water and letting it settle for two to three hours. Water is decanted by opening a faucet connected to the inferior part of the recipient. Ten families of the states of Durango and Coahuila (the Comarca Lagunera) were selected. Samples of water were taken before and after the treatment. In 70 percent of these samples the arsenic removal was total, and in the remaining 30 percent the removal was superior to 93 percent. The arsenic removal of water in the domicile was very effective, for which it is suggested as a palliative method for those groups with higher levels of exposition.

Arsenic↗

PubMed1986

[Various Salmonella serotypes isolated at a sewage purification plant in a smaller city over a one-year period].

A one-year-study was carried out in the waste-water treatment plant of Plön (population equivalents 60,000), which has a mechanical and a biological purification and an additional chemical flocculation. Samples were taken at five different places in the plant and examined for Salmonella by use of membrane-filtration and MPN-method. 2,611 Salmonella-strains, representing 23 species, were isolated and serologically typed from samples taken at ten days. S. typhi-murium was found most frequently (Table 1, Fig. 1). The largest spectrum of different types was located in the activated sludge-basin and at the outlet of the chemical flocculation (Table 2). No correlation could be established between the qualitative findings and the Salmonella-counts or other parameter like temperatures. All the ten species that have been officially reported to cause salmonellosis in man were also isolated from the sewage (Table 5). Findings of other Salmonella-serotypes are attributed to unreported human infections and animals or other sources.

Germany, West↗

PubMed1983

Low residual diet and hydration improving double contrast examination of the colon.

Light food diet and low residual diet with hydration, both combined with Proctosal and Bisacodyl cleansing, were compared in 268 patients in the preparation of the colon for double contrast examination. Low residual diet with hydration resulted in significantly less residual fecal material, no flocculation of the barium coating and significantly denser mucosal coating. The examination had to be repeated more often (8.6%) after light food diet than after low residual diet with hydration (1.7%), but there was no statistically significant difference in the diagnostic accuracy. The hydration is important in avoiding patient discomforts and flocculation of the barium coating. Despite the use of laxatives, a strict diet restriction is needed to obtain consistently clean colon.

Adolescent↗

PubMed1983

Nephrocalcinosis in vitro.

In order to study the mechanism of dystrophic calcification, an anoxic incubation of rat renal cortex in a tissue culture medium was performed in vitro. Calcium and phosphate in the medium were adjusted to 1.6 and 1.2 mM/1 respectively. Calcification occurred in apposition to the inner surface of membranous cellular degradation products and associated with the flocculent densities within the degenerate organelles. The chemical nature of the flocculent density was not determined. In view of the known affinity of calcium for acidic phospholipids, particularly phosphatidyl serine (PS), which lines the inner surface of the plasma membrane, calcification along the inner surface of membrane was thought to be related to the presence of PS. Accumulation of calcium in mitochondria, which is presumably dependent upon residual substrate for energy production, appeared to cause calcification as well. Amorphous calcium phosphate in the form of spheroids, and possibly fine fibrils and granules, also appeared to play a role in calcification by their transformation into apatite. The seemingly simple phenomenon of tissue calcification is complex. Nephrocalcinosis in vitro is remarkably similar to the calcification in acute tubular necrosis in vivo, and is a convenient model with which to study the mechanism of calcification. It is concluded that the cellular degradation products are the initial loci of calcification and have a likely role in urolithiasis.

Animals↗

PubMed1983

Electron microscopic and cytochemical study of the cortical cytoplasm in the preovulatory human oocytes.

Important changes take place in the cortical cytoplasm of human oocytes in connection with their maturation. Contacts between granulosa cell processes and the oocyte are interrupted, the perivitelline space develops, invaded by oocyte long microvilli. Fine flocculent material is deposited in the perivitelline space. As for oocyte cell organelles, changes occur especially in the granular endoplasmic reticulum which, formerly creating a network of cisternae studded with a low number of ribosomes, eventually becomes disintegrated, splitting into individual smooth vesicles scattered together with mitochondria throughout the cytoplasm. The number of Golgi structures drops substantially. Cortical granules mature and become organized into a single layer beneath the cell membrane. Acid mucopolysaccharides, glycoproteins and proteins were demonstrated in their contents. In addition to the above cortical granules, morphologically distinct secretory vesicles are present in the cortical cytoplasm of human preovulatory oocytes. Their number increases markedly during the resumption of meiosis when they release their contents into the perivitelline space. Like the extracellular flocculent material deposited in the perivitelline space, also the secretory vesicles contain glycoproteins and proteins. The extrusion of this glycoprotein material into the perivitelline space coincides temporally with the loosening of microvilli, previously embedded in the zona pellucida material, and with the interruption of oocyte-follicular cells contacts.

Adult↗

PubMed1983

Eight types of endocrine cells in the abomasum of sheep.

In the ovine abomasum, 8 types of endocrine cells were classified at ultrastructural level. The gastric-type EC cells contained oval and pleomorphic granules with high electron density. The intestinal-type EC cells were filled with oval, irregular and highly dense granules. ECL cells contained irregular granules with high density and wide clear spaces. D cells were filled with round granules showing low to moderate density and finely granular matrix D1 cells contained round or oval granules with variable, low to moderate density and finely granular content. G cells showed round and oval granules with moderate density, densely packed or flocculent content. F cells were filled with oval or elliptic granules showing low density with a finely granular and flocculent matrix. X cells contained round granules with high density and homogeneous material. Gastric-type EC cells, intestinal-type EC cells, D cells, and D1 cells were represented in the cardiac, fundic and pyloric gland areas of the ovine abomasum. ECL cells and F cells were confined to the fundic glands, G cells and X cells to the pyloric glands.

Abomasum↗

PubMed1978

[Autoradiographic study of stimulation of RNA synthesis in fibroblasts].

The rate of uridine-5 3H incorporation into the skin-muscle wound fibroblasts of control and experimental animals, and also into the fibroblasts of flocculent connective tissue of intact animals was studied. The character of incorporation and distribution of the isotope in the nuclei and cytoplasm in the flocculent connective tissue fibroblasts differed in intact mice from those in the wound fibroblasts only by intensity. Potassium orotate RNA synthesis stimulation in the fibroblast nuclei closely correlated with the increased rate and intensity of the labeled RNA passage from the cell nuclei to the sites of collagen synthesis.

Animals↗

PubMed1981

Dimethylpolysiloxane as an adjuvant in double-contrast barium enema.

The value of Dimethylpolysiloxane (Simethicone) in the reduction of gas bubbles and foam formation, and in the prevention of flocculation of contrast medium during the double-contrast barium enema examination is presented. Altogether 600 unselected patients were studied, 300 with barium suspension diluted with 10 vol % of distilled water only, and 300 with the same suspension into which dimethylpolysiloxane was added. Simethicone significantly reduced gas bubbles and foam formation. It also prevented flocculation and cracking of mucosal coating, while it had no effect on the density of mucosal coating.

Adjuvants, Pharmaceutic↗

PubMedDate not supplied

[Use of microdispersed forms of crosslinked polyelectrolytes in biotechnology].

The interaction of microdispersions of crosslinked polyelectrolytes with ions of biologically active substances has been studied by physicochemical methods. The processes of ion exchange and physical adsorption, underlying the interaction, can promote flocculation. Of particular importance is the selective flocculation of dipolar ions of biologically active substances.

Biological Factors↗

PubMed1975

Studies on the pathogenesis of ischemic cell injury. II. Morphological changes of the pars convoluta (P1 and P2) of the proximal tubule of the rat kidney made ischemic in vivo.

The pars convoluta of the proximal tubules of the rat kidney was examined by means of light and electron microscopy after 15, 30, 60 and 120 min of complete ischemia produced by clamping of the aorta. The same ischemia periods were also examined after 24 hrs of blood reflow. It was found that the vast majority of the cells of pars convoluta survived 60 min of ischemia as seen after 24 hrs of reflow. The following pattern of changes were observed at time intervals up to 60 min: progressive clumping of chromatin, progressive distortion of microvilli with bleb formation, increasing dilatation and finally vesiculation of rough-surfaced endoplasmic reticulum and initially condensation and later high amplitude swelling of mitochondria. It is concluded that these subcellular changes are compatible with cell survival. Also tubule cells containing swollen mitochondria with small flocculent densities are potential candidates for survival. 120 min of ischemia was associated with marked mitochondrial swelling with large flocculent densities, severe cell damage and necrosis and was not compatible with cell survival. A working hypothesis is presented relative to the pathogenesis of acute renal failure caused by complete ischemia.

Acute Kidney Injury↗

PubMed1994

Comparison of a three-component acellular pertussis vaccine with a whole-cell pertussis vaccine in 15- through 20-month-old infants.

OBJECTIVE: To compare the immunogenicity and reactogenicity of a diphtheria and tetanus toxoids and three-component acellular pertussis vaccine (DTaP) with a diphtheria and tetanus toxoids and whole-cell pertussis vaccine (DTwP) when administered as a booster dose to infants 15 through 20 months of age. DESIGN: Randomized, double-blind, comparative study. SETTING: Three pediatric practices (two private; one hospital-based). PARTICIPANTS: One hundred and sixty-five healthy 15- through 20-month old infants. SELECTION PROCEDURES AND INTERVENTIONS: Infants were randomly assigned in a 2:1 ratio to receive vaccine from a single lot of DTaP or from commercially available DTwP. DTaP contained 25 micrograms of pertussis toxoid, 25 micrograms of filamentous hemagglutinin, 8 micrograms of pertactin (69-kilodalton outer membrane protein), 25 flocculating units of diphtheria toxoid, and 10 flocculating units of tetanus toxoid per 0.5-mL dose. DTwP contained one half the concentrations of diphtheria and tetanus toxoids compared with DTaP and a pertussis component with a potency of 4 U/0.5-mL dose. Serum samples were obtained on the day of immunization and 4 weeks later. Adverse reactions were recorded by parents for 7 days after immunization. An interval history was obtained 4 weeks after immunization. MEASUREMENTS AND RESULTS: IgG antibody to pertussis toxoid, filamentous hemagglutinin, pertactin, diphtheria toxoid, and tetanus toxoid was measured by an indirect enzyme-linked immunosorbent assay (ELISA) method. One month after immunization, the geometric mean antibody levels after DTaP compared with DTwP were: pertussis toxoid, 70.6 vs 28 ELISA U/mL (P = .003); filamentous hemagglutinin, 183.4 vs 43 ELISA U/mL (P < .001); pertactin, 216 vs 49.9 ELISA U/mL (P < .001); diphtheria, 14.1 vs 14.9 IU/mL (P = .74); and tetanus, 11.9 vs 14.8 IU/mL (P = .089). After immunization with DTaP, most local and systemic adverse experiences were significantly fewer compared with DTwP (P < .05). CONCLUSIONS: This three-component DTaP vaccine demonstrates significantly greater immune responses to pertussis toxoid, filamentous hemagglutinin, and pertactin, equivalent immune responses to diphtheria and tetanus toxoids, and significantly less reactogenicity compared with a licensed DTwP.

Antibodies, Bacterial↗