Fatigue during preoperative chemoradiation for resectable rectal cancer

BACKGROUND

The aim of this study was to evaluate the severity and patterns of fatigue during preoperative chemoradiation therapy for locally advanced rectal cancer and determine whether there are predictors for patients who develop severe fatigue.

METHODS

Seventy-two patients with resectable rectal cancer received chemoradiation (total radiation dose, 45 gray/25 fractions to the pelvis; continuous infusion of 5-fluorouracil [300 mg/m(2)]). The Brief Fatigue Inventory (BFI), a measure that categorizes fatigue severity on a 0-10 scale, was administered weekly during treatment. Severe fatigue was defined as 7-10 on the "worst level of fatigue" item. Demographics, disease information, toxicities, and blood counts were collected. Descriptive statistics, repeated measure analysis of variance, and multiple regression were used to examine fatigue and its correlates.

RESULTS

Fatigue increased in 67% of patients during chemoradiation (CTX/XRT). The mean fatigue score increased from 3.16 before treatment to 4.62 at the end of treatment. A significant linear trend suggested that fatigue progressively got worse during CTX/XRT (F = 16.497, P < 0.001). However, 18% of patients experienced severe fatigue before CTX/XRT; this was predicted by uncontrolled pain (r(2) = 0.321; F = 16.52; P < 0.001). During CTX/XRT, uncontrolled diarrhea was the only predictor for increased fatigue (r(2) = 0.182; F = 7.77; P < 0.01). Approximately one-third of patients had severe fatigue, which impaired their function at the end of CTX/XRT.

CONCLUSIONS

Preoperative chemoradiation therapy for patients with rectal cancer was associated with progressive fatigue during therapy. Based on identified predictors for fatigue, more active pain management before CXT/XRT and bowel management during CTX/XRT might reduce cancer-related fatigue in these patients.

A fatigue clinic in a comprehensive cancer center: design and experiences

Cancer-related fatigue is now the most prevalent symptom of cancer, occurring in 60-90% of patients. Fatigue has been identified by cancer patients as a factor influencing functionality and quality of life. Our objectives in developing a fatigue specialty clinic at The University of Texas M. D. Anderson Cancer Center were to improve our patients' quality of life by decreasing fatigue; educate health care providers, patients, and patients' families about cancer-related fatigue; develop an appropriate clinical and diagnostic evaluation for this symptom; correlate objective measures of fatigue with its clinical evaluation; and develop innovative treatment plans for cancer-related fatigue. This article describes the general clinic design and operations and the preliminary analysis of the first 40 patients evaluated in the fatigue clinic.

Treatment advances for cocaine-induced ischemic stroke: focus on dihydropyridine-class calcium channel antagonists

OBJECTIVE

The authors reviewed the pathogenesis of cocaine-related cerebral ischemia, appraised current knowledge of its sequelae, and assessed the role of putative therapeutic agents, particularly dihydropyridine-class calcium channel antagonists.

METHOD

The authors performed an OVID-based literature review of all indexed journals between 1966 and 2000.

RESULTS

Cocaine abuse significantly increases the risk of ischemic stroke. The principal mechanism of cocaine-induced cerebral ischemia is vasospasm of large cranial arteries or within the cortical microvasculature. Increased levels of extracellular monoamines, particularly dopamine, mediate vasospasm. Neuroanatomical and labeling studies also have shown that dopamine-innervated neurons may regulate cerebral blood flow. Indeed, dopamine-rich brain regions appear to be relatively specific targets for cocaine-induced cerebral ischemia. Neuroimaging studies show that cocaine-induced hypoperfusion can persist even after 6 months of abstinence. Hypoperfusion can result in deficits on complex and simple psychomotor tasks but perhaps not on memory or attention. Severe cerebral ischemia can directly precipitate neuronal death and degradation, a condition exacerbated by liberation of the excitatory amino acid glutamate. Dihydropyridine-class calcium channel antagonists inhibit cocaine-mediated dopamine release on neurons involved in vasospasm and the control of cortical circulation. Other causes of cerebral ischemia include thrombogenesis and vasculitis. Although antithrombotic agents have potential in alleviating cocaine's neurotoxic effects, their use may be limited by the risk of spontaneous hemorrhage.

CONCLUSIONS

Cocaine abuse can result in stroke, neuroischemia, and cognitive deficits that can persist even after prolonged abstinence. Dihydropyridine-class calcium channel antagonists, such as isradipine, show promise as therapeutic agents for preventing cocaine-induced cerebral ischemia.

Combining ondansetron and naltrexone treats biological alcoholics: corroboration of self-reported drinking by serum carbohydrate deficient transferrin, a biomarker

BACKGROUND

Recently, we showed by using self-report that combining ondansetron (4 microg/kg twice a day) and naltrexone (25 mg twice a day) was effective at reducing drinking and increasing abstinence among early-onset alcoholics (EOAs), who are characterized by a range of antisocial behaviors and high biological and familial disease predisposition. Here, we investigated whether the self-reported differences in drinking would be corroborated by measurements of serum carbohydrate-deficient transferrin (CDT) level, a sensitive, reliable, and well-validated marker of transient alcohol consumption.

METHOD

An 8-week double-blind clinical trial was performed in which 20 EOAs were randomized to receive ondansetron (4 microg/kg twice a day) and naltrexone (25 mg twice a day) or placebo as an adjunct to weekly standardized cognitive behavioral therapy. Serum CDT was assessed at weeks 0 (baseline), 4, and 8.

RESULTS

Log serum CDT was significantly lower in the ondansetron and naltrexone group (group mean, 1.44 +/- 0.076) compared with the placebo group (group mean, 1.82 +/- 0.113), as evidenced by a main effect of group [F(1,15) = 7.2, p = 0.017; effect size = 0.32], visit [F(1,16) = 11.2, p = 0.004; effect size = 0.41], and an interaction between group and visit [F(1,16) = 27.54, p < 0.001; effect size = 0.63].

CONCLUSIONS

The combination of ondansetron plus naltrexone was superior to placebo at reducing serum CDT. This corroborated our self-reported drinking data and demonstrated that the medication combination is an effective treatment for EOAs.

Fingertip injuries

The family physician often provides the first and only medical intervention for fingertip injuries. Proper diagnosis and management of fingertip injuries are vital to maintaining proper function of the hand and preventing permanent disability. A subungual hematoma is a painful condition that involves bleeding beneath the nail, usually after trauma. Treatment requires subungual decompression, which is achieved by creating small holes in the nail. A nail bed laceration is treated by removing the nail and suturing the injured nail bed. Closed fractures of the distal phalanx may require reduction but usually are minimally displaced and stable, and can be splinted. Open or intra-articular fractures of the distal phalanx may warrant referral. Patients with mallet finger cannot extend the distal interphalangeal joint because of a disruption of the extensor mechanism. Radiographs help to differentiate between tendinous and bony mallet types. Most mallet finger injuries heal with six to eight weeks of splinting, but some require referral. Flexor digitorum profundus avulsion always requires referral. Dislocations of the distal interphalangeal joint are rare and usually occur dorsally.

Rapid clot formation and abnormal fibrin structure in a symptomatic patient taking fenfluramine--a case report

A 35-year-old woman experienced symptomatic calf pain while taking a combination of fenfluramine and phentermine. All symptoms resolved when the medications were stopped, but pain returned when fenfluramine was restarted. Laboratory evaluation revealed mild elevations of aspartate aminotransferase and lactate dehydrogenase and a remarkably shortened prothrombin time (6.3 seconds). Additional studies revealed that the clots were composed of very thin fibrin fibers. All laboratory abnormalities, including the abnormal fibrin structure, completely resolved when fenfluramin was stopped. Direct addition of fenfluramine or phentermine to normal plasma did not alter either coagulation kinetics or fibrin structure, supporting the concept that the induced changes may have originated at the hepatic level. Clots composed of thin fibers are much more resistant to fibrinolysis, and could potentially put such patients at risk for thrombotic complications. This is the first report of clotting abnormalities associated with fenfluramine use. Subsequent to its use in this patient, fenfluramine was removed from clinical use due to reports of acquired valvular heart disease.

Use of the lapidus bunionectomy in first ray insufficiency

Surgical management of first ray insufficiency in HAV or hallux limitus is crucial to long-term success. Although technically demanding, the Lapidus fusion serves to address the deformity at its apex and restores normal weight bearing to the foot. This arthrodesis offers predictable, durable results in addressing various first ray deformities and occupies an important place in the foot and ankle surgeon's armamentarium. The authors' technique is described herein for the interest of and evaluation by surgeons performing this procedure. As clinicians recognize the importance of addressing proximal components of the HAV deformity, the Lapidus and other procedures will likely see increased use in the surgical management of first ray deformities.

Age of onset as a discriminator between alcoholic subtypes in a treatment-seeking outpatient population

Subtyping alcoholics may provide a more accurate guide as to the course and character of the disease. Classifications of different ages of onset of problem drinking have so far resulted in categorical inconsistencies. In the past, hospital-based alcoholics have over-represented those most severely ill, and comprehensive evaluations of psychopathology for discriminating between alcoholic subtypes have been infrequent. In a heterogeneous treatment-seeking, outpatient, alcoholic population, we tested the hypothesis that age of onset represents a continuum of disease, and that greater severity of psychopathology is associated with lower ages of onset. Using a standard questionnaire, 253 male and female treatment-seeking alcoholics were stratified according to specific ages of onset: a) < 20 years; b) 20-25 years, and c) > 25 years. These age of onset groups were compared on alcohol severity and craving, family history, childhood behavior, personality, hostility, overt aggression, mood, and social functioning. Symptom severity and age of onset were negatively correlated, and the 20-25-year onset group usually had intermediate scores. The < 20 year onset group was characterized by greater severity of alcohol-related problems, family history, childhood behavioral problems, craving, hostility, antisocial traits, mood disturbance, and poor social functioning. Alcoholics with an earlier age of onset have relatively greater psychopathology than those of later onset. While the preponderance of psychopathology among those in the < 20-year onset group could be conceptualized as a clinical "subtype," such a characterization would not define an entirely homogeneous category. Yet, this clinical characterization would be clinically important if specific age of onset levels were found to be differentially sensitive to pharmacological and/or psychological treatments.

Combining ondansetron and naltrexone reduces craving among biologically predisposed alcoholics: preliminary clinical evidence

RATIONALE

Previously, we have reported that the combination of ondansetron (a 5-HT3 antagonist) and naltrexone (a mu opioid antagonist) appears to act synergistically at improving the drinking outcomes of early onset alcoholics (EOA). a subtype of alcoholic characterized by developing problem-drinking earlier, antisocial behaviors, high familial loading, and biological disease predisposition. Presumably, this medication combination counteracts the interaction between activated central 5-HT3 receptors and the endogenous opioid system during the mediation of alcohol-induced reward. We now hypothesize further that an important mechanism by which the combination diminishes alcohol consumption is through a reduction in craving.

OBJECTIVE

To determine whether the combination of naltrexone and ondansetron is superior to a placebo at reducing craving among EOA, and the relationship between craving and drinking behavior in both treatment groups.

METHODS

We conducted an 8-week double-blind placebo-controlled clinical trial in which 10 EOA were randomized to receive ondansetron (4 microg/kg b.i.d.) + naltrexone (25 mg b.i.d.) and 10 EOA had a placebo (total n=20) as an adjunct to weekly standardized group cognitive behavioral therapy. Craving was measured by using the obsessive compulsive drinking scale (OCDS).

RESULTS

Craving ratings were scored on four subscales which where derived empirically by principal component structure analysis of the OCDS. EOA who received the medication combination, compared with the placebo, had significantly lower scores on "automaticity of drinking" and "alcohol consumption ". Reduction in automaticity of drinking was correlated with self-reported drinking for only the medication combination group.

CONCLUSIONS

By reducing automaticity of drinking, the medication combination presumably decreased drinking salience and intensity. Larger scale studies testing these medications, both alone and together, among alcoholic subtypes are needed to establish and extend these promising findings.

Ductography: how to and what if?

Ductography of the breast is an underused procedure that often helps define the cause of unilateral, single-pore, spontaneous nipple discharge. Since nipple discharge may be caused by benign tumors, such as papillomas, or by carcinoma, such as ductal carcinoma in situ, identification of intraductal abnormalities with ductography is important. Further, diagnostic ductography and preoperative ductography help guide accurate surgical intervention. Without prior ductography, central duct excision may not result in removal of the abnormal ductal tissue or may result in removal of only a portion of the abnormal ductal system, causing the extent of disease to be effectively understaged. Once fundamental ductographic principles are learned, the procedure is easy to perform. If extravasation occurs, ductography is rescheduled for 7-14 days later. Elimination of air bubbles from the cannula, syringe, and extension tubing is vital. When reflux occurs, radiologists must be aware of a possible tumor in the distal-most duct. When ductal ectasia or fibrocystic changes are the cause of the discharge, conservative follow-up may be considered. Diagnostic radiologists who learn the technique of ductography and include it in their evaluation of nipple discharge will improve their interdisciplinary approach to this important sign of breast cancer.

Vitamin D deficiency among older women with and without disability

BACKGROUND

Vitamin D deficiency is associated with bone loss and bone fractures, and the identification of vulnerable populations is important to clinical practice and public health.

OBJECTIVE

The objectives of this study were to determine the prevalence of vitamin D deficiency and to examine associated risk factors for vitamin D deficiency in older women.

DESIGN

We measured serum concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1, 25(OH)(2)D], intact parathyroid hormone (PTH), osteocalcin, and ionized calcium in women aged >/=65 y who were participating in the Women's Health and Aging Study I, an observational study of women representing the approximately one-third most disabled women living in the community, and women aged 70-80 y who were participating in the Women's Health and Aging Study II, an observational study of women among the two-thirds least disabled women living in the community in Baltimore.

RESULTS

The women were classified into 4 domains of physical disability. Among 371 women with 0 or 1 domain of disability and 682 women with >/=2 domains of disability, 6.2% and 12.6%, respectively, had vitamin D deficiency [serum concentrations of 25(OH)D < 25 nmol/L]. In univariate analyses, risk factors for vitamin D deficiency included increasing age, black race, low educational level, high body mass index, high triceps skinfold thickness, increasing level of disability, winter season, and elevated creatinine concentration. In multivariate models, black race had a strong association with vitamin D deficiency when other risk factors were adjusted for.

CONCLUSIONS

Vitamin D deficiency, a preventable disorder, is a common and important public health problem for older disabled women living in the community; black women are at higher risk than are white women.

Integration of student-health physicians into U.S. medical schools and their affiliated teaching hospitals

PURPOSE

To determine whether physicians in the student health services (SHSs) at U.S. medical schools and their affiliated teaching hospitals, referred to here as academic medical centers (AMCs), have unique opportunities for integration into AMCs that do not exist for physician-faculty at SHSs on purely academic campuses.

METHOD

A survey of SHS offices at the 124 U.S. medical schools was conducted in the spring of 1999. The questionnaire asked about the reporting relationships of the SHS within the AMC, whether the student-health physicians had academic appointments within the AMC, and whether these physicians participated in the AMC's clinical services, administration, research, or teaching activities.

RESULTS

There were 116 (94%) responses (not all responses were complete and eight were excluded because their campuses offered no formal SHS). Approximately half of the SHSs (52/107, 49%) reported to their AMCs. Student-health physicians with career-track appointments were more likely to be found at SHSs reporting to AMCs (35/58, 60%) than at SHSs reporting solely to a division of student affairs (20/58, 34%). Having a career-track appointment increased the likelihood of the student-health physicians' attending on the wards (34/59, 58%), seeing private patients in an AMC's faculty practice (40/59, 68%), participating in administrative activities for an AMC (50/56, 89%), and participating in research activities (36/57, 63%).

CONCLUSIONS

Student health services that reported to their AMCs were more likely to have faculty with career-track appointments, and these appointments were more likely to result in the integration of student-health physicians into their AMC's clinical services, administration, and research activities. Career-track appointments, however, had no influence on whether teaching activities occurred within the SHS. Fully integrating student-health physicians into the AMC's activities enhances outcomes for both the SHS and its AMC.

Odorant molecular length: one aspect of the olfactory code

Organic acid odorants of differing carbon number produce systematically different spatial patterns of [(14)C]2-deoxyglucose uptake in the glomerular layer of the olfactory bulb. Because increasing carbon number correlates with progressive increases in several molecular features, including hydrophobicity, length, and volume, we determined which of these properties was most associated with systematic changes in the location of an anterior, dorsomedial module responding to fatty acids. We exposed groups of rats to two series of organic acids that each had the same number of carbons, but differed in their hydrocarbon structures. These straight-chained, branched, cyclic, and double-bonded molecules differed independently in hydrophobicity, length, and volume. The only molecular property that was strongly correlated with the location of the module was molecular length, suggesting that this molecular feature is the principal determinant of the chemotopic organization of glomeruli within the module. We also found that distinct hydrocarbon structures produced large differences in spatial patterns of 2-deoxyglucose uptake in posterior parts of the bulb. Even subtly distinct structural isomers evoked posterior responses that differed greatly. The odorant 2-methylbutyric acid evoked much greater uptake in the posterior bulb than did its structural isomer 3-methylbutyric acid (isovaleric acid). These data suggest that posterior portions of the bulb may encode specific steric features of odorant molecules and that some odorant features may have an inherent or acquired greater representation than do others.

Use of systemic agents in the treatment of acne vulgaris

Effective treatment of acne vulgaris can prevent emotional and physical scarring. Therapy varies according to the severity of the disease. Topical medication is generally adequate in clearing comedonal acne, while inflammatory acne usually requires the addition of oral medication. Systemic antibiotics are used most frequently and can be highly effective. Newer formulations of combined oral contraceptives are also helpful in modulating sebum production in the female patient. Severe nodulocystic acne that does not respond to topical retinoids and systemic antibiotics may be treated with isotretinoin. However, the side effect profile of this medication is extensive, and physicians should be well-versed in its potential adverse effects.

A transient assay for regulatory gene function in haemopoietic progenitor cells

This work aimed to provide a means of assaying directly the effects of transient expression of introduced genes on the survival, proliferation, lineage commitment and differentiation of haemopoietic progenitor cells. For this purpose, we have developed a system that allows isolation of productively transfected, mulitipotent haemopoietic cells within a few hours of the introduction of test genes. We have shown that FDCP-mix cells productively transfected with expression plasmids encoding green fluorescent protein (GFP) differentiate normally and retain colony-forming potential. We constructed an expression vector consisting of a bicistronic cassette in which a GFP marker gene and a test gene are driven from the same promoter. The vector design has been optimized for co-expression and the test gene was shown to be biologically active. The expression profile from a transiently transfected template under different growth conditions reveals that active expression continues for at least 2 d after transfection. The transient transfection of FDCP-mix cells with the vectors described provides a powerful tool for analysis of the immediate early effects of test gene overexpression during haemopoietic differentiation.

Ondansetron for reduction of drinking among biologically predisposed alcoholic patients: A randomized controlled trial

CONTEXT

Early-onset alcoholism differs from late-onset alcoholism by its association with greater serotonergic abnormality and antisocial behaviors. Thus, individuals with early-onset alcoholism may be responsive to treatment with a selective serotonergic agent.

OBJECTIVE

To test the hypothesis that drinking outcomes associated with early vs late-onset alcoholism are differentially improved by the selective 5-HT(3) (serotonin) antagonist ondansetron.

DESIGN

Double-blind, randomized, placebo-controlled clinical trial.

SETTINGS

University of Texas Health Science Center in Houston (April 1995-June 1998) and University of Texas Health Science Center in San Antonio (July 1998-December 1999).

PARTICIPANTS

A total of 321 patients with diagnosed alcoholism (mean age, 40.6 years; 70.5% male; 78.6% white) were enrolled, 271 of whom proceeded to randomization.

INTERVENTIONS

After 1 lead-in week of single-blind placebo, patients were randomly assigned to receive 11 weeks of treatment with ondansetron, 1 microg/kg (n = 67), 4 microg/kg (n = 77), or 16 microg/kg (n = 71) twice per day; or identical placebo (n = 56). All patients also participated in weekly standardized group cognitive behavioral therapy.

MAIN OUTCOME MEASURES

Self-reported alcohol consumption (drinks per day, drinks per drinking day, percentage of days abstinent, and total days abstinent per study week); and plasma carbohydrate deficient transferrin (CDT) level, an objective and sensitive marker of transient alcohol consumption.

RESULTS

Patients with early-onset alcoholism who received ondansetron (1, 4, and 16 microg/kg twice per day) compared with those who were administered placebo, had fewer drinks per day (1.89, 1.56, and 1.87 vs 3.30; P =.03, P =.01, and P =.02, respectively) and drinks per drinking day (4.75, 4.28, and 5.18 vs 6.90; P =.03, P =.004, and P =.03, respectively). Ondansetron, 4 microg/kg twice per day, was superior to placebo in increasing percentage of days abstinent (70.10 vs 50.20; P =.02) and total days abstinent per study week (6.74 vs 5.92; P =.03). Among patients with early-onset alcoholism, there was a significant difference in the mean log CDT ratio between those who received ondansetron (1 and 4 microg/kg twice per day) compared with those who received the placebo (-0.17 and -0.19 vs 0.12; P =.03 and P =.01, respectively).

CONCLUSION

Our results suggest that ondansetron (particularly the 4 microg/kg twice per day dosage) is an effective treatment for patients with early-onset alcoholism, presumably by ameliorating an underlying serotonergic abnormality. JAMA. 2000;284:963-971

Image-guided epidural injections

Epidural steroid injection is a safe outpatient procedure, which is performed best using image guidance in conjunction with epidurography. Using the techniques described earlier, complications are minimized, and serious complications can be avoided, in experienced hands. The author has performed several thousand procedures in an outpatient setting without any serious complications. Optimal safety and efficacy require an excellent working knowledge of the radiographic anatomy, and the imaging equipment used to perform these procedures. Several studies have demonstrated the difficulty and uncertainty of obtaining an accurate injection without imaging guidance. Radiologists who are well trained in the performance of image-guided percutaneous injection procedures are thus armed with the background to perform these procedures in a safe and efficacious manner. In addition, referral of these procedures to a third party (radiologist) without economic incentives reduces the potential abuse of self-referral--which may occur (or be suspected by payors) when the primary clinician recommends, and then performs, pain management procedures. The use of sedation to perform these procedures is unnecessary, and deep sedation may be dangerous when injections are performed in the vicinity of the spinal cord. The author's experience, which includes clinical feedback and formal trials, shows the technique described in this article to be performed safely without sedation in an outpatient setting, with a high success rate for alleviating pain symptoms. When properly performed, epidural steroid injections have a clinically established role in the management of neck and back pain.

Modular representations of odorants in the glomerular layer of the rat olfactory bulb and the effects of stimulus concentration

To study the mechanism whereby odorants are encoded in the nervous system, we studied the glomerular-layer activity patterns in the rat olfactory bulb evoked by closely related odorants from different chemical families. These odorants had a common straight-chain hydrocarbon structure, but differed systematically in their functional groups. Neural activity was mapped across the entire glomerular layer by using the ¿(14)C2-deoxyglucose method. Group responses were averaged and compared by using data matrices. The glomerular activity patterns that resulted from this analysis were comprised of modules. Unique combinations of modules were activated by each odorant, demonstrating what may be part of the neural code for odorants. Most of the modules were clustered together in the bulb, perhaps providing for enhanced contrast between related chemicals by means of lateral inhibition. We also determined whether changes in odorant concentration would affect spatial patterns of glomerular activity. Two odorants, pentanal and 2-hexanone, evoked different patterns at increased concentrations, with additional glomeruli being recruited at a great distance from glomeruli in which activity was evoked at lower concentrations. Humans report that both of these odorants change in perceived odor with increasing concentration. Three other odorants (pentanoic acid, methyl pentanoate, and pentanol) did not recruit new areas of glomerular activation with increasing concentration, and humans do not report a changed odor across concentrations of these odorants. The results suggest that changes in modular glomerular activity patterns could underlie altered odor perception across odorant concentrations, and they provide additional support for a combinatorial, spatially based code in the olfactory system.

Actin-containing sera from patients with adult respiratory distress syndrome are toxic to sheep pulmonary endothelial cells

Actin released from damaged cells after a variety of tissue injuries appears to be involved in multiple organ dysfunction syndrome. Under experimental conditions, when the quantity of actin present in plasma is made to exceed the protective capacity of the actin-scavenging mechanism, microembolism and pulmonary vascular angiopathy have been noted in rats. It remains to be determined whether this injury is a result of a direct toxic effect or occurs indirectly via platelet activation or fibrin interactions. We examined the effect of sera from patients with adult respiratory distress syndrome (ARDS), as well as G-actin added to normal serum, on the viability, morphology, and function of cultured sheep pulmonary artery endothelial cells (SPAEC). Both patient sera and normal sera to which actin was added were toxic in the cell culture model; this toxicity could be abrogated, at least partially, by preincubation with gelsolin, which is known to complex with actin. A significant portion of the toxicity of sera from patients with ARDS was sensitive to heat (56 degrees C), suggesting an important role of complement. Sera from patients with ARDS were shown to contain filaments of F-actin by immunoblot and rhodamine phalloidin staining after ultracentrifugation. Thus, saturation of the actin-scavenging system by addition of exogenous G-actin to plasma produces direct pulmonary endothelial cell injury. Furthermore, plasma from patients with ARDS secondary to bacterial pneumonia is toxic to SPAEC, and a small but significant contributory role of actin is apparent in these studies.