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Biomedical subjects

H Bruning

Publications and source records attributed to H Bruning.

17 recordsLinked to original sources
PubMed2003

Innovative reactor technology for selective oxidation of toxic organic pollutants in wastewater by ozone.

Ozonation can be a suitable technique for the pre-treatment of wastewater containing low concentrations of toxic or non-biodegradable compounds that cannot be treated with satisfactory results when only the traditional, less expensive biological techniques are applied. In this case, the oxidation process has to be made as efficient as possible, in order to reduce the coats of ozone addition and use. An efficient oxidation process with ozone can be obtained by focusing the oxidation with ozone selectively on the direct oxidation of toxic pollutants and to minimize ozone losses due to the decay of ozone in water. Supported by data of the rate constants of the reactions involved, a mathematical model was developed. It quantifies the ozone consumption by the process, and the share of ozone consumption by undesired side reactions, in several different reactor systems. Results obtained with this model indicate that a plug flow reactor (PFR) will be the most efficient design for the oxidation reactor. As an alternative, the cascaded tank reactor system (CTR), in which the ozone feed may be realized with less practical problems, might be considered. The traditional continuous flow stirred tank reactor (CFSTR) is shown to be the least efficient system.

Conservation of Energy Resources↗
PubMed2002

Remediation of fine fractions of dredged sediments by flotation.

In the Netherlands, large quantities of contaminated dredged sludge have to be deposited or treated in the near future. Because of the large amounts of small particles involved, successful treatment is difficult. In this study a new flotation method on laboratory scale was used as an alternative remediation technique. Dissolved air was used to create small bubbles. Tests were performed with the finest fractions of sediments of Overschie (Rotterdam) and Petrol Harbor (Amsterdam) sludges contaminated with Polycyclic Aromatic Hydrocarbons (PAH). Several agents and conditions were tested with respect to the flotation efficiency. For Overschie sludge the best results were obtained without collector and SDS as frother. The PAH concentration in the Froth was up to 8 times higher than that in the non-floating fractions. The collected amount of dry matter in the froth was around 13%. With a two step flotation, the PAH concentration of the non-floating "clean" fraction was reduced from 240 mg (kg d m(-1)) to 99 mg (kg d m(-1)). For Petrol Harbor sludge the best results were obtained with the alcohol-based frothers Aerofroth and Montanol. The flotation was less selective than with Overschie sediment. Around 50%. solids were collected in the froth and the PAH concentration in the Froth was around 2 times higher than in the Settled fraction and 3-5 times higher than in the fraction Remains.

Biodegradation, Environmental↗
PubMed2002

Heavy metals extraction from anaerobically digested sludge.

This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the research, called sequential chemical extraction (SCE). The work started with the well-known Tessier method followed by Veeken and by Sims and Kline SCE schemes. Afterwards, modified versions of Tessier and Veeken schemes were applied. The second phase, named chemical extraction using pH progressive changes, concerns an alternative to the extraction process. Four acids were tested: nitric, hydrochloric, oxalic and citric and the pH values as well as the time were varied. Some conclusions reveal that although modifying Tessier and Veeken schemes provides more consistent results, SCE is still an imperfect method regarding specificity and selectivity. Besides, it is not advisable to apply one SCE scheme developed for one specific situation to another one, once the accurateness of the method depends on several factors such as sort of material and chemicals, contact time, temperature, etc. The extraction efficiency increases using nitric or hydrochloric acids at low pH values, promoting high extraction efficiency level.

Bacteria, Anaerobic↗
PubMed2001

Biodegradability and change of physical characteristics of particles during anaerobic digestion of domestic sewage.

At the high-rate anaerobic treatment of domestic sewage, both biological and physical processes play an important role. Therefore, the anaerobic biodegradability of raw, paper-filtered and membrane-filtered sewage and black water has been investigated in batch experiments. Additionally, the effect of anaerobic digestion on physical characteristics, like particle size, surface tension and zeta-potential, of the present particles is studied. The biodegradability of domestic sewage and black water at 30 degrees C is almost similar (71-74%). Moreover, a high methanogenesis of the colloidal fraction in domestic sewage (86 +/- 3%) is achieved, showing that the low removal of colloidal particles in continuous high-rate anaerobic reactors is due to low physical removal rather than biodegradability. The lowest biodegradability is demonstrated for the dissolved fraction (62%). The results show that after anaerobic digestion the average radius of particles with diameter < 4.4 and < 0.45 microns increased for domestic sewage, while it decreased for black water. Part of the surface-active components in domestic sewage is not biodegraded during anaerobic batch digestion, as indicated by the development of the surface tension. The negative zeta-potential of all particles hardly changes during digestion, showing that colloidal interactions were not affected by anaerobic digestion.

Anaerobiosis↗
PubMed1993

A human monoclonal antibody, produced following in vitro immunization, recognizing an epitope shared by HLA-A2 subtypes and HLA-A28.

In vitro immunization and subsequent immortalization of peripheral blood cells of a multiparous woman has resulted in the production of a stable human mouse heterohybridoma, 5C2A2, secreting an HLA-A2/A28-specific human monoclonal antibody. Although possibly exposed to HLA-A2 by transfusions, the cell donor showed no HLA-A2-specific serum antibodies. The present protocol for in vitro immunization includes the elimination of suppressor cells from the responder cell population, the presence of irradiated allogeneic lymphocytes as a source of antigen, as well as stimuli--recombinant interleukin-2 and a B-cell specific nucleoside analogue--causing the proliferation of B lymphocytes, prior to immortalization. The ability of the antibody 5C2A2 to detect all known HLA-A2 subtypes, except A2.3, and A28, allows identification of the serological epitope on the HLA-A2 molecule. Application of this in vitro immunization method allows the production of a set of HLA monoclonal antibody-secreting human hybridomas, independent of the existence of serum HLA antibodies in the lymphocyte donors.

Amino Acid Sequence↗
PubMed1987

Differential expression of DRw52-like determinants detected by monoclonal antibodies.

The reactivity of three monoclonal antibodies (MoAb) directed against DRw52-like determinants was studied in relation to the reactivity of an anti-DR MoAb using fluorescence-activated cell sorter (FACS) analysis. The MCS-7 MoAb reacted with all DRw52+ cells and in addition with DR2+, DR4+, and a DR7+ cell. Both the I-LR2 and the 7.3.19.1 MoAb reacted with DR3+, DR5+, and DRw6+ cells only. However, whereas the 1-LR2 MoAb reacted strongly with all those cells compared with the anti-DR MoAb, the 7.3.19.1 MoAb reacted strongly with DR3+ cells only, and somewhat less with DR5+ and DRw6+ cells. The implications of this for the location of DRw52-like determinants on DR beta chains is discussed.

Antibodies, Monoclonal↗
PubMed1986

Identification of a new lymphocyte subset surface antigen, the expression of which disappears after in vitro and in vivo stimulation. Distribution, biochemistry, and functional studies.

Two monoclonal antibodies (MoAbs) are described (MD 2.6, IgG1 and MD 4.3, IgG2a) that react with a nonlineage specific lymphocyte subset surface antigen. This antigen is expressed on B cells, a subset of both T8+ and T4+ cells, cells that exert killer and natural killer cell activity in vitro, B cells in lymph nodes, and a small percentage of thymocytes. Expression of the antigen was found to be variable on T cells but not on B cells among individuals. Following polyclonal activation, expression of the determinant detected was lost from the cell surface. Both MD+ and MD+ cells responded to PHA and in MLC. MLC resulted in the generation of cytotoxic T lymphocytes and primed T lymphocytes in both the MD+ and MD+ subpopulations. In contrast, the response to soluble antigens was found to reside almost exclusively in the MD-subset. Immunoprecipitation indicates that the MoAbs react with an antigen that has a molecular weight of 220-240 KD which can be cleaved into subunits of 70-80 kD by beta-mercaptoethanol.

Antibodies, Monoclonal↗
PubMed1986

Antibody dependent cellular cytotoxicity mediated by HLA-class II specific monoclonal antibodies.

The ability of mouse monoclonal antibodies (MoAbs) directed against HLA-class II molecules to mediate in Antibody Dependent Cellular Cytotoxicity (ADCC) was investigated. The results indicate that both MoAbs to monomorphic and polymorphic HLA-DR and DQ determinants are able to mediate ADCC in an antigen specific manner. However, not all antibodies mediate ADCC to a similar extent. Furthermore, antibodies were identified that appeared to mediate ADCC in an HLA-DR haplotype dependent fashion. These results indicate that the inhibition of HLA-class II specific proliferative responses by anti-class II MoAbs may be influenced by ADCC directed against class II positive stimulator cells.

Animals↗
PubMed1985

A monoclonal antibody detecting an HLA-DQwl-related determinant.

A complement fixing monoclonal antibody (moab) was prepared which reacts with a polymorphic determinant on HLA class II molecules. The moab IIB3 recognises all DQwl (DC1, MB1, LB-E12) positive cells as well as some DR4, DR7, DRw8 and DRw9 positive cells. The moab reacts mainly with B-cells and not or with only a minority of the monocytes. Segregation of the determinant with HLA-DR could be shown. The determinant is strongly expressed on DR2, DR4 and DRw6 positive cell lines but only weakly on DR1 lines. In contrast to a monoclonal antibody against a monomorphic determinant on class II molecules IIB3 did not give a distinct inhibition of the MLC nor did it inhibit the generation of CTLs in MLC as has been described for the DQwl like moab BT 3/4 (Corte et al. 1982). Immunoprecipitation indicates that IIB3 reacts with DQ-like molecules.

Antibodies, Monoclonal↗
PubMed1984

A mouse monoclonal antibody detecting a DR-related MT2-like specificity: serology and biochemistry.

A mouse monoclonal antibody (7.3.19.1) was produced which reacts with class II molecules on B cells and monocytes of DR3, DR5, and/or DRw6 positive donors only. Using this moab and two others, three different groups of class II molecules could be identified. Furthermore, a differential precipitation pattern was found which correlates with a DR-related variable expression of the MT2-like polymorphic determinants on the cell surface. Addition of 7.3.19.1 to MLCs did not result in significant inhibition in controls to the two other moabs tested. Normal CTL activity was found in such a stimulated responder population.

Animals↗
PubMed1984

Ectopic adrenocortical tissue along the spermatic cord.

The subject of ectopic adrenal tissue along the spermatic cord is reviewed in respect of incidental finding during operation for undescended testis. The condition is probably more common than previously reported and embryology and clinical implications are briefly discussed. Nodules consisting of aberrant adrenal tissue should be removed whenever incidentally detected, but a routine search for them is not mandatory.

Adrenal Cortex↗
PubMed1979

Uptake of minute virus of mice into cultured rodent cells.

The uptake of minute virus of mice into cells in tissue culture was examined biochemically and by electron microscopy. Cell-virus complexes were formed at 4 degrees C, and uptake of virus was followed after the cells were shifted to 37 degrees C. The infectious particles appeared to enter cells at 37 degrees C by a two-step process. The first and rapid phase was measured by the resistance of cell-bound virus to elution by EDTA. The bulk of the bound virus particles became refractory to elution with EDTA within 30 min of incubation at 37 degrees C. The infectious particles became resistant to EDTA elution at the same rate. The second, slower phase of the uptake process was measured by the resistance of infectious particles to neutralization by antiserum. This process was complete within 2 h of incubation at 37 degrees C. During this 2-h period, labeled viral DNA became progressively associated with the nuclear fraction of disrupted cells. The uptake of infectious virus could occur during the G1 phase of the cell cycle and was not an S phase-specific event. The uptake process was not the cause of the S phase dependence of minute virus of mice replication. In electron micrographs, virus absorbed to any area of the cell surface appeared to be taken into the cell by pinocytosis.

Adsorption↗
PubMed1977

Specific binding sites for a parvovirus, minute virus of mice, on cultured mouse cells.

The early interactions between parvoviruses and host cells have not been extensively described previously. In this study we have characterized some aspects of viral binding to the cell surface and demonstrated the existence of specific cellular receptor sites for minute virus of mice (MVM) on two murine cell lines that are permissive for viral growth. The interaction had a pH optimum of 7.0 to 7.2, and both the rate and extent of the reactions were slightly affected by temperature. Mouse A-9 cells (L-cell derivative) had approximately 5 X 10(5) specific MVM binding sites per cell, and Friend erythroleukemia cells had 1.5 X 10(5) MVM sites per cell. In contrast, the nonpermissive mouse lymphoid cell line L1210 lacked specific viral receptors. Also, cloned lines of A-9 cells resistant to viral infection have been isolated. One of these lines lacked the "specific" virus attachment sites but exhibited low levels of nonsaturable virus binding. Based on these examples, infectivity is correlated with the presence of specific viral receptors on the cell surface.

Animals↗