Demonstration of Tokamak Discharge Shutdown with Shell Pellet Payload Impurity Dispersal.

The first rapid tokamak discharge shutdown using dispersive core payload deposition with shell pellets has been achieved in the DIII-D tokamak. Shell pellets are being investigated as a possible new path toward achieving tokamak disruption mitigation with both low conducted wall heat loads and slow current quench. Conventional disruption mitigation injects radiating impurities into the outer edge of the tokamak plasma, which tends to result in poor impurity assimilation and creates a strong edge cooling and outward heat flow, thus requiring undesirable high-Z impurities to achieve low conducted heat loads. The shell pellet technique aims to produce a hollow temperature profile by using a thin, low-ablation shell surrounding a dispersive payload, giving a greatly increased impurity ablation (and radiation) rate when the payload is released in the plasma core. This principle was demonstrated successfully using 3.6 mm outer diameter, 40 µm thickness diamond shells holding boron powder. The pellets caused rapid (<10 ms) discharge shutdown with low conducted divertor heat fluence (∼0.1 MJ/m^{2}). Confirmation of massive release of the boron powder payload into the plasma core was obtained spectroscopically. Some evidence for the formation of a hollow temperature profile during the shutdown was observed. These first results open a new avenue for disruption mitigation research, hopefully enabling development of highly effective methods of avoiding disruption wall damage in future reactor-scale tokamaks.

Ex vivo porcine vaginal mucosal model of infection for determining effectiveness and toxicity of antiseptics.

AIMS: To develop a semi-high-throughput ex vivo mucosal model for determining efficacy and toxicity of antiseptics. METHODS AND RESULTS: Explants (5 mm) from freshly excised, porcine vaginal mucosa were infected with methicillin-sensitive Staphylococcus aureus (1 × 10(6)  CFU) at the epithelial surface for 2 h. Haematoxylin and eosin staining revealed healthy uninfected tissue and only minor disruptions in tissue infected with methicillin susceptible Staph. aureus (MSSA), which remained in outer epithelial cell layers. After 2 h infection, 10 µl of chlorhexidine digluconate (CHG, 3%), povidone-iodine (PI, 7·5%), octenidine dihydrochloride (OCT, 0·1%) or polyhexamethylene biguanide (PHMB, 0·1%) was applied. Antiseptics significantly reduced MSSA (1-4 log10  CFU/explants) after 0·25 h to 4 h. CHG, PHMB and OCT exhibited persistence at 24 h. In broth culture, CHG 0·012% and PI 0·625% achieved >6 log10 reductions at 2 h. PI-based formulations were more efficacious than unformulated PI. PI-based formulations exhibited no significant cytotoxicity on explants using an MTT assay. CONCLUSIONS: All antiseptics tested in the mucosal MSSA infection model reduced MSSA. CHG and PI were more potent in broth culture. SIGNIFICANCE AND IMPACT OF THE STUDY: We developed a semi-high-throughput mucosal model that can identify compounds or formulations with promising antimicrobial and limited cytotoxic properties.

Reduction of edge-localized mode intensity using high-repetition-rate pellet injection in tokamak H-mode plasmas.

High repetition rate injection of deuterium pellets from the low-field side (LFS) of the DIII-D tokamak is shown to trigger high-frequency edge-localized modes (ELMs) at up to 12× the low natural ELM frequency in H-mode deuterium plasmas designed to match the ITER baseline configuration in shape, normalized beta, and input power just above the H-mode threshold. The pellet size, velocity, and injection location were chosen to limit penetration to the outer 10% of the plasma. The resulting perturbations to the plasma density and energy confinement time are thus minimal (<10%). The triggered ELMs occur at much lower normalized pedestal pressure than the natural ELMs, suggesting that the pellet injection excites a localized high-n instability. Triggered ELMs produce up to 12× lower energy and particle fluxes to the divertor, and result in a strong decrease in plasma core impurity density. These results show for the first time that shallow, LFS pellet injection can dramatically accelerate the ELM cycle and reduce ELM energy fluxes on plasma facing components, and is a viable technique for real-time control of ELMs in ITER.

Mechanisms underlying the inhibition of the cytochrome P450 system by copper ions.

Copper toxicity has been associated to the capacity of free copper ions to catalyze the production of superoxide anion and hydroxyl radical, reactive species that modify the structure and/or function of biomolecules. In addition, nonspecific Cu2+-binding to thiol enzymes, which modifies their catalytic activities, has been reported. Cytochrome P450 (CYP450) monooxygenase is a thiol protein that binds substrates in the first and limiting step of CYP450 system catalytic cycle, necessary for the metabolism of lipophilic xenobiotics. Therefore, copper ions have the potential to oxidize and bind to cysteinyl residues of this monooxygenase, altering the CYP450 system activity. To test this postulate, we studied the effect of Cu2+ alone and Cu2+/ascorbate in rat liver microsomes, to independently evaluate its nonspecific binding and its pro-oxidant effects, respectively. We assessed these effects on the absorbance spectrum of the monooxygenase, as a measure of structural damage, and p-nitroanisole O-demethylating activity of CYP450 system, as a marker of functional impairment. Data obtained indicate that Cu2+ could both oxidize and bind to some amino acid residues of the CYP450 monooxygenase but not to its heme group. The differences observed between the effects of Cu2+ and Cu2+/ascorbate show that both mechanisms are involved in the catalytic activity inhibition of CYP450 system by copper ions. The significance of these findings on the pharmacokinetics and pharmacodynamics of drugs is discussed.

Inhibition of cytosolic glutathione S-transferase activity from rat liver by copper.

H(2)O(2) inactivation of particular GST isoforms has been reported, with no information regarding the overall effect of other ROS on cytosolic GST activity. The present work describes the inactivation of total cytosolic GST activity from liver rats by the oxygen radical-generating system Cu(2+)/ascorbate. We have previously shown that this system may change some enzymatic activities of thiol proteins through two mechanisms: ROS-induced oxidation and non-specific Cu(2+) binding to protein thiol groups. In the present study, we show that nanomolar Cu(2+) in the absence of ascorbate did not modify total cytosolic GST activity; the same concentrations of Cu(2+) in the presence of ascorbate, however, inhibited this activity. Micromolar Cu(2+) in either the absence or presence of ascorbate inhibited cytosolic GST activity. Kinetic studies show that GSH but no 1-chloro-2,4-dinitrobenzene prevent the inhibition on cytosolic GST induced by micromolar Cu(2+) either in the absence or presence of ascorbate. On the other hand, NEM and mersalyl acid, both thiol-alkylating agents, inhibited GST activity with differential reactivity in a dose-dependent manner. Taken together, these results suggest that an inhibitory Cu(2+)-binding effect is likely to be negligible on the overall inhibition of cytosolic GST activity observed by the Cu(2+)/ascorbate system. We discuss how modification of GST-thiol groups is related to the inhibition of cytosolic GST activity.

Effect of parallel flows and toroidicity on cross-field transport of pellet ablation matter in tokamak plasmas.

The first complete set of time-dependent equations describing the cross-field drift of ionized pellet ablation matter in tokamak plasma caused by polarization in the nonuniform magnetic field has been developed and solved numerically. Important new features impacting the drift dynamics have been identified, including the effect of pressure profile variations in the tokamak plasma, curvature drive by near-sonic field-aligned (parallel) flows, and the rotational transform of the magnetic field lines, and are considered from the viewpoint of the parallel vorticity equation. These new features are necessary to obtain favorable quantitative agreement between theory and experimental fuel deposition profiles for both inner and outer wall launched pellet injection cases on the DIII-D tokamak.

First Report of Pathogenicity Groups 3 and 4 of Leptosphaeria maculans on Canola in North Dakota.

Blackleg, caused by Leptosphaeria maculans (Desmaz) Ces. & de Not (anamorph = Phoma lingam), is an economically important disease of canola (Brassica napus L.) worldwide and was first detected in North Dakota in 1991 (3). L. maculans can be categorized into one of several pathogenicity groups (PGs) on the basis of the interaction phenotypes in differential canola cvs. Westar, Glacier, and Quinta by using a standard screening protocol in the greenhouse (4). With this system, PG1 strains are weakly virulent and PG2, PG3, and PG4 are highly virulent. The predominant strains of L. maculans in North Dakota are PG1 and PG2 (3). In cooperation with the Oilseed Pathology Lab in the Department of Plant Science, University of Manitoba, blackleg-infested canola stubble was collected arbitrarily from fields in North Dakota during August and September of 2003. Isolates of the pathogen were obtained by plating surface-sterilized (2% NaOCl), collected stubble on V8 agar containing 0.03% chloramphenicol at 22°C under continuous cool-white fluorescent light. Pycnidiospores were harvested from single pycnidia after 14 days of incubation with the Miracloth filtering method (2) and stored at -20°C. Each isolate was passed once through cv. Westar to maintain virulence. Isolates were confirmed as being L. maculans by the presence of characteristic pink pycnidia formed on V8 agar and the characteristic symptoms caused on inoculated cotyledons of cv. Westar. The PG test was performed using a standard screening protocol (4) and was repeated three times for each isolate. For each isolate, 12 7-day-old cotyledons of each differential cultivar were wound inoculated with 10 µl of a pycnidiospore suspension (1 × 107 per ml). Disease severity on cotyledons was assessed 12 days after inoculation with a 0 to 9 scale (0 to 2 = resistant; 3 to 6 = intermediate; and 7 to 9 = susceptible). A total of 106 isolates were obtained from the stubble collected from 47 fields. Of these isolates, three were characterized as PG1, 94 as PG2, six as PG3, and one as PG4; two isolates could not be characterized according to the PG system as described (4). PG3 isolates originated from two fields in Cavalier County and one field in Ward County. The PG4 isolate was from Cavalier County. To our knowledge, this is the first time highly virulent strains of PG3 and PG4 have been detected in North Dakota. PG3 and PG4 strains of L. maculans were found only recently in western Canada (1,2). The discovery of these PGs in North Dakota and western Canada has immense implication to canola breeding programs and blackleg control, since these PGs may cause greater levels of blackleg severity on canola cultivars that are resistant to only PG2 type isolates. References: (1) Y. Chen and W. G. D. Fernando. Plant Dis. 89:339, 2005. (2) W. G. D. Fernando and Y. Chen. Plant Dis. 87:1268, 2003. (3) H. A. Lamey and D. E. Hershman. Plant Dis. 77:1263, 1993. (4) A. Mengistu et al. Plant Dis. 75:1279, 1991.

First Report of Blackleg Disease Caused by Leptosphaeria maculans on Canola in Brazil.

Canola (Brassica napus L.) is a relatively new crop in Brazil, having been grown there for approximately 8 years. In 2000, leaf lesions and stem cankers were observed in cvs. Hyola 420 and Hyola 401 in farmers' fields in the state of Rio Grande do Sul. Cankered stems were received at the University of Manitoba, Canada, from Rio Grande do Sul for disease identification. Small pieces of the stem were cut from the cankered area, and standard protocol was followed to surface sterilize the stem pieces. Stem pieces were plated on V8 agar medium and incubated under light for 12 days. Typical fungal colonies with concentric rings containing pycnidia formed on the V8 agar. The colony characteristics were typical of the blackleg pathogen, Leptosphaeria maculans (Desmaz.) Ces. & De Not. (anamorph = Phoma lingam) (Tode:Fr.) Desmaz.). Blackleg is an economically important and serious disease in many parts of the world including Australia, Canada, the United States, and Europe. L. maculans strains can be characterized in four pathogenicity groups (PG1 through PG4) based on differential testing procedures giving interaction phenotype (IP) reactions (2). Two weeks after plating on V8 media, plates were flooded with sterile distilled water, and pycnidiospores were harvested. Flats of multipots filled with Metro Mix were seeded with three cultivars (Westar, Glacier, and Quinta). One-week-old cotyledons from the three cultivars were inoculated with pycnidiospore suspensions (2 × 107 pycnidiospores per ml) of seven Brazilian isolates, numbered 7, 8, 9, 11, 15, 16, and 18, respectively. Each cotyledon leaf, punctured in the center with a needle, was inoculated with a 10-µl droplet of the inoculum. Disease evaluations were made 11 days after inoculation using a 0 to 9 rating scale (1). This screening was repeated three times from February 2001 to October 2001. After the second repeat, the isolates from Rio Grande do Sul were passed through the highly susceptible canola cv. Westar. Results from all four trials were consistent, and yielded one PG1 isolate (No. 7) and six PG3 isolates. PG1 is classified as a nonaggressive strain, whereas PG3 isolates are classified as aggressive. PG3 isolates would have an IP reaction of 7 to 9, 7 to 9, and 3 to 6 on cvs. Westar, Glacier, and Quinta, respectively. PG2 is the most commonly found aggressive strain in the Canadian prairies. PG3 is predominantly found in Australia, the United Kingdom, and the United States. To our knowledge, this is the first report of blackleg disease caused by L. maculans on canola in Brazil. Differential testing fulfilled Koch's postulates and determined the PG groups found in Brazil (PG1 and PG3). References: (1) P. A. Delwiche. Genetic aspects of blackleg (Leptosphaeria maculans) resistance in rapeseed (Brassica napus) Ph.D. thesis. University of Wisconsin-Madison, 1980. (2) A. Mengistu et al. Plant Dis. 75:1279, 1991.

Spatial uniformity of laser-accelerated ultrahigh-current MeV electron propagation in metals and insulators.

The evolution of laser-generated MeV, MA electron beams propagating through conductors and insulators has been studied by comparing measurement and modeling of the distribution of MeV protons that are sheath accelerated by the propagated electrons. We find that electron flow through metals is uniform and can be laser imprinted, whereas propagation through insulators induces spatial disruption of the fast electrons. Agreement is found with material dependent modeling.

Mitigation of tokamak disruptions using high-pressure gas injection.

High-pressure gas-jet injection of neon and argon is shown to be a simple and robust method to mitigate the deleterious effects of disruptions on the DIII-D tokamak. The gas jet penetrates to the central plasma at its sonic velocity. The deposited species dissipates >95% of the plasma by radiation and substantially reduces mechanical stresses on the vessel caused by poloidal halo currents. The gas-jet species-charge distribution can include >50% fraction neutral species which inhibits runaway electrons. The favorable scaling of this technique to burning fusion plasmas is discussed.

Use of an intensity ratio to describe breastfeeding exclusivity in a national sample.

Breastfeeding behavior in a sample of 1863 mother-infant pairs was examined using data from the 1988 National Maternal-Infant Health Survey. Breastfeeding behavior was operationalized as an intensity ratio, calculated as the number of breast milk feeds (on average in 24 hours) divided by the total number of all liquid feeds (on average in 24 hours), with a range from 0 to 1.0. During the first month postpartum, 61% of the sample reported exclusive breastfeeding, declining to 31% during months 2-3 postpartum and to 13% during months 4-6 postpartum. This decline was consistent with the linear decline in the mean intensity ratio, .82, .55, and .31, respectively, during the same three time periods. A higher breastfeeding intensity ratio was significantly associated with longer duration of breastfeeding, up to 1 year of life. Intensity ratio, as a measure of exclusivity, is a useful outcome measure for monitoring breastfeeding behavior.

A randomized controlled trial of a pediatric asthma outreach program.

BACKGROUND: Previous studies have shown that asthma education and case management may reduce asthma emergency care, hospitalizations, and expenditures. OBJECTIVE: We sought to study the effect of an asthma outreach program (AOP), a team-based, case-management intervention, on emergency ward (EW) and hospital use. METHODS: Fifty-seven patients aged 1 to 15 years with the diagnosis of asthma based on the usual clinical practice criteria who were continuously enrolled in a staff-model health maintenance organization for a period of at least 2 consecutive years were randomized into 2 intervention groups. The control group received a single intensive asthma education intervention, and the AOP group received the same initial education but then was followed-up by an asthma case management nurse throughout the intervention period. RESULTS: EW visits, hospitalizations, and total outside-of-health-plan expenditures (consisting of EW and hospital expenses, as well as miscellaneous costs, such as ambulance, durable medical equipment, tertiary referrals, and home care) were assessed from claims filed for a year before and after enrollment. Control group patients experienced significant reductions in EW visits (39%), hospitalizations (43%), and outside-of-health-plan costs (28%), possibly as a result of the baseline educational intervention received by all enrolled patients, in conjunction with regression to the mean. AOP group patients experienced significant reductions in EW visits, (73%, P =.0002), hospitalizations (84%, P =.0012), and outside-of-health-plan use (82%, P <.0001). When compared with the control group, AOP group patients demonstrated additional significant reductions in EW visits (57%, P <.05), hospitalizations (75%, P <.05), and outside-of-health-plan use (71%, P <.001). Estimates of direct savings to the health plan ranged from $7.69 to $11.67 for every dollar spent on the AOP nurse's salary, depending on assumptions. CONCLUSIONS: Asthma patients in a staff-model health maintenance organization decreased their resource use between 57% to 75% by participation in an AOP as compared with a randomized control group receiving only an educational intervention. Substantial savings were achieved compared with the cost of the AOP nurse.

Clinical approaches in the assessment of childbearing fatigue.

Modifications of the Fatigue Symptoms Checklist can be used clinically to assess fatigue during the childbearing year. Data from a series of studies provide beginning norms that can be used to interpret clinical scores and point to the potential importance of assessments to pregnancy complications and maternal performance. Consistent with North American Nursing Diagnosis Association (NANDA) definition of fatigue and the theory of unpleasant symptoms, fatigue and performance are important phenomena critical to the experience of pregnancy and assumption of the maternal role.

What happens when fatigue lingers for 18 months after delivery?

OBJECTIVE: To understand the consequences when mothers experience fatigue throughout the first 18 months after birth. DESIGN: Secondary analysis of data from a longitudinal study. Fatigue was measured five times between birth and 18 months after delivery. SETTING: Data for the longitudinal study were collected in different settings (hospital, telephone, and homes). PARTICIPANTS: White mothers who delivered full-term neonates of normal birth weight in a community hospital (N=229). MAIN OUTCOME MEASURES: Persistent fatigue was operationally defined as the report of at least one symptom of fatigue at all five time periods. The association between persistent fatigue and performance outcomes (maternal health, infant health, and infant development) was tested. RESULTS: Results were significant using alpha of .05. Persistent fatigue is associated with perceived maternal health and infant development at 18 months but not infant health. CONCLUSIONS: Findings suggest that persistent fatigue may have a negative effect on performance outcomes for mothers and infants. Assessment for fatigue symptoms should be part of each nursing contact and interpreted as a pattern. Helping mothers choose methods of symptom relief and energy conservation can benefit both the mother and the infant.

Carotid endarterectomy in the elderly.

BACKGROUND AND PURPOSE: Increasing life expectancy has resulted in an increasing number of elderly. As the elderly population grows, the incidence of stroke will increase. Many such strokes result from carotid stenosis (CS). In view of the benefits of carotid endarterectomy (CEA) shown in recent clinical trials, it would seem prudent that surgery for CS be considered for prevention of stroke in this population. Traditionally, members of the geriatric population have often been viewed, perhaps arbitrarily, as inappropriate candidates for CEA because of perceived greater operative risks. The purpose of this study was to assess the safety of performing CEA in geriatric patients. PATIENTS AND METHODS: A total of 175 patients who underwent CEA between January 1994 and June 1996 were evaluated retrospectively. The patients were divided into the nongeriatric group (NGG <75 years of age) and the geriatric group (GG >75 years of age). There were 90 (51%) patients in the NGG and 85 (49%) in the GG. The two groups were compared for the following: rationale for surgery (symptomatic vs. asymptomatic), risk factor profile, preoperative imaging studies (noninvasive vs. invasive), and complications of surgery. RESULTS: Both groups were generally comparable in terms of their risk factors, rationale for surgery, and preoperative cardiac risk. Noninvasive imaging alone was used in 56% of NGG and 60% of GG patients, whereas 44% of NGG and 40% of GG underwent invasive cerebral angiography in addition to other noninvasive studies. There were 4(4.4%) postoperative neurological complications, including two strokes and two transient ischemic attacks (TIAs), in the NGG and 1(1%) stroke in the GG. One patient died in the NGG from a stroke. Although one patient in the GG experienced a postoperative myocardial infarction, there was no mortality in this group. CONCLUSION: CEA can be safely performed for both symptomatic and asymptomatic CS in appropriately selected patients irrespective of age.

Histological characterization of a delayed wound healing model in pig.

Chronic wounds, such as venous ulcers and pressure ulcers, frequently remain unresponsive to currently available treatments. Several animal models of wound healing have been published, including models of impaired healing developed to mimic the clinical condition of chronic wounds better. We used a delayed wound healing model in the pig that uses irradiation of the skin prior to creation of the surgical wounds and characterized it histologically. Radiation was used on one side of the back prior to making four full-thickness wounds on each side. Clinical observations were performed to record granulation tissue, reepithelialization, and wound area as a function of time. Histology data were obtained at 1, 2, 3, and 4 weeks, and slides were stained with hematoxylin and eosin for general observations. Immunohistochemistry was performed using laminin as a marker for blood vessels, and the number, size, and circularity of blood vessels found in the granulation tissue were measured. Our results show that this model causes a delay in wound healing that is mostly apparent between days 7 and 15. Granulation tissue took more time to form and fill the wounds on the irradiated side, and blood vessels were slower to develop. Blood vessels were larger and more irregular in shape on the irradiated side than on the control side. After 2 weeks, healing resumed, indicating that the induced damage was not irreversible. These results suggest that this model can be used to test the effects of therapeutic approaches intended to treat chronic wounds.

Outcomes for control patients referred to a pediatric asthma outreach program: an example of the Hawthorne effect.

A study was designed to determine whether identification of high risk for exacerbations of asthma based on pediatrician concern, emergency department visits, or hospital stays results in a decrease of resource utilization because of referral to an asthma outreach program even if the intervention does not take place. The findings for such a group were compared with those for a group who did undergo intervention with an asthma outreach program. Fifty-six patients 1 to 14 years of age were assigned to one of two groups. The control group (those who did not undergo intervention) had consistent but not statistically significant reductions in utilization of emergency visits, hospitalizations, and dollars spent (21%, 24%, and 32%, respectively). The group who underwent intervention with the asthma outreach program had large and statistically significant decreases in the same parameters (emergency visits, 60%, P = 0.001; hospital stays, 74%, P = 0.008; dollars spent, 72%, P = 0.004). However, the apparently insignificant effect of the reductions in utilization by the control group substantially altered interpretation of the outcomes of the study. Cost savings were reduced from $11.69 per dollar spent on intervention to $6.49 per dollar spent. In before-and-after studies such as those typically conducted during continuous quality improvement projects, which typically do not have control groups, investigators need to consider control group effects when they assess the results of intervention.

Evaluation of two intervention strategies to stimulate quality improvement projects in the hospital: the H. pylori example.

A multistate quality improvement project conducted to improve the care of hospitalized Medicare patients with peptic ulcer disease is described. This randomized control study design compared the effectiveness of two intervention strategies (mailed information vs. on-site presentations with feedback) in stimulating hospitals to conduct diagnostic journeys to determine root causes for performance deficits and to develop and implement plans to improve performance.

Adolescent idiopathic scoliosis and the presence of spinal cord abnormalities. Preoperative magnetic resonance imaging analysis.

STUDY DESIGN: Preoperative magnetic resonance imaging was performed on 45 consecutive patients diagnosed with adolescent idiopathic scoliosis to evaluate the brain and spinal cord. OBJECTIVES: To investigate the prevalence of spinal cord abnormalities in patients undergoing surgery for adolescent scoliosis. SUMMARY OF BACKGROUND DATA: A review of the literature indicates that the number of abnormalities of the brain stem and spinal cord reported with magnetic resonance imaging in patients with idiopathic scoliosis is increasing. METHODS: Forty-five consecutive patients with idiopathic adolescent scoliosis were examined with magnetic resonance imaging to rule out underlying pathologic abnormalities of the brain stem or spinal cord. RESULTS: Two of 45 patients had abnormal findings on magnetic resonance imaging. One patient had a cervical cord syrinx from C4-T2 with an Arnold-Chiari malformation; the other patient had a syrinx from C6-C7. CONCLUSIONS: This study reports a higher than expected frequency of spinal cord abnormalities in patients with the preoperative diagnosis of adolescent idiopathic scoliosis. The indications for preoperative magnetic resonance imaging before spinal fusion vary among physicians; however, strict adherence to previously published recommendations as listed in this report is advisable. It appears from the results of this study that by following these guidelines, small syrinxes may remain undetected, but the clinical significance of this is unknown.

Expression of intercellular adhesion molecule-1 on macrophages in vitro as a marker of activation.

Macrophage activation is a major component of wound healing. It also determines the extent of inflammatory reactions and the response of the body to implanted materials. We have previously shown, using an in vitro model, that the extent of spreading of macrophages on different materials is a marker of activation, and that a soluble inducer has a dose-response effect on the secretion of cytokines in the culture medium. This work investigates the expression of three different cell surface markers [macrophages MAC-1, MAC-3 and intercellular adhesion molecule-1 (ICAM-1)] on macrophages in vitro using confocal microscopy and shows that ICAM-1 is also a marker of macrophage activation in this model. We observed increased amounts of ICAM-1 on activated macrophages compared to unactivated macrophages, whereas MAC-1 and MAC-3 were either expressed constitutively or demonstrated no quantitative change in expression after activation under the same experimental conditions. We also tested the expression of ICAM-1 with various concentrations of soluble inducers (lipopolysaccharide, 0.001, 0.01, 0.1, 1 and 10 micrograms ml-1. S-27609, 0.1, 0.25, 0.5, 1, 2 and 3 micrograms ml-1 and on a sheet of polylactic acid alone or in combination with soluble inducers. All doses of soluble inducers induced the expression of ICAM-1 on cells grown in glass chamber slides. The induction was not dose related but seemed to work rather in an on-off manner. There was no effect of material on ICAM-1 expression on the cell surface when no soluble inducer was added. This was similar to cytokine secretion, which was not induced by our material alone. When either lipopolysaccharide or S-27609 was used in combination with the material, there was an increase in the average measured intensity of ICAM-1. In this in vitro model, ICAM-1 staining as measured by confocal microscopy is a marker for macrophage activation. Our results suggest that the extent of macrophage activation as measured by ICAM-1 and by cytokine secretion is more sensitive to soluble inducers than to the action of the flat sheet of polylactic acid.