Experimental and calculated parameters on particle phagocytosis by alveolar macrophages.

Phagocytosis of three types of fluorescein-labeled test particles by rat alveolar macrophages (AM) were studied: spherical silica (3.2 microm), heat-killed Candida albicans (3.8 microm), and heat-killed Cryptococcus neoformans (6.1 microm) opsonized with specific IgG. These particles should attach to scavenger, mannose, and Fc receptors, respectively. Both control AM and AM pretreated for 20 h with interferon-gamma (12.5 or 50 U/ml) were studied. The sum of the number of attached and ingested particles per AM (accumulated attachment) was used as a measure of the attachment process, and the number of ingested particles per AM divided by the accumulated attachment (ingested fraction) was used as a measure of the ingestion process. The average ingestion time (IT), which is also a measure of the ingestion process, was calculated from the experimental data. The ingestion process was independent of the attachment process. IT increased with the time of observation. This is explained by the fact that IT determined from observation times shorter than the whole distribution of IT for a certain particle results in a shorter IT than the real average IT. C. albicans (mannose receptor) had the fastest ingestion process, C. neoformans opsonized with specific IgG (Fc receptor) had ingestion that was nearly as fast, and the silica particles (scavenger receptors) had the slowest ingestion process. Treatment with interferon-gamma markedly impaired the attachment process for all three types of particles (and three types of receptors) but clearly impaired the ingestion process only for silica particles (scavenger receptors).     

Localization of biotransformational enzymes along the crypt-villus axis of the rat intestine. Evaluation of two cell isolation procedures

Rat intestinal epithelial cells were isolated by EDTA-chelation, combined with gentle shaking (modified Weiser procedure) or with strong longitudinal vibration (Harrison/Webster procedure). Both methods yield large numbers of viable cells and are relatively easy to use. Electronmicroscopical and biochemical data indicate that cell fractions from different levels of the villous region can be obtained only by the modified Weiser procedure. When strong mechanical forces are involved (Harrison-Webster procedure) the villus epithelium is released according to an all-or-nothing process. The biotransformational capacity of cell fractions, obtained from different levels of the villi by the modified Weiser procedure, was investigated. It was shown that the rate of metabolism of 7-ethoxycoumarin and 1-naphthol was substantially higher in lower villous cells than in cells isolated from the upper villous region. O-Deethylation of 7-ethoxycoumarin decreases from 145 +/- 13 pmole/min mg cell protein (72 +/- 4% conjugated) in lower villous cells to 62 +/- 12 pmole/min mg cell protein (37 +/- 6% conjugated) in tip cells. Glucuronidation of 1-naphthol decreased from 495 +/- 23 pmole/min mg cell protein (lower villous cells) to 137 +/- 13 pmole/min mg cell protein (tip cells).     

AIDS and Glycosylation

The authors regret that in this Mini Review a paper by Massariet al. (1990) (J. Immunol., 144, 4628-4632) was cited out ofcontext. In this paper isolates of HIV-1 from peripheral bloodmononuclear cells of seropositive individuals (and not molecularclones as cited) were investigated for their macrophage tropismin vitro.     

Resuscitation with an AED: putting the data to use

The increased use of the automated external defibrillator (AED) contributes to the rising survival rate after sudden cardiac arrest in the Netherlands. When used, the AED records the unconscious person’s medical data (heart rhythm and information about cardiopulmonary resuscitation), which may be important for further diagnosis and treatment. In practice, ethical and legal questions arise about what can and should be done with these ‘AED data’. In this article, the authors advocate the development of national guidelines on the handling of AED data. These guidelines should serve two purposes: (1) to safeguard that data are handled carefully in accordance with data protection principles and the rules of medical confidentiality; and (2) to ensure nationwide availability of data for care of patients who survive resuscitation, as well as for quality monitoring of this care and for related scientific research. Given the medical ethical duties of beneficence and fairness, existing (sometimes lifesaving) information about AED use ought to be made available to clinicians and researchers on a structural basis. Creating a national AED data infrastructure, however, requires overcoming practical and organisational barriers. In addition, further legal study is warranted.