We have developed a quadrupole magnetic flow sorter (QMS) to facilitate high-throughput binary cell separation. Optimized QMS operation requires the adjustment of three flow parameters based on the immunomagnetic characteristics of the target cell sample. To overcome the inefficiency of semiempirical operation/optimization of QMS flow parameters, a theoretical model of the QMS sorting process was developed. Application of this model requires measurement of the magnetophoretic mobility distribution of the cell sample by the cell tracking velocimetry (CTV) technique developed in our laboratory. In this work, the theoretical model was experimentally tested using breast carcinoma cells (HCC1954) overexpressing the HER-2/neu gene, and peripheral blood leukocytes (PBLs). The magnetophoretic mobility distribution of immunomagnetically labeled HCC1954 cells was measured using the CTV technique, and then theoretical predictions of sorting recoveries were calculated. Mean magnetophoretic mobilities of (1-3) x 10(-4) mm(3)/(T A s) were obtained depending on the labeling conditions. Labeled HCC1954 cells were mixed with unlabeled PBLs to form a "spiked" sample to be separated by the QMS. Fractional recoveries of cells for different flow parameters were examined and compared with theoretical predictions. Experimental results showed that the theoretical model accurately predicted fractional recoveries of HCC1954 cells. High-throughput (3.29 x 10(5) cells/s) separations with high recovery (0.89) of HCC1954 cells were achieved.

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PubMedDate not supplied

[Cardiotocographic findings in silent uterine rupture].

A silent hysterorrhexis in the expulsion phase and a second silent hysterorrhexis in the absence of labor, with the amniotic sac intact and the os uteri one centimeter wide were detected by external cardiotocography. In both cases there was a sudden loss of oscillation and suddenly persistent fetal bradycardia after the cardiotocogram had previously been normal. These findings are in agreement with the six cases of cardiotocographically documented silent hysterorrhexis published hitherto.

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[Cerebral calcifications in persons over the age of sixty].

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Adult↗

PubMedDate not supplied

Platelet-activating factor antagonists suppress the generation of tumor necrosis factor-alpha and superoxide induced by lipopolysaccharide or phorbol ester in rat liver macrophages.

Platelet-activating factor (PAF) has been shown to play an important role in the generation of tumor necrosis factor-alpha (TNF-alpha) and superoxide in guinea pig peritoneal macrophages. In this study, the effects of the PAF receptor antagonists, WEB 2170 and RP 59277, and of a PAF analogue, HAGPT, on TNF-alpha and superoxide production by rat Kupffer cells was investigated. The liver macrophages produced very little TNF-alpha and superoxide when exposed to PAF, but released substantial amounts of superoxide following treatment with zymosan or phorbol 12-myristate 13-acetate (PMA). WEB 2170 not only inhibited the generation of superoxide by PMA but also suppressed the LPS-induced TNF-alpha synthesis by Kupffer cells in a concentration-dependent manner. Northern blot analysis revealed that the expression of TNF-alpha mRNA induced by lipopolysaccharide (LPS) in Kupffer cells was partially abrogated by WEB 2170 or RP 59227. Furthermore, WEB 2170 reduced the PMA-induced leakage of lactate dehydrogenase (LDH) from Kupffer cells in a dose-dependent manner. These data suggest that TNF-alpha and superoxide syntheses in Kupffer cells are rather insensitive to exogenous PAF. On the other hand, the PAF antagonists used in this study interfere with the transduction of the signals induced by LPS, PMA or zymosan. It is questionable whether the PAF receptor of the plasma membrane is involved in the inflammatory response of rat Kupffer cells.

Animals↗

PubMedDate not supplied

Production of tumor necrosis factor-alpha, interleukin-1 and interleukin-6 in the perfused rat liver.

The kinetics of the production and release of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) and interleukin-6 (IL-6) were investigated in the perfused rat liver and in primary cultures of Kupffer cells after stimulation with lipopolysaccharide (LPS). A small and transient accumulation of TNF-alpha could be detected immunohistochemically and by cytotoxicity assay in the intracellular space about 1 h after addition of LPS to the cultured cells. TNF-alpha release in the perfused liver followed similar kinetics as those found in the serum of LPS-treated rats and in primary cultures of rat Kupffer cells. The cytotoxic TNF-alpha activity of the perfusate attained its maximum (11.5 +/- 2.6 U/ml) 90 min after LPS stimulation and remained nearly constant for further 150 min. 2 microM dexamethasone reduced the production of TNF-alpha by 10 g of liver during 240 min from 46 to 16 x 10(3) units. The production of IL-1 and IL-6 by 10 g of liver during the initial 240 min was 3 and 530 x 10(3) IU, respectively. The maximal concentrations of IL-1 (1.4 +/- 0.7 IU/ml) and IL-6 (157 +/- 60 IU/ml) were found 240 min after LPS addition. The production of IL-1 was totally suppressed by 2 microM dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMedDate not supplied

The metabolite deficit period as an approach to biochemical pathology.

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Animals↗