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At least 613 records · Page 34Linked to original sources
PubMed1988

Low frequency electric and magnetic fields have different effects on the cell surface.

There is a considerable controversy over the nature of weak electromagnetic-field effects in living organisms. Part of the controversy can be traced to a lack of understanding of whether electric or magnetic fields are involved in producing bioeffects. We find that both 60 Hz electric and magnetic fields alter the cell surface of Physarum polycephalum. Exposure to electric fields increases the negative charge on the cell surface while magnetic-field exposure decreases the hydrophobic character of the surface. These effects appear to be additive and independent of the waveform of the applied fields.

Cell Membrane↗
PubMed1990

No evidence of a countercurrent multiplier in the intestinal villus of the dog.

The hypothesis that a countercurrent multiplier within the intestinal villus increases osmolality in the distal villus tip was tested. Total sodium, potassium, and water content of intestinal tissue samples was measured. The results showed no significant difference in the total Na plus K concentration (millimoles per kilogram H2O +/- SEM) between the villi tips (185.1 +/- 7.7), whole villi (179.8 +/- 5.4), or intestine minus villi (177.2 +/- 1.7). In contrast, in the kidney (where the existence of a countercurrent multiplier has been demonstrated), the renal medulla had a total Na plus K concentration of 284 +/- 17.1 that was significantly more than the renal cortical concentration of 163 +/- 3.1. Villous tissue osmolality should be in osmotic equilibrium with intestinal luminal fluid. Sampling of intestinal luminal fluid revealed a total Na plus K concentration of 145-165 mmol/kg H2O, a figure compatible with normal luminal osmolality of 280-320 mosmol/kg H2O. These results deny the existence of a countercurrent multiplier in the intestinal villus of the dog.

Animals↗
PubMed1996

Countercurrent chromatographic analysis of ovalbumin obtained from various sources using the cross-axis coil planet centrifuge.

The present studies have been conducted to investigate the cause of an unusually broad peak of ovalbumin obtained by countercurrent chromatography (CCC) reported earlier [K. Shinomija et al., J. Chromatogr., 644 (1993) 215]. A series of CCC experiments using our prototyte of the cross-axis coil planet centrifuge revealed that commercial ovalbumin products were classified into two groups: group A formed two peaks of ovalbumin at pH 7.0 and 5.8, while group B showed a relatively sharp single peak in a broad range of pH. Electrophoresis indicated that the group A ovalbumin consisted of both natural and denatured products: the natural ovalbumin is a monomer (Mr 45 000) whereas the denatured products form dimers (Mr 90 000). The abnormally broad peak obtained from the group A ovalbumin at pH 9 is apparently caused by the heterogeneity of the sample protein.

Animals↗
PubMed1975

Detection of hepatitis B antibody by a single-antibody radioimmunoassay.

A radioimmunoassay (RIA) for the measurement of antibody to hepatitis B surface antigen (anti-HB-s) in human and non-human sera is described. The principle is based upon our earlier observation that anti-HB-s and hepatitis B surface antigen (HB-s-Ag) are soluble in 4.5% w/v polyethylene glycol 4000 but that anti-HB-s-HB-s-Ag complex is precipitated. The use of activated charcoal suspended in polyethylene glycol and dextran solution facilitated the separation of this complex by centrifugation, thus improving reproducibility and sensitivity. The test is approx. 3-5000 times as sensitive as counterelectrophoresis. In a survey of a normal blood donor population, with an incidence of approx. 0.1% positive for HB-s-Ag by RIA, 7-8% were found to have anti-HB-s by this method.

Animals↗
PubMed1983

A system for obtaining large numbers of cryopreserved human monocytes purified by leukapheresis and counter-current centrifugation elutriation (CCE).

A system has been developed for the isolation of large numbers of unfractionated mononuclear cells from single, well characterized normal individuals and for the separation by elutriation of these cells into populations of greater than 90% pure monocytes and greater than 99% pure lymphocytes. The total number of monocytes obtained from a single donor averaged about 550 million. After cryopreservation and thawing of these cells, the viability remained greater than 90%, 80% of original cells were recovered, and the ability to ingest antibody-coated targets was comparable to that of fresh monocytes. The cells remained sterile without the use of antibiotics and were suitable for long-term culture. The monocytes that were isolated and cryopreserved by these procedures functioned reproducibly as inhibitors of tumor cell growth and in an assay of responsiveness to monocyte migration inhibitory factor (MIF).

Blood Preservation↗
PubMed1983

Analysis of human peripheral blood lymphocytes isolated by counterflow centrifugation-elutriation.

Human peripheral blood mononuclear cells isolated by Ficoll-Hypaque density gradient centrifugation have been fractionated by counterflow centrifugal elutriation (CCE). Six CCE fractions were obtained and subsequently analyzed as for their content of monocytes, T cells, NK cells and B cells. The various cell types were identified through the expression of specific surface membrane determinants or by cytochemical staining for alpha-naphthyl acid esterase (ANAE). Monocytes were elutriated at the highest counterflow rates whereas the majority of B cells were collected at the lowest counterflow rates. T cells as well as NK cells were mostly concentrated in the intermediate fractions. No differences in the elutriation profile of T cells with the helper-inducer or with the cytotoxic-suppressor surface phenotype were observed. However, the percentages of T cells as determined by surface marker expression decreased with increasing counterflow rates, whereas the percentage of ANAE-positive T cells increased. Yet, T cells recovered at the high counterflow rates had ANAE-reactive organelles larger than those of T cells collected at low counterflow rates. These findings suggest that T cells at different maturational stages could be separated by CCE.

B-Lymphocytes↗
PubMed1986

Counter current line deflection immunoelectrophoresis. A technique for the quantification of antibodies.

Combining the electrophoretic principles of counter current immunoelectrophoresis and deflection of line precipitates in line immunoelectrophoresis provides a new technique for quantitative determination of antibodies against specific antigens (CCLD electrophoresis), even if no purified antigen or monospecific antibodies are available for construction of the detection system. We have used the method for quantitative determination of antibodies against the flagellum of Treponema phagedenis biotype Reiter and compared the diagnostic potential of this method in the diagnosis of syphilis with an ELISA method for the quantification of IgG antibodies against the flagellum. The CCLD electrophoresis could be optimized to a diagnostic performance very similar to that achieved using the ELISA method.

Animals↗
PubMed1988

Countercurrent centrifugal elutriation in a table-top centrifuge.

An elutriation system has been developed which fits into a small table-top centrifuge. The new CS1 rotor functioned as accurately as the JE-6 rotor, commercially available from Beckman Instruments. However, fewer cells were required for the separation experiments. Leukocytes obtained from 25 ml whole blood by Ficoll-Hypaque gradient centrifugation were sufficient for separating lymphocytes from monocytes and for purifying granulocytes. Furthermore, when lymphocytes were harvested from cell cultures 40 ml of a suspension of 1.2 x 10(6) cells/ml were enough to yield an enriched preparation of antibody producing cells.

Antibody-Producing Cells↗