Showing papers by "University of Wisconsin-Madison published in 1991"
TL;DR: Adolescents whose parents are characterized as authoritarian score reasonably well on measures indexing obedience and conformity to the standards of adults but have relatively poorer self-conceptions than other youngsters, while adolescents from indulgent homes evidence a strong sense of self-confidence but report a higher frequency of substance abuse and school misconduct and are less engaged in school.
Abstract: In order to test Maccoby and Martin's revision of Baumrind's conceptual framework, the families of approximately 4,100 14-18-year-olds were classified into 1 of 4 groups (authoritative, authoritarian, indulgent, or neglectful) on the basis of the adolescents' ratings of their parents on 2 dimensions: acceptance/involvement and strictness/supervision. The youngsters were then contrasted along 4 sets of outcomes: psychosocial development, school achievement, internalized distress, and problem behavior. Results indicate that adolescents who characterize their parents as authoritative score highest on measures of psychosocial competence and lowest on measures of psychological and behavioral dysfunction; the reverse is true for adolescents who describe their parents as neglectful. Adolescents whose parents are characterized as authoritarian score reasonably well on measures indexing obedience and conformity to the standards of adults but have relatively poorer self-conceptions than other youngsters. In contrast, adolescents from indulgent homes evidence a strong sense of self-confidence but report a higher frequency of substance abuse and school misconduct and are less engaged in school. The results provide support for Maccoby and Martin's framework and indicate the need to distinguish between two types of "permissive" families: those that are indulgent and those that are neglectful.
2,324 citations
TL;DR: The findings indicate that despite its beneficial hemodynamic actions, long-term therapy with oral milrinone increases the morbidity and mortality of patients with severe chronic heart failure.
Abstract: Background. Milrinone, a phosphodiesterase inhibitor, enhances cardiac contractility by increasing intracellular levels of cyclic AMP, but the long-term effect of this type of positive inotropic agent on the survival of patients with chronic heart failure has not been determined. Methods. We randomly assigned 1088 patients with severe chronic heart failure (New York Heart Association class III or IV) and advanced left ventricular dysfunction to double-blind treatment with 40 mg of oral milrinone daily (561 patients) or placebo (527 patients). In addition, all patients received conventional therapy with digoxin, diuretics, and a converting-enzyme inhibitor throughout the trial. The median period of follow-up was 6.1 months (range, 1 day to 20 months). Results. As compared with placebo, milrinone therapy was associated with a 28 percent increase in mortality from all causes (95 percent confidence interval, 1 to 61 percent; P = 0.038) and a 34 percent increase in cardiovascular mortality (95 percent...
2,108 citations
28 Sep 1991
TL;DR: In this article, a control scheme for parallel-connected inverters in a standalone AC supply system is presented, which uses feedback of only those variables that can be measured locally at the inverter and does not need communication of control signals between the inverters.
Abstract: A scheme for controlling parallel-connected inverters in a standalone AC supply system is presented. This scheme is suitable for control of inverters in distributed source environments such as in isolated AC systems, large and distributed uninterruptible power supply (UPS) systems, photovoltaic systems connected to AC grids, and low-voltage DC power transmission meshes. A key feature of the control scheme is that it uses feedback of only those variables that can be measured locally at the inverter and does not need communication of control signals between the inverters. This is essential for the operation of large AC systems, where distances between inverters make communication impractical. It is also important in high-reliability UPS systems where system operation can be maintained in the face of a communication breakdown. Real and reactive power sharing between inverters can be achieved by controlling two independent quantities: the power angle and the fundamental inverter voltage magnitude. Simulation results are presented. >
1,550 citations
TL;DR: Prevention of binding between cell surface heparan sulfate and bFGF substantially reduces binding of fibroblast growth factor to its cell-surface receptors, blocks the ability of bF GF to support the growth of Swiss 3T3 fibroblasts, and induces terminal differentiation of MM14 skeletal muscle cells, which is normally repressed by fibro Blast growth factor.
Abstract: Basic fibroblast growth factor (bFGF) binds to heparan sulfate proteoglycans at the cell surface and to receptors with tyrosine kinase activity. Prevention of binding between cell surface heparan sulfate and bFGF (i) substantially reduces binding of fibroblast growth factor to its cell-surface receptors, (ii) blocks the ability of bFGF to support the growth of Swiss 3T3 fibroblasts, and (iii) induces terminal differentiation of MM14 skeletal muscle cells, which is normally repressed by fibroblast growth factor. These results indicate that cell surface heparan sulfate is directly involved in bFGF cell signaling.
1,516 citations
TL;DR: A new system for grading age-related maculopathy using stereoscopic 30 degrees color fundus photographs, standard circles printed on plastic to assess size and area, and a specially designed lightbox to allow better discrimination of subtle drusen is described and measures of reliability are reported.
1,172 citations
TL;DR: The authors discuss the assessment of the contribution of diagnostic imaging to the patient management process and presents a hierarchical model of efficacy as an organizing structure for appraisal of the literature on efficacy of imaging.
Abstract: The authors discuss the assessment of the contribution of diagnostic imaging to the patient management process. A hierarchical model of efficacy is presented as an organizing structure for appraisal of the literature on efficacy of imaging. Demonstration of efficacy at each lower level in this hierarchy is logically necessary, but not sufficient, to assure efficacy at higher levels. Level 1 concerns technical quality of the images; Level 2 addresses diagnostic ac curacy, sensitivity, and specificity associated with interpretation of the images. Next, Level 3 focuses on whether the information produces change in the referring physician's diagnostic thinking. Such a change is a logical prerequisite for Level 4 efficacy, which concerns effect on the patient management plan. Level 5 efficacy studies measure (or compute) effect of the information on patient outcomes. Finally, at Level 6, analyses examine societal costs and benefits of a diagnostic imaging technology. The pioneering contributions of Dr. Lee B. ...
1,092 citations
TL;DR: In this article, the authors show that advertising executional cues can influence communication effectiveness, and that communication effectiveness is in part driven by consumer behavior, which is similar to our findings.
Abstract: Considerable research suggests that advertising executional cues can influence communication effectiveness. Related research indicates that communication effectiveness is in part driven by consumer...
1,066 citations
TL;DR: In this article, a commercially available instrument for rapidly determining LAI and foliage inclination information from “fisheye” measurements of light interception is presented. But the instrument's estimates of LAI are compared with direct measurements in soybean [Glycine max (L.) Merr], winter wheat (Triticum aestivum L.), and prairie grass.
Abstract: Leaf area index (LAI) and leaf angle distribution are widely used indices of vegetative canopy structure that are difficult to measure directly. This study was conducted to test a commercially available instrument for rapidly determining LAI and foliage inclination information from “fisheye” measurements of light interception. The instrument's estimates of LAI are compared with direct measurements in soybean [Glycine max (L.) Merr.], winter wheat (Triticum aestivum L.), and prairie grass. The dominant grass species in the plots were Indian grass [Sorghastrum nutans (L.) Nash], switchgrass (Panicum virgatum L.), and big bluestem (Andropogon gerardii Vitman). The instrument's LAI resolution was better than 3%, and its LAI error was generally less than 15%. Variations in sky brightness patterns caused variations in LAI estimates in winter wheat of less than 10%, and the presence of direct solar radiation increased LAI errors to more than 30% in canopies of differing species and LAI. In the presence of gaps in the canopy, the sensor's azimuthal view should be reduced. A simple test indicates if a canopy's gaps are significant.
897 citations
854 citations
TL;DR: In this article, the authors examined the changes organizations undertook in response to a major environmental change and provided an empirical test of Hannan and Freeman's theory of structural inertia in the context of organizational change.
Abstract: This study provides an empirical test of Hannan and Freeman's theory of structural inertia. We examined the changes organizations undertook in response to a major environmental change. In addition,...
844 citations
TL;DR: Depressed subjects had less left-sided activation (i.e., more alpha activity) than did normal control subjects, interpreted as indicating a deficit in approach mechanisms in depressed subjects.
Abstract: Baseline resting electroencephalogram activity was recorded with 3 different reference montages from 15 clinically depressed and 13 control subjects. Power in all frequency bands was extracted by fast Fourier transformation. There was a significant Group X Hemisphere interaction in the mid-frontal region, for the alpha band power only. Depressed subjects had less left-sided activation (i.e., more alpha activity) than did normal control subjects. This pattern of diminished left-sided frontal activation is interpreted as indicating a deficit in approach mechanisms in depressed subjects.
TL;DR: The authors review the methods used to present visual, auditory, and modified tactile information to the skin and discuss present and potential future applications of sensory substitution, including tactile vision substitution (TVS), tactile auditory substitution, and remote tactile sensing or feedback (teletouch).
Abstract: Sensory substitution systems provide their users with environmental information through a human sensory channel (eye, ear, or skin) different from that normally used or with the information processed in some useful way. The authors review the methods used to present visual, auditory, and modified tactile information to the skin and discuss present and potential future applications of sensory substitution, including tactile vision substitution (TVS), tactile auditory substitution, and remote tactile sensing or feedback (teletouch). The relevant sensory physiology of the skin, including the mechanisms of normal touch and the mechanisms and sensations associated with electrical stimulation of the skin using surface electrodes (electrotactile, or electrocutaneous, stimulation), is reviewed. The information-processing ability of the tactile sense and its relevance to sensory substitution is briefly summarized. The limitations of current tactile display technologies are discussed, and areas requiring further research for sensory substitution systems to become more practical are suggested. >
TL;DR: It is concluded that use of 2% chlorhexidine, rather than 10% povidone-iodine or 70% alcohol, for cutaneous disinfection before insertion of an intravascular device and for post-insertion site care can substantially reduce the incidence of device-related infection.
TL;DR: The apparent optical depth (OOP) method as mentioned in this paper is a procedure for analyzing the absorption lines of an ionized gas toward HD 64760, where the absorption-line data are directly converted into a form that provides direct scientific interpretations of the physical conditions in the interstellar absorbing medium as a function of velocity.
Abstract: Attention is given to the apparent optical depth method, a procedure for analyzing interstellar absorption lines. Observed absorption-line profiles are converted into profiles of apparent optical depth, and apparent column density per unit velocity. By comparing the latter for a given interstellar species having two or more absorption lines which differ in the product, the presence or absence of unresolved saturated structure in the profiles can be directly inferred. The method is illustrated using absorption-line data from the IUE satellite for the highly ionized gas toward HD 64760. Additional illustrations and a study of the method's accuracy are provided through a series of numerical simulations of multicomponent interstellar absorption situations. The method is compared to the standard growth curve method for deriving interstellar column densities. The principal value of the apparent optical depth method is that the absorption-line data are directly converted into a form that provides for direct scientific interpretations of the physical conditions in the interstellar absorbing medium as a function of velocity.
TL;DR: In this paper, a method for the selection of a set of sensor locations from a larger candidate set for the purpose of on-orbit identification and correlation of large space structures is presented.
Abstract: A method is presented for the selection of a set of sensor locations from a larger candidate set for the purpose of on-orbit identification and correlation of Large Space Structures. The method ranks the candidate sensor locations according to their contribution to the linear independence of the target modal partitions. In an iterative maner, the locations which do not contribute significantly are removed. The final sensor configuration tends to maximize determinant of the corresponding Fisher Information Matrix.
TL;DR: Multivariate analyses showed both sex (women) and age (older) to be significant and independent predictors of poorer visual acuity.
TL;DR: The model successfully showed dynamic annual carbon partitioning controlled by water and nitrogen limitations, and showed simulated leaf area index ranging from 4.5 for a control stand at Missoula, to 11 for a fertilized stand at Madison, with Year 50 stem carbon biomasses.
Abstract: A new version of the ecosystem process model FOREST-BGC is presented that uses stand water and nitrogen limitations to alter the leaf/root/stem carbon allocation fraction dynamically at each annual iteration. Water deficit is defined by integrating a daily soil water deficit fraction annually. Current nitrogen limitation is defined relative to a hypothetical optimum foliar N pool, computed as maximum leaf area index multiplied by maximum leaf nitrogen concentration. Decreasing availability of water or nitrogen, or both, reduces the leaf/root carbon partitioning ratio. Leaf and root N concentrations, and maximum leaf photosynthetic capacity are also redefined annually as functions of nitrogen availability. Test simulations for hypothetical coniferous forests were performed for Madison, WI and Missoula, MT, and showed simulated leaf area index ranging from 4.5 for a control stand at Missoula, to 11 for a fertilized stand at Madison, with Year 50 stem carbon biomasses of 31 and 128 Mg ha(-1), respectively. Total nitrogen incorporated into new tissue ranged from 34 kg ha(-1) year(-1) for the unfertilized Missoula stand, to 109 kg ha(-1) year(-1) for the fertilized Madison stand. The model successfully showed dynamic annual carbon partitioning controlled by water and nitrogen limitations.
TL;DR: Results indicate that slo encodes a structural component of Ca(2+)- activated K+ channels, similar to voltage-activated K+ channel polypeptides in discrete domains known to be essential for function.
Abstract: Calcium-activated potassium channels mediate many biologically important functions in electrically excitable cells. Despite recent progress in the molecular analysis of voltage-activated K+ channels, Ca(2+)-activated K+ channels have not been similarly characterized. The Drosophila slowpoke (slo) locus, mutations of which specifically abolish a Ca(2+)-activated K+ current in muscles and neurons, provides an opportunity for molecular characterization of these channels. Genomic and complementary DNA clones from the slo locus were isolated and sequenced. The polypeptide predicted by slo is similar to voltage-activated K+ channel polypeptides in discrete domains known to be essential for function. Thus, these results indicate that slo encodes a structural component of Ca(2+)-activated K+ channels.
TL;DR: Computer simulation is used to compare the statistical properties of several methods that have been proposed for estimating the evolutionary correlation between two continuous traits, and to define alternative evolutionary correlations that may be of interest.
Abstract: We use computer simulation to compare the statistical properties of several methods that have been proposed for estimating the evolutionary correlation between two continuous traits, and define alternative evolutionary correlations that may be of interest. We focus on Felsenstein's (1985) method and some variations of it and on several "minimum evolution" methods (of which the procedure of Huey and Bennett (I9871 is a special case), as compared with a nonphylogenetic correlation. The last, a simple correlation of trait values across the tips of a phylogeny, virtually always yields inflated Type I error rates, relatively low power, and relatively poor estimates of evolutionary correlations. We therefore cannot recommend its use. In contrast, Felsenstein's (1 985) method yields acceptable significance tests, high power, and good estimates of what we term the input correlation and the standardized realized evolutionary correlation, given complete phylo- genetic information and knowledge of the rate and mode of character change (e.g., gradual and proportional to time ("Brownian motion") or punctuational, with change only at speciation events). Inaccurate branch length information may affect any method adversely, but only rarely does it cause Felsenstein's (1985) method to perform worse than do the others tested. Other proposed methods generally yield inflated Type I error rates and have lower power. However, certain min- imum evolution methods (although not the specific procedure used by Huey and Bennett (1987)) often provide more accurate estimates of what we term the unstandardized realized evolutionary correlation, and their use is recommended when estimation of this correlation is desired. We also demonstrate how correct Type I error rates can be obtained for any method by reference to an empirical null distribution derived from computer simulations, and provide practical suggestions on choosing an analytical method, based both on the evolutionary correlation of interest and on the availability of branch lengths and knowledge of the model of evolutionary change appropriate for the characters being analyzed. Computer programs that implement the various methods and that will simulate (correlated) character evolution along a known phylogeny are available from the authors on request. These programs can be used to test the effectiveness of any new methods that might be proposed, and to check the generality of our conclusions with regard to other phylogenies.
TL;DR: The results indicate that transfer of the dystrophin gene into the my ofibres of DMD patients could be beneficial, but a larger number of genetically modified myofibres will be necessary for clinical efficacy.
Abstract: DUCHENNE'S muscular dystrophy (DMD), which affects one in 3,500 males, causes progressive myopathy of skeletal and cardiac muscles and premature death1. One approach to treatment would be to introduce the normal dystrophin gene into diseased muscle cells. When pure plasmid DNA is injected into rodent skeletal2 or cardiac muscle3–5, the cells express reporter genes. We now show that a 12-kilobase full-length human dystrophin complemen-tary DNA gene and a 6.3-kilobase Becker-like gene6 can be expressed in cultured cells and in vivo. When the human dystrophin expression plasmids are injected intramuscularly into dystrophin-deficient mdx mice, the human dystrophin proteins are present in the cytoplasm and sarcolemma of ∼1% of the myofibres. Myofibres expressing human dystrophin contain an increased proportion of peripheral nuclei. The results indicate that transfer of the dystrophin gene into the myofibres of DMD patients could be beneficial, but a larger number of genetically modified myofibres will be necessary for clinical efficacy.
TL;DR: The genetics and biochemistry of a large, newly discovered family of calcium‐dependent, pore‐forming cytotoxins (RTX toxins) produced by different genera of the Enterobacteriaceae and Pasteurellaceae are discussed and emerging questions about the role of cytolysins in pathogenesis are presented.
Abstract: A great deal is known about the structure, function and metabolic effects of enzymatic bacterial toxins such as the diphtheria, pertussis and cholera toxins. By comparison, our understanding of the pore-forming, cytolytic toxins, particularly those produced by Gram-negative bacterial pathogens, is far less complete. The genetics and biochemistry of a large, newly discovered family of calcium-dependent, pore-forming cytotoxins (RTX toxins) produced by different genera of the Enterobacteriaceae and Pasteurellaceae are discussed in this review. This toxin family is especially noteworthy because the individual toxins often exhibit different cell- and host-specificity. A brief review is also included of two ancestrally unrelated groups of calcium-independent, pore-forming toxins, the haemolysins produced by Proteus mirabilis and Serratia marcescens and the aerolysins secreted by species of Aeromonas. Their structure and function are contrasted with those of the RTX family members. Emerging questions about the role of cytolysins in pathogenesis are presented. Perhaps the most important issue raised is whether or not less attention should be paid to the lytic capacity of these cytotoxins, with more energy being devoted to the understanding of their non-lytic inhibitory activities against host cells.
TL;DR: The results indicate that species allocate resources towards a high photosynthetic assimilation rate for a brief time, or provide resistant physical structure that results in a lower rate of carbon assimilation over a longer time, but not both.
Abstract: The relationships between resource availability, plant succession, and species' life history traits are often considered key to understanding variation among species and communities. Leaf lifespan is one trait important in this regard. We observed that leaf lifespan varies 30-fold among 23 species from natural and disturbed communities within a 1-km radius in the northern Amazon basin, near San Carlos de Rio Negro, Venezuela. Moreover, leaf lifespan was highly correlated with a number of important leaf structural and functional characterisues. Stomatal conductance to water vapor (g) and both mass and area-based net photosynthesis decreased with increasing leaf lifespan (r2=0.74, 0.91 and 0.75, respectively). Specific leaf area (SLA) also decreased with increasing leaf lifespan (r2=0.78), while leaf toughness increased (r2=0.62). Correlations between leaf lifespan and leaf nitrogen and phosphorus concentrations were moderate on a weight basis and not significant on an area basis. On an absolute basis, changes in SLA, net photosynthesis and leaf chemistry were large as leaf lifespan varied from 1.5 to 12 months, but such changes were small as leaf lifespan increased from 1 to 5 years. Mass-based net photosynthesis (A/mass) was highly correlated with SLA (r2=0.90) and mass-based leaf nitrogen (N/mass) (r2=0.85), but area-based net photosynthesis (A/area) was not well correlated with any index of leaf structure or chemistry including N/area. Overall, these results indicate that species allocate resources towards a high photosynthetic assimilation rate for a brief time, or provide resistant physical structure that results in a lower rate of carbon assimilation over a longer time, but not both.
TL;DR: Limited evidence indicates frequency of lipid feeding and physical form of oil (free oil vs. oilseed), and heat treatment of oilseeds has relatively little influence on modification of milk fat.
TL;DR: The evidence leading to the suggestion that the free pool of one of these proteins, hsp70, serves as a cellular thermometer that regulates the expression of all heat shock proteins is reviewed.
TL;DR: Ss reported their standards for how they should respond and how they would respond in contact situations with Black people (Study 1) and homosexual men (Study 2) and their affective consequences associated with should-would discrepancies as mentioned in this paper.
Abstract: Ss reported their standards for how they should respond and how they would respond in contact situations with Black people (Study 1) and homosexual men (Study 2). Interest centered on the affective consequences associated with should-would discrepancies
TL;DR: In this article, a review and synthesis of information available in the literature on sediment interactions with submersed macrophyte growth and community dynamics is presented, with an emphasis on factors affecting sediment nutrient availability.
TL;DR: Some C pneumoniae antibody titers, although not diagnostic of chlamydial infection by present criteria, probably represent acute reinfection or ongoing chronic infection.
Abstract: Objective. —To study the clinical characteristics of respiratory tract illness caused by Chlamydia pneumoniae . Design. —Prospective clinical, bacteriologic, and serologic study. Secondarily, a matched comparison of patients with and without evidence of C pneumoniae infection (serologic titers ≥1:64 and Setting. —Four primary care (family practice) clinics in Madison, Wis, and nearby towns. Patients. —The study included 365 white males and females (mean age, 34.2 years). Main Outcome Measures. —Association of acute C pneumoniae infection with signs and symptoms of respiratory illness and the relationship of C pneumoniae antibody titer with wheezing at the time of enrollment in the study, and with the diagnosis of asthmatic bronchitis. Results. —Nine (47%) of 19 patients with acute C pneumoniae infection had bronchospasm during respiratory illness, and there was a strong quantitative association of C pneumoniae titer with wheezing at the time of enrollment in the study ( P =.01). In the matched study, C pneumoniae antibody was significantly associated with asthmatic bronchitis after, but not before, respiratory illness (odds ratio, 7.2; 95% confidence interval, 2.2 to 23.4). Four infected patients had newly diagnosed asthma after illness, and four others had exacerbation of previously diagnosed asthma. There was no serologic evidence of coexisting Mycoplasma pneumoniae, Chlamydia trachomatis , or respiratory viral infection in 96% of patients with asthmatic bronchitis and asthma. Conclusions. —Some Cpneumoniae antibody titers, although not diagnostic of chlamydial infection by present criteria, probably represent acute reinfection or ongoing chronic infection. Repeated or prolonged exposure to C pneumoniae may have a causal association with wheezing, asthmatic bronchitis, and asthma. ( JAMA . 1991;266:225-230)
TL;DR: The comparison of present and ideal self-ratings supported the hypothesis that with age, individuals achieve a closer fit between their ideal and their actual self-perceptions.
Abstract: Young, middle-aged, and elderly adults (N = 308) evaluated themselves on 6 dimensions of psychological well-being according to present, past, future, and ideal self-assessments. Young and middle-aged adults saw considerable improvement in themselves from the past to the present on all dimensions of well-being. The elderly, however, indicated largely a perception of stability with prior levels of functioning. Future ratings showed that the 2 younger groups expected continued gains in the years ahead, whereas the oldest respondents foresaw decline on most aspects of well-being. The comparison of present and ideal self-ratings supported (cross-sectionally) the hypothesis that with age, individuals achieve a closer fit between their ideal and their actual self-perceptions.
TL;DR: This work presents one method based on stable isotope analysis in human tissues and discusses its contributions, and discusses several potential sources of variation including sex, age, nutritional status, among others.
Abstract: Extracting nutrients is of upmost importance to the sur- vival of any individual or species. One of the distinguishing characteristics of the order Primates is the vast range of nutritional adaptations it exhibits. Within our own species all manner of adaptations are practiced and it has been a major focus of research to determine when and where these various patterns originated. We present one method based on stable isotope analysis in human tissues and discuss its contributions. The ratios of l3C/''C and 15N/14N vary among various pools (i.e., the atmosphere, the oceans, plant communities, trophic levels). These differences are transferred to humans via the foods they eat. The major differences in carbon occur between two photosynthetic pathways (C3 and C4), which in the New World permits tracing the introduction of maize (a C4 plant) and in Asia permits tracing the introduction of millet (also a C4 plant). The marine and terrestrial systems have distinctive isotope ratios of both carbon and nitrogen. Thus, the dependence on marine resources has been traced throughout several areas of the New and Old Worlds. We discuss several potential sources of variation including sex, age, nutritional status, among others. We conclude with some suggestions for future research.
TL;DR: In vivo studies show that scavenger-receptor ligands greatly inhibit hepatic uptake of lipid IVA in mice, and scavenger receptors expressed on macrophages may have an important role in the clearance and detoxification of endotoxin in animals.
Abstract: Lipid A is the active moiety of lipopolysaccharide (LPS, also referred to as endotoxin), a surface component of Gram-negative bacteria that stimulates macrophage activation and causes endotoxic shock. Macrophages can bind, internalize and partially degrade LPS, lipid A and its bioactive precursor, lipid IVA. We report here that lipid IVA binding and subsequent metabolism to a less active form by macrophage-like RAW 264.7 cells is mediated by the macrophage scavenger receptor. Scavenger-receptor ligands inhibit lipid IVA binding to, and metabolism by, RAW cells, and lipid IVA binds to type I and type II bovine scavenger receptors on transfected Chinese hamster ovary cells. Although in vitro competition studies with RAW cells indicate that scavenger receptor binding is not involved in LPS or lipid IVA-induced stimulation of macrophages, in vivo studies show that scavenger-receptor ligands greatly inhibit hepatic uptake of lipid IVA in mice. Thus, scavenger receptors expressed on macrophages may have an important role in the clearance and detoxification of endotoxin in animals.