Standardised images of novel objects created with generative adversarial networks

An enduring question in cognitive science is how perceptually novel objects are processed. Addressing this issue has been limited by the absence of a standardised set of object-like stimuli that appear realistic, but cannot possibly have been previously encountered. To this end, we created a dataset, at the core of which are images of 400 perceptually novel objects. These stimuli were created using Generative Adversarial Networks that integrated features of everyday stimuli to produce a set of synthetic objects that appear entirely plausible, yet do not in fact exist. We curated an accompanying dataset of 400 familiar stimuli, which were matched in terms of size, contrast, luminance, and colourfulness. For each object, we quantified their key visual properties (edge density, entropy, symmetry, complexity, and spectral signatures). We also confirmed that adult observers (N = 390) perceive the novel objects to be less familiar, yet similarly engaging, relative to the familiar objects. This dataset serves as an open resource to facilitate future studies on visual perception.

Dysfunctional decision-making in binge-eating disorder: A meta-analysis and systematic review

Binge-Eating Disorder (BED) involves anticipatory craving and urges, subjective loss-of-control during binge-eating episodes, and post-feeding psychological distress and guilt. Evidence indicates neurocognitive dysfunctions contribute to BED onset, maintenance, and treatment response. However, an integrated understanding of how cognitive processes underpin BED symptomology is lacking. We utilised a multi-stage decision-making model defining ten cognitive processes underpinning Preference Formation, Choice Implementation, Feedback Processing, and Flexibility/Shifting, to comprehensively review research published since 2013. We used preregistered PICOS criteria to assess 1966 articles identified from PubMed, PsycInfo, and Scopus database searches. This yielded 50 studies reporting behavioural cognitive tasks outcomes, comparing individuals with BED to controls with normal and higher weight. Meta-analyses revealed a unique profile of cognitive dysfunctions that spanned all decision-making stages. Significant deficits were evident in Uncertainty Evaluation, Attentional Inhibition, Choice Consistency, and Cognitive Flexibility/Set-shifting. We propose a novel model of dysfunctional decision-making processes in BED and describe their role in binge-eating behaviour. We further highlight the potential for cognitive interventions to target these processes and address the significant treatment gap in BED.

Salt-Tolerant Halophyte Rhizosphere Bacteria Stimulate Growth of Alfalfa in Salty Soil

Halophytes are plants that are adapted to grow in saline soils, and have been widely studied for their physiological and molecular characteristics, but little is known about their associated microbiomes. Bacteria were isolated from the rhizosphere and as root endophytes of Salicornia rubra, Sarcocornia utahensis, and Allenrolfea occidentalis, three native Utah halophytes. A total of 41 independent isolates were identified by 16S rRNA gene sequencing analysis. Isolates were tested for maximum salt tolerance, and some were able to grow in the presence of up to 4 M NaCl. Pigmentation, Gram stain characteristics, optimal temperature for growth, and biofilm formation of each isolate aided in species identification. Some variation in the bacterial population was observed in samples collected at different times of the year, while most of the genera were present regardless of the sampling time. Halomonas, Bacillus, and Kushneria species were consistently isolated both from the soil and as endophytes from roots of all three plant species at all collection times. Non-culturable bacterial species were analyzed by Illumina DNA sequencing. The most commonly identified bacteria were from several phyla commonly found in soil or extreme environments: Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, and Gamma- and Delta-Proteobacteria. Isolates were tested for the ability to stimulate growth of alfalfa under saline conditions. This screening led to the identification of one Halomonas and one Bacillus isolate that, when used to inoculate young alfalfa seedlings, stimulate plant growth in the presence of 1% NaCl, a level that significantly inhibits growth of uninoculated plants. The same bacteria used in the inoculation were recovered from surface sterilized alfalfa roots, indicating the ability of the inoculum to become established as an endophyte. The results with these isolates have exciting promise for enhancing the growth of inoculated alfalfa in salty soil.

Biomaterial surface chemistry dictates adherent monocyte/macrophage cytokine expression in vitro

An in vitro human monocyte culture system was used to determine whether adherent monocyte/macrophage cytokine production was influenced by material surface chemistry. A polyethylene terephthalate (PET) base surface was modified by photograft copolymerization to yield hydrophobic, hydrophilic, anionic and cationic surfaces. Freshly isolated human monocytes were cultured onto the surfaces for periods up to 10 days in the presence or absence of interleukin-4 (IL-4). Semi-quantitative RT-PCR analysis on days 3, 7 and 10 of cell culture revealed that interleukin-10 (IL-10) expression significantly increased in cells adherent to the hydrophilic and anionic surfaces but significantly decreased in the cationic surface adherent monocytes/macrophages. Conversely, interleukin-8 (IL-8) expression was significantly decreased in cells adherent to the hydrophilic and anionic surfaces. Further analysis revealed that the hydrophilic and anionic surfaces inhibited monocyte adhesion and IL-4-mediated macrophage fusion into foreign body giant cells (FBGCs). Therefore, hydrophilic and anionic surfaces promote an anti-inflammatory type of response by dictating selective cytokine production by biomaterial adherent monocytes and macrophages. These studies contribute information necessary to enhance our understanding of biocompatibility to be used to improve the in vivo lifetime of implanted medical devices and prostheses.

Influence of biomaterial surface chemistry on the apoptosis of adherent cells

A common component of the foreign-body response to implanted materials is the presence of adherent macrophages that fuse to form foreign-body giant cells (FBGCs). These multinucleated cells have been shown to concentrate the phagocytic and degradative properties of macrophages at the implant surface and are responsible for the damage and failure of the implant. Therefore, the modulation of the presence or actions of macrophages and FBGCs at the material-tissue interface is an extensive area of recent investigations. A possible mechanism to achieve this is through the induction of the apoptosis of adherent macrophages, which results in no inflammatory consequence. We hypothesize that the induction of the apoptosis of biomaterial adherent cells can be influenced by the chemistry of the surface of adhesion. Herein, we demonstrate that surfaces displaying hydrophilic and anionic chemistries induce apoptosis of adherent macrophages at a higher magnitude than hydrophobic or cationic surfaces. Additionally, the level of apoptosis for a given surface is inversely related to that surface's ability to promote the fusion of macrophages into FBGCs. This suggests that macrophages fuse into FBGCs to escape apoptosis.

Prevention of monocyte adhesion and inflammatory cytokine production during blood platelet storage: an in vitro model with implications for transfusion practice

A novel platelet additive solution [ThromboSoltrade mark (TS)] was designed to allow extended refrigerated platelet storage. It has been shown to preserve platelet function and prevent cytokine accumulation in platelet concentrates stored for up to 9 days. It consists of amiloride, adenosine, sodium nitroprusside, dipyridamole, quinacrine, and ticlopidine. We hypothesized that the cytokine inhibition may be due to prevention of monocyte (MC) adhesion and activation on the surfaces of platelet storage bag plastic polymers. In an in vitro model, we incubated purified peripheral blood MCs on discs of polyolefin and polyvinylchloride from platelet storage bags, and on polystyrene, in the presence of TS for up to 7 days. We found that after incubation with TS, adherent MC numbers were decreased by >80-95% compared with controls on all surfaces examined. Levels of cytokines [interleukin (IL)-1beta, IL-1RA, IL-6, IL-8, and tumor necrosis factor-alpha] were low in wells with TS but rose progressively in the controls during incubation. Amiloride alone had similar effects on adhesion and cytokine release as the complete TS preparation. Removing amiloride from TS abrogated these effects. These findings suggest an important role for TS and amiloride in monocyte function, and have implications for the development of agents designed for prolonged platelet storage.

Correlation of cytokine elaboration with mononuclear cell adhesion to platelet storage bag plastic polymers: a pilot study

The basis for many febrile nonhemolytic transfusion reactions associated with platelet transfusion therapy is cytokine elaboration and accumulation in the storage bag, which correlate with the leukocyte content and the length of platelet storage. We propose that a possible additional variable in the elaboration and accumulation of cytokines is the differential adhesion of mononuclear cells to the plastic substrate of the platelet storage bag. We hypothesize that mononuclear cell adhesion-induced cytokine release is greater in random-donor platelet bags composed of the polyolefin polymer compared to the single-donor apheresis platelet bags composed of the polyvinyl chloride polymer with the tri-(2-ethylhexyl) trimellitate (TEHTM) plasticizer. For four blood donors, we demonstrate preferential mononuclear cell adhesion, in vitro, to discs of polyolefin polymer versus discs of polyvinyl chloride polymer with the TEHTM plasticizer. Scanning electron microscopy corroborates this. In addition, proinflammatory cytokine (interleukin 1beta [IL-1beta] and tumor necrosis factor alpha [TNF-alpha]) levels are greater in culture wells containing discs of polyolefin polymer than in those containing discs of polyvinyl chloride polymer with the TEHTM plasticizer, and even more so in storage bags containing polyolefin polymer versus polyvinyl chloride polymer with the TEHTM plasticizer (IL-1beta, TNF-alpha, IL-6, and IL-8). This study suggests, for the first time, that differential plastic substrate mononuclear cell adhesion may contribute to cytokine release during platelet storage. This may represent an additional variable in the pathophysiology of febrile nonhemolytic transfusion reactions in patients receiving stored platelet units.

Spatial regulation and surface chemistry control of monocyte/macrophage adhesion and foreign body giant cell formation by photochemically micropatterned surfaces

A long-standing goal of biomedical device development has been the generation of specific, desired host blood and tissue responses. An approach to meeting this design criteria is precise surface modification that creates micropatterns of distinct physicochemical character to direct cell adhesion and behavior. For this study, poly(ethylene terephthalate) films were coated with poly(benzyl N, N-diethyldithiocarbamate-co-styrene) and sequentially exposed to monomer solutions for photoirradiation. A photomask was placed over different regions to generate micropatterned surfaces with graft polymer stripes of three distinct ionic characters. Human monocytes were cultured on these surfaces to ascertain whether adhesion and fusion of monocytes/macrophages could be controlled. Nonionic polyacrylamide greatly inhibited adhesion and induced clumping of the few monocytes that did adhere. Macrophage adhesion and spreading led to high degrees of interleukin-13 induced foreign body giant cell formation on both the anionic poly(acrylic acid), sodium salt, and benzyl N,N-diethyldithiocarbamate portions of the culture surface. In spite of the highest observed levels of monocyte/macrophage adhesion on cationic poly(dimethylaminopropylacrylamide), methiodide, the adherent cells were not competent to undergo fusion to form foreign body giant cells. These results suggest that inflammatory cell responses may be spatially controlled in a manner that may be ultimately exploited to improve the biocompatibility of medical devices.

Disruption of filamentous actin inhibits human macrophage fusion

The foreign body reaction to implanted biomaterials, characterized by the presence of macrophages and foreign body giant cells (FBGC), can result in structural and functional failure of the implant. Recently, we have shown that interleukin-4 and interleukin-13 can independently induce human macrophage fusion to form FBGC via a macrophage mannose receptor (MR) -mediated pathway. The MR is believed to mediate both endocytosis of glycoproteins and phagocytosis of microorganisms, which bear terminal mannose, fucose, N-acetylglucosamine, or glucose residues. Polarization of microfilaments to closely apposed macrophage membranes as observed with fluorescence confocal microscopy led us to ask whether MR-mediated fusion occurred via a filamentous actin-dependent pathway. Cytochalasins B and D and latrunculin-A, agents that disrupt microfilaments, inhibited macrophage fusion in a concentration-dependent manner. The concentrations of cytochalasins D and B that inhibited fusion did not significantly decrease macrophage adhesion, spreading, or motility but did inhibit internalization of Candida albicans during interleukin-13-enhanced, MR-mediated phagocytosis. Very low concentrations of cytochalasin B (< 2 microM) induced a slight enhancement of macrophage fusion. Taken together, the results of this study suggest that cytokine-induced, MR-mediated macrophage fusion requires an intact F-actin cytoskeleton and that the mechanism of fusion is similar to phagocytosis.--DeFife, K. M., Jenney, C. R., Colton, E., Anderson, J. M. Disruption of filamentous actin inhibits human macrophage fusion.

Cytoskeletal and adhesive structural polarizations accompany IL-13-induced human macrophage fusion

During the inflammatory response to an implanted biomaterial, monocytes undergo a striking phenotypic progression of differentiation into macrophages, which may subsequently fuse to form foreign body giant cells (FBGCs). Taking advantage of an in vitro system of cytokine-induced FBGC formation together with the optical slicing capabilities of a confocal microscope, we investigated the cytoskeletal reorganization and adhesive structure development during this dramatic morphological progression. Human monocytes demonstrated diffuse cytoplasmic staining of adhesive structural proteins. Punctate filamentous (F)-actin structures appeared along the ventral cell membrane of macrophages and were identified as the core of podosome adhesive structures by the distinctive ring staining of vinculin, talin, and paxillin around the F-actin. Cytokine-induced FBGCs were characterized by a restriction of podosomes to the extreme periphery of the ventral cell surface. Although macrophages and FBGC contained equivalent amounts of F-actin, significantly more F-actin was located within 1 micron of the ventral plasma membrane in FBGCs compared to macrophages. Taken together, these results provide new information on the dynamic cytoskeletal reorganization and adhesive structure development that occur during phenotypic progression from human monocytes to macrophages to FBGC. Furthermore, they suggest the acquisition of functional specializations on FBGC formation, which may enhance our understanding of chronic inflammatory processes.

Human monocyte/macrophage adhesion, macrophage motility, and IL-4-induced foreign body giant cell formation on silane-modified surfaces in vitro. Student Research Award in the Master's Degree Candidate Category, 24th Annual Meeting of the Society for Biomaterials, San Diego, CA, April 22-26, 1998

A cytokine-based, in vitro model of foreign body giant cell (FBGC) formation was utilized to examine the effect of biomaterial surface chemistry on the adhesion, motility, and fusion of monocytes and macrophages. Human monocytes were cultured for 10 days on 14 different silane-modified glass surfaces, during which time the cells assumed the macrophage phenotype. The adhesion of monocytes and macrophages during the culture period decreased by an average of approximately 50%, with the majority of cell loss observed during days 1-3. Most important, the adhesion of monocytes and macrophages was surface independent except for two surfaces containing terminal methyl groups, which decreased adhesion levels. Interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were added to the medium to induce FBGC formation and enhance macrophage adhesion, respectively. Surprisingly, GM-CSF decreased long-term monocyte/macrophage adhesion. IL-4-induced FBGC density was strongly influenced by the surface carbon content, as determined by X-ray photoelectron spectroscopy (XPS). In contrast, contact angle and surface energy displayed no correlation with FBGC formation. The motility of adherent macrophages, as measured by time-lapse confocal microscopy, was not affected significantly by differences in surface chemistry or the addition of cytokines. The surface dependence of FBGC formation is hypothesized to be the result of varying levels of silane-derived surface carbon.

Treatment of acardiac twinning

BACKGROUND

The twin reversed-arterial-perfusion sequence is a complication of monochorionic twin pregnancies characterized by the hemodynamic dependence of a "recipient" twin from a "pump" twin. The recipient twin exhibits lethal abnormalities including acardia and acephaly. The pump twin has a mortality rate of 50% as a result of high-output heart failure.

CASE

The blood supply to an acardiac-acephalus twin was interrupted at 24 weeks' gestation using endoscopic laser coagulation. The co-twin was delivered at 35 weeks and had an uneventful neonatal course following correction of a persistent patent ductus arteriosus. Review of the literature reveals 22 cases of acardiac twinning treated with invasive procedures, seven of them using endoscopic laser coagulation. Pump twin mortality with fetal surgery was 13.6% in comparison with 50% mortality with expectant management (P < .001).

CONCLUSION

Fetal surgery is the best available treatment for acardiac twinning. Endoscopic laser coagulation at or before 24 weeks and endoscopic or sonographic guided umbilical cord ligation after this gestational age seem to be the best treatments for this condition.

Interleukin-13 induces human monocyte/macrophage fusion and macrophage mannose receptor expression

Inasmuch as we recently demonstrated that IL-4 is a strong inducer of monocyte/macrophage fusion and IL-13 has been observed to mimic many of the biologic effects of IL-4, the ability of IL-13 to promote human macrophage fusion in vitro was tested and compared with IL-4-mediated fusion. IL-13 induced the fusion of monocyte-derived macrophages as potently as IL-4 under identical culture conditions, and resulted in foreign body-type giant cell formation. At optimal concentrations of cytokine added, statistically equal numbers of macrophages participated in IL-13- and IL-4-induced fusion (66.1 +/- 4.6% and 63.9 +/- 4.4%, respectively). However, the effects of IL-13 and IL-4 were not additive or synergistic, and the maximum fusion obtained when both IL-4 and IL-13 were added was 63.8 +/- 3.6%. Only anti-human IL-13 Abs inhibited IL-13-induced foreign body giant cell formation; the fusion-inducing effects of IL-13 continued to be observed in the presence of neutralizing Abs to IL-4 and several other anti-cytokine Abs, including Abs against IFN-gamma, granulocyte-macrophage CSF, IL-3, and TNF-alpha. IL-13 also significantly enhanced the fluorescence intensity detected by anti-human macrophage mannose receptor Abs, indicating that IL-13, like IL-4, up-regulates expression of the receptor that may be an essential participant in macrophage fusion. The results of this study demonstrate that IL-13, like IL-4, is a potent human macrophage fusion factor, and suggest that although IL-13 acts independently of IL-4 to promote foreign body giant cell formation, it may trigger a common mechanism for macrophage fusion.

Interleukin-13 induces human monocyte/macrophage fusion and macrophage mannose receptor expression

Inasmuch as we recently demonstrated that IL-4 is a strong inducer of monocyte/macrophage fusion and IL-13 has been observed to mimic many of the biologic effects of IL-4, the ability of IL-13 to promote human macrophage fusion in vitro was tested and compared with IL-4-mediated fusion. IL-13 induced the fusion of monocyte-derived macrophages as potently as IL-4 under identical culture conditions, and resulted in foreign body-type giant cell formation. At optimal concentrations of cytokine added, statistically equal numbers of macrophages participated in IL-13- and IL-4-induced fusion (66.1 +/- 4.6% and 63.9 +/- 4.4%, respectively). However, the effects of IL-13 and IL-4 were not additive or synergistic, and the maximum fusion obtained when both IL-4 and IL-13 were added was 63.8 +/- 3.6%. Only anti-human IL-13 Abs inhibited IL-13-induced foreign body giant cell formation; the fusion-inducing effects of IL-13 continued to be observed in the presence of neutralizing Abs to IL-4 and several other anti-cytokine Abs, including Abs against IFN-gamma, granulocyte-macrophage CSF, IL-3, and TNF-alpha. IL-13 also significantly enhanced the fluorescence intensity detected by anti-human macrophage mannose receptor Abs, indicating that IL-13, like IL-4, up-regulates expression of the receptor that may be an essential participant in macrophage fusion. The results of this study demonstrate that IL-13, like IL-4, is a potent human macrophage fusion factor, and suggest that although IL-13 acts independently of IL-4 to promote foreign body giant cell formation, it may trigger a common mechanism for macrophage fusion.

Adhesion and cytokine production by monocytes on poly(2-methacryloyloxyethyl phosphorylcholine-co-alkyl methacrylate)-coated polymers

Human monocytes isolated from peripheral venous blood were assayed for their ability to adhere to various polymers. The culture supernatants were also assayed for the cytokines, interleukin-1 beta (IL-beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha). The polymers evaluated for adherence and cytokine production included Pellethane, polyethylene and poly[n-butyl methacrylate (BMA)] coated with poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-co-alkyl methacrylate] copolymers. In some experiments the test polymers were adsorbed with fibrinogen or IgG prior to the addition of monocytes. MPC copolymer-coated materials inhibited monocyte and macrophage adhesion after 1 and 8 days of culture relative to corresponding uncoated polymers and tissue culture polystyrene (TCPS). The degree of inhibition by coated Pellethane compared to uncoated Pellethane was the greatest, while inhibition of adhesion by coated poly(BMA) was the least compared to uncoated poly(BMA). However, adhesion was significantly decreased on both coated and uncoated poly(BMA) by day 8. While IL-1 beta, IL-6, and TNF-alpha release was variably influenced by polymer coating, release was consistently inhibited relative to TCPS on day 1. However, cytokine production was not inhibited compared to corresponding uncoated polymers on day 1. With or without protein preadsorption, IL-1 beta release was not detectable in the supernatants of any polymer on day 8, IL-6 production was diminished on day 8, and TNF-alpha production was sustained on day 8. Overall, MPC copolymer-coated and uncoated poly(BMA) were the least stimulating, while TCPS was the most stimulating.(ABSTRACT TRUNCATED AT 250 WORDS)

Human monocyte/macrophage adhesion and cytokine production on surface-modified poly(tetrafluoroethylene/hexafluoropropylene) polymers with and without protein preadsorption

To study surface property-dependent human monocyte adhesion and cytokine (IL-1 beta, IL-6, TNF-alpha) production, poly(tetrafluoroethylene/hexafluoropropylene) (FEP) polymer was modified to exhibit neutral, anionic, or cationic properties by incorporating amide (CONH2) and/or carboxyl (COOH) or aminoethyl amide [CONH(CH2CH2NH)nCH2CH2NH2] groups on the surface. Monocyte adhesion on surface-modified FEP polymers and cytokines released by monocytes/macrophages (MC/MO) into the culture medium were compared to control tissue culture polystyrene (TCPS) at days 1 and 8. On day 1, the neutral surface FEP polymer with incorporated amide (NH2) groups showed the greatest inhibition of adhesion, 89% (P < .01), and cytokine production (IL-1 beta with 58%, IL-6 with 70%, and TNF-alpha with 39%) compared to control TCPS. In contrast, the highly cationic [CONH(CH2CH2NH)nCH2CH2NH2] surface did not show significant (P > .01) inhibition of monocyte adhesion and cytokine production. When fibrinogen or IgG was preadsorbed to the surface, the inhibitory effects of the neutral surface FEP polymer on monocyte adhesion and cytokine production were not altered. In addition, other surface-modified FEP polymers showed similar inhibition of monocyte adhesion and cytokine production compared to TCPS. Specifically, as the incorporation of carboxyl (COOH) group content increased on FEP polymer surfaces, monocyte adhesion and cytokine production were also increased on day 1 with IgG preadsorption. On day 8, all surface-modified FEP polymers showed significant (P < .01) inhibition of monocyte adhesion when fibrinogen or IgG was preadsorbed. However, without protein (fibrinogen or IgG) preadsorption, monocyte adhesion was not significantly inhibited compared to control TCPS. In addition, cytokine production detected by ELISAs on day 8 showed no detectable levels of IL-1 beta and significantly decreased levels of IL-6 compared to day 1 for all tested polymers, with or without protein preadsorption. Interestingly, the level of TNF-alpha production on day 8 remained high although not as high as on day 1. Based on these results, we suggest that FEP polymers with neutral hydrophilic surface properties may adhere and activate the least number of monocytes, which are important mediators of biocompatibility.

Cytokine and growth factor production by monocytes/macrophages on protein preadsorbed polymers

These studies evaluate the effect of biomedical polymers: Biomer, polydimethyl-siloxane (PDMS), polyethylene, expanded polytetrafluoroethylene (ePTFE), Dacron, and the control polystyrene with or without adsorbed proteins IgG, fibrinogen, and fibronectin on the ability of activated human monocytes/macrophages to produce Interleukin 1 Beta (IL-1-B), Interleukin 6 (IL-6), and Tumor Necrosis Factor Alpha (TNF-A). Monocytes/macrophages incubated on biomedical polymers with or without protein preadsorption produce variable levels of IL-1-B, IL-6, and TNF-A dependent on the polymer and adsorbed protein. IL-6 was produced in the greatest quantity and was the most influenced by protein adsorption. ePTFE and PDMS polymers were least stimulating while polystyrene was the most stimulating of monocyte activity. Adsorbed IgG consistently altered the ability of the polymers to activate monocytes/macrophages to produce cytokines. These studies provide important insight into conditions which modulate monocyte/macrophage activity in response to protein preadsorbed biomedical polymers.

Protein adsorption of biomedical polymers influences activated monocytes to produce fibroblast stimulating factors

The studies presented in this manuscript were based upon the hypothesis that monocytes/macrophages selectively produce cytokines and growth factors due to their interactions with polymers and proteins which are adsorbed to their surfaces. These factors in turn selectively influence the ability of fibroblasts to proliferate. The factors which influence fibroblast proliferation were released from monocytes incubated with polymers: Biomer, polydimethylsiloxane (PDMS), polyethylene (PE), expanded polytetrafluoroethylene (ePTFE), Dacron, and control polystyrene with and without preadsorption with physiological concentrations of IgG, fibrinogen, fibronectin, hemoglobin, or albumin. No simple correlation was found between adsorbed protein, biomedical polymer, and the ability of monocytes to produce growth factors and cytokines which influence fibroblast proliferation. This is evidence for selective protein-polymer interactions which in turn selectively activate monocytes to produce variable cell cycle competence and progression factors controlling fibroblast growth.

Fibroblast stimulation by monocytes cultured on protein adsorbed biomedical polymers. I. Biomer and polydimethylsiloxane

The studies presented in this paper evaluate the modulatory role of protein pre-adsorbed polydimethylsiloxane (PDMS) and Biomer on the secretion of fibroblast stimulating growth factors from human monocytes/macrophages. The results of these studies show that Biomer and PDMS selectively activate human monocytes to produce fibroblast "progression-like" and to a lesser extent "competence-like" stimulating growth factors. Polydimethylsiloxane stimulated the monocytes/macrophages to produce more "progression-like" fibro-blast stimulating growth factors than Biomer. The induction of "competence-like" fibroblast stimulating activity from the monocytes was enhanced by preadsorption of PDMS with human derived fibrinogen, fibronectin, IgG, hemoglobin, or albumin. This phenomenon was not observed with protein pre-adsorbed Biomer. These studies support the hypothesis that protein pre-adsorbed polymers will selectively modulate monocyte/macrophage activation and induction of growth factors which have the potential to participate in tissue-implant interactions in vivo.

Plasma protein adsorbed biomedical polymers: activation of human monocytes and induction of interleukin 1

These studies involved the evaluation of human monocyte/macrophage activation by biomedical polymers coated with human blood proteins. The biomedical polymers were polyethylene, polydimethylsiloxane, woven Dacron fabric, expanded polytetrafluoroethylene, Biomer, and tissue culture treated polystyrene as the control. They were adsorbed with human blood proteins: albumin, fibrinogen, fibronectin, hemoglobin, and gamma globulin. The protein adsorbed polymers were evaluated for their potential to activate the monocyte/macrophage cellular population in vitro as assessed by the induction of the monocyte/macrophage inflammatory mediator, Interleukin 1 (IL1). Suppression of IL1 was observed when protein adsorbed polymers were compared to the appropriate protein adsorbed control. Protein adsorbed polymers, when compared to polymers without protein adsorption, stimulated IL1 production. The data presented in this manuscript show the level of induction and secretion of IL1 was dependent on the biomedical polymer and the protein adsorbed, as well as the requirement of lipopolysaccharide. These results show differential interactions occur between the proteins, monocytes/macrophages, and biomedical polymers which alter activation and induction of IL1.

Collateralization and GAD immunoreactivity of descending pallidal efferents

The first phase of this study involves injecting a different fluorescent retrograde axonal tracer into the subthalamic nucleus, the substantia nigra, and the mesopontine tegmentum. Multiple labeled cells are found within the caudal third of the globus pallidus. The entopeduncular nucleus and adjacent basal forebrain structures such as the substantia innominata, lateral hypothalamus, bed nucleus of the stria terminalis, and central nucleus of the amygdala all exhibit some dye containing cell, although multiple labeled cells are rare. The second phase of this study involves injecting a different fluorescent retrograde tracer into either the substantia nigra, or the mesopontine tegmentum, and subsequent processing of the tissue for glutamic acid decarboxylase (GAD) immunocytochemistry. Many dye and antibody double-labeled cells could be found within the entopeduncular nucleus and the caudal third of the globus pallidus. This is in contrast to the surrounding basal forebrain regions with brainstem efferents which were rarely GAD-positive. This study indicates that the collateral pattern and immunocytochemistry of globus pallidus neurons with descending efferents are distinct from other basal forebrain neurons having similar efferents. These results also extend previous findings and suggest that the neuron of the pallidal complex are heterogeneous with respect to their patterns of projections. In particular, the present findings question previous assumptions concerning the homology of pallidal segments between primate and rodent species.