Predicting attractor characteristics using Lyapunov exponents in a laser with injected signal.

Coexisting attractors are studied in a single-mode coherent model of a laser with an injected signal. We report that every attractor has a unique Lyapunov exponent (LE) pattern that is choreographed by the subtle variations in the attractor's dynamics and circumscribed by a common Lyapunov spectral pattern that begins and ends with two-zero LEs. Lyapunov spectra form symmetric-like and asymmetric bubbles; the former foreshadows an attractor's proximity to the cusp of an eminent change in dynamics and the latter indicates the presence of a bifurcation. We show that the peak values of the asymmetric bubbles are always associated with two-zero LEs; in fact, they are allied inseparably in forecasting period-doubling episodes. The two-zero LEs' predictor of torus dynamics is refined to include the convergence of three LEs to a triplet of zeros as a precursor to the two-zero spectra. We report that the long-standing two-zero LEs' signature is a necessary but not sufficient condition for predicting attractors and their dynamic conditions. The evolution of the attractor volume as a function of the injected signal is compared to the spectral formation of the attractor; we report slope changes and points of inflections in the volume trajectory where spectral changes indicate dynamic changes. Attractor viability is tested preliminarily by including random low-level noise in the frequency of the injected signal.

Homogeneity of mesothelial cells with lymphatic endothelium: expression of lymphatic endothelial markers by mesothelial cells.

BACKGROUND: Mesothelial cell monolayers cover the serous cavities and internal organs, and provide a protective low-friction interface between apposed organs and tissues. The mesothelium also regulates inflammation, fluid and cell exchange, and tissue repair in these compartments and possibly tumor metastasis. In the present study, a stable pleural mesothelial cell line (MIM) was isolated and characterized, and the expression of several lymphatic specific markers by these cells examined. METHODS AND RESULTS: MIM were isolated from mice stably expressing a temperature-sensitive SV40 large T antigen ('Immortomouse', strain: H-2K(b)-tsA58). These cells were compared with lymphatic endothelial cells (LEC) derived from the mesenteric adventitia of the Immortomouse. MIM and LEC expression of lymphatic-specific markers (Flt-4, LYVE-1, and Prox-1) was examined, and the tight junction protein (ZO-1) was studied by immunofluorescence and immunoblotting in these cells. RESULTS: LYVE-1, Prox-1, and Flt-4 were detected in both MIM and LEC, with Prox-1 and LYVE-1 more strongly expressed on LEC than MIM. Conversely, Flt-4 was more densely expressed on MIM than on LEC. Spatially, ZO-1 was prominent at MIM junctions, but was less well organized in LEC. CONCLUSION: MIM and LEC share several characteristic markers usually associated with lymphatic endothelium. MIM might be useful for studying the biology and pathology of mesothelial cells in vitro and help in the development of therapies for mesothelial-related diseases, such as mesothelioma and pleural effusion.

MAdCAM-1 expression and regulation in murine colonic endothelial cells in vitro.

BACKGROUND: Although the mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is associated with the etiology of inflammatory bowel diseases, few studies have directly examined MAdCAM-1 using microvascular endothelium derived from the colon. This study measured the expression of MAdCAM-1 in a novel colon endothelial line MJC-1, as well as MAdCAM-1 regulation and function in vitro. METHODS: We cloned microvascular endothelial cells from primary colon cultures using ImmortoMice mice (whose cells express a temperature-sensitive SV40 large T antigen, H-2Kb-tsA58 mice). Expression of MAdCAM-1 after stimulation with cytokines [tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, or interferon (IFN)-gamma] was determined by Western blotting. Signal paths regulating MAdCAM-1 expression were examined using pharmacological blockers before cytokines. We also examined lymphocyte adhesion using lymphocytes that constitutively express alpha4beta7 integrin. RESULTS: TNF-alpha induced MAdCAM-1 in a dose-dependent manner by 24 hours. MAdCAM-1 induction was protein kinase C, tyrosine kinase, p38 mitogen activated protein kinase, and nuclear-factor kappa-B/poly adenosine diphosphate ribose polymerase dependent. Lymphocyte adhesion was increased 2.6-fold after TNF-alpha stimulation and was inhibited by anti-MAdCAM-1 antibody before treatment (P < 0.05 control versus TNF-alpha). CONCLUSIONS: In vitro, MAdCAM-1 can be induced on colon endothelial cells by TNF-alpha stimulation and may represent a useful model to study microvascular injury in the large intestine.

N-methyl-D-aspartate receptor activation in human cerebral endothelium promotes intracellular oxidant stress.

Cerebral endothelial cells in the rat, pig, and, most recently, human have been shown to express several types of receptors specific for glutamate. High levels of glutamate disrupt the cerebral endothelial barrier via activation of N-methyl-d-aspartate (NMDA) receptors. We have previously suggested that this glutamate-induced barrier dysfunction was oxidant dependent. Here, we provide evidence that human cerebral endothelial cells respond to glutamate by generating an intracellular oxidant stress via NMDA receptor activation. Cerebral endothelial cells loaded with the oxidant-sensitive probe dihydrorhodamine were used to measure intracellular reactive oxygen species (ROS) formation in response to glutamate receptor agonists, antagonists, and second message blockers. Glutamate (1 mM) significantly increased ROS formation compared with sham controls (30 min). This ROS response was significantly reduced by 1) MK-801, a noncompetitive NMDA receptor antagonist; 2) 8-(N,N-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate, an intracellular Ca(2+) antagonist; 3) LaCl(3), an extracellular Ca(2+) channel blocker; 4) diphenyleiodonium, a heme-ferryl-containing protein inhibitor; 5) itraconazole, a cytochrome P-450 3A4 inhibitor; and 6) cyclosporine A, which prevents mitochondrial membrane pore transition required for mitochondrial-dependent ROS generation. Our results suggest that the cerebral endothelial barrier dysfunction seen in response to glutamate is Ca(2+) dependent and may require several intracellular signaling events mediated by oxidants derived from reduced nicotinamide adenine dinucleotide oxidase, cytochrome P-450, and the mitochondria.

Increased disease activity in eNOS-deficient mice in experimental colitis.

Oral dextran sodium sulfate (DSS, 3%) produces experimental colitis with many features of human inflammatory bowel disease (IBD), (leukocyte extravasation, cachexia, and histopathology). Previous studies suggest that the inducible nitric oxide synthase (iNOS) in blood cells or in the endothelium contribute to this injury. However, until now no study has been performed to directly evaluate the role of endothelial nitric oxide synthase (eNOS) in IBD. We compared disease activity in wild-type (eNOS+/+) and eNOS-deficient (eNOS-/-) mice in the DSS model of colitis. Administration of DSS induced weight loss, stool blood, and overt histopathology in both mouse strains. Disease activity was dramatically increased in eNOS-/- mice compared to wild types. Histologically, eNOS-deficient mice had greater leukocyte infiltration, gut injury, and expressed higher levels of the mucosal addressin, MAdCAM-1. These results demonstrate that eNOS plays an important role in limiting injury to the intestine during experimental colitis and altered eNOS content and/or activity may contribute to human IBD.

Glutamate causes a loss in human cerebral endothelial barrier integrity through activation of NMDA receptor.

l-Glutamate is a major excitatory neurotransmitter that binds ionotropic and metabotropic glutamate receptors. Cerebral endothelial cells from many species have been shown to express several forms of glutamate receptors; however, human cerebral endothelial cells have not been shown to express either the N-methyl-D-aspartate (NMDA) receptor message or protein. This study provides evidence that human cerebral endothelial cells express the message and protein for NMDA receptors. Human cerebral endothelial cell monolayer electrical resistance changes in response to glutamate receptor agonists, antagonists, and second message blockers were tested. RT-PCR and Western blot analysis were used to demonstrate the presence of the NMDA receptor. Glutamate and NMDA (1 mM) caused a significant decrease in electrical resistance compared with sham control at 2 h postexposure; this response could be blocked significantly by MK-801 (an NMDA antagonist), 8-(N,N-diethylamino)-n-octyl-3,4,5-trimethyoxybenzoate (an intracellular Ca2+ antagonist), and N-acetyl-L-cystein (an antioxidant). Trans(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid, a metabotropic receptor agonist (1 mM), did not significantly decrease electrical resistance. Our results are consistent with a model where glutamate, at excitotoxic levels, may lead to a breakdown in the blood brain barrier via activation of NMDA receptors.

Expression of junctional proteins in human platelets.

Platelets play a major role in thrombosis and hemostasis by binding the sub-endothelial matrix at sites of injury, but also participate in vascular pathologies such as atherosclerosis. Recently, junctional proteins like PECAM-I and JAM-family members have been recovered from platelets, therefore we examined what other junctional molecules may be present in platelets. We observed immunoreactivity for APC (147 kD), beta-catenin (92 kD), E-cadherin (120 and 84 kD) and occludin (70-85 kD) by western blotting. Additionally, beta-catenin, pan-reactive cadherins, E-cadherin and occludin were seen to partition with the triton insoluble cytoskeleton in platelets. These proteins were also found in a megakaryocyte (platelet precursor) line, MEG-01. Our data suggest that conventional junctional molecules are expressed in platelets and could possibly participate in aggregation, clot formation and wound healing.

TNF-alpha -induced endothelial cell adhesion molecule expression is cytochrome P-450 monooxygenase dependent.

It is strongly suspected that cytokine-induced gene expression in inflammation is oxidant mediated; however, the intracellular sources of signaling oxidants remain controversial. In inflammatory bowel disease (IBD) proinflammatory cytokines, such as TNF-alpha, trigger gene expression of endothelial adhesion molecules including mucosal addressin cell adhesion molecule-1 (MAdCAM-1). MAdCAM-1 plays an essential role in gut inflammation by governing the infiltration of leukocytes into the intestine. Several groups suggest that endothelial-derived reduced NADP (NADPH) oxidase produces signaling oxidants that control the expression of adhesion molecules (E-selectin, ICAM-1, VCAM-1). In addition to NADPH oxidase, cytochrome P-450 (CYP450) monooxygenases have also been shown to trigger cytokine responses. We found that in high endothelial venular cells (SVEC4-10), multiple inhibitors of CYP450 monooxygenases (SKF-525a, ketoconazole, troleandomycin, itraconazole) attenuated TNF-alpha induction of MAdCAM-1, whereas NADPH oxidase inhibition (PR-39) did not. Conversely, E-selectin, ICAM-1, and VCAM-1 induction requires both NADPH oxidase and CYP450-derived oxidants. We show here that MAdCAM-1 induction may depend exclusively on CYP450-derived oxidants, suggesting that CYP450 blockers might represent a possible novel therapeutic treatment for human IBD.

Carcinoid tumor development in an intramedullary spinal cord mature teratoma.

The case of a 43-year-old woman with a several month history of severe back pain is reported. CT and MR imaging revealed an intramedullary cystic tumor, which was considered a dermoid cyst or teratoma. During surgery, the tumor was found within the base of the filum terminale and completely resected. Microscopic studies revealed a mature teratoma with an intramural carcinoid nodule. Thirteen-month follow-up after surgical resection showed no evidence of tumor recurrence or neoplasms elsewhere.

Roles of leukocyte and immune cell junctional proteins.

The restricted expression of E-cadherin on dendritic cells and intraepithelial lymphocytes has been described as a structural/adhesive system that helps to retain and integrate these cells within mucosal and dermal tissues. The activation of these cells downregulates expression of cadherins, and contributes to cell redistribution and tissue homing. It has recently been reported that lymphocytes and other leukocytes express cadherins, as well as occludin, a tight junctional component, in response to several types of stimuli. This suggests that mobilization of adherens and tight junction proteins in leukocytes may facilitate interactions of leukocytes with epithelial, endothelial, and interstitial cells that express these proteins and support homophilic adhesion. The conditions and patterns of synthesis of these adhesion molecules, in antigen-presenting cells and leukocytes, indicate that the expression of junction proteins may play roles in normal and pathological leukocyte traffic.

Reciprocal regulation of endothelial substrate adhesion and barrier function.

OBJECTIVE: To examine how cell-substrate adhesion is regulated during barrier changes produced by exposure to inflammatory mediators. METHODS: Lung microvascular endothelial monolayers were treated with test agents +/- blockers, and barrier was measured by transendothelial resistance; cell-substrate adhesion was assessed by surface area conservation after trypsin treatment of monolayers. Protein phosphorylation and distribution were assayed by immunoblotting and fluorescent microscopy, respectively. RESULTS: H2O2, histamine, bradykinin, and thrombin, decreased endothelial barrier function, and enhanced adhesion to the substratum. H2O2 enhanced cell adhesion to the substrate in a concentration (0-1 mM)- and time (0-60 minutes)-dependent fashion. This effect of H2O2 reversed within 120 minutes of removal of H2O2 and was blocked by the mean arterial pressure (MAP) kinase inhibitor, PD98059 and by chelating cytoplasmic Ca2+ but not PKC or PKG inhibition. H2O2 also stimulated tyrosine phosphorylation of several proteins and increased the association of the focal adhesive proteins paxillin, talin, and vinculin with the cytoskeleton and may promote localization of these proteins to junctions. CONCLUSIONS: Our data indicate that inflammatory mediators reduce cell-cell contact, contributing to reduced solute barrier and simultaneously enhanced substrate binding, which may be reciprocal events in barrier regulation in vitro and in vivo.

Serologic survey for hantavirus infection in domestic animals and coyotes from New Mexico and northeastern Arizona.

OBJECTIVE: To determine whether animals had serologic evidence of infection with Sin Nombre virus (SNV). DESIGN: Prospective serosurvey. SAMPLE POPULATION: Serum samples were obtained from 145 cats, 85 dogs, 120 horses, and 24 cattle between April 1993 and August 1994 and 54 coyotes between December 1994 and February 1995. PROCEDURE: Serum samples were analyzed by western immunoblot assays for reaction with SNV nucleocapsid antigen. Samples with reactivity to SNV nucleocapsid proteins were used to probe multiple-antigen blots containing recombinant fusion proteins derived from prototypic hantaviruses. Lung tissue or blood clots were used in nested reverse-transcriptase polymerase chain reaction assays for a 320-nucleotide portion of the SNV G1 gene. RESULTS: Sera from 4 of 145 (2.8%) cats and 4 of 85 (3.5%) dogs had trace reactivity to full-length SNV-encoded nucleocapsid proteins. All samples from horses, cattle, and coyotes were nonreactive. Sera from cats and dogs that had trace IgG-antibody reactivity to nucleocapsid proteins were then tested for IgG-antibody reactivity to nucleocapsid proteins of prototypic hantaviruses. One cat had multiple cross-reactivities with these hantaviruses, consistent with exposure to a hantavirus; however, epitope mapping studies did not support this conclusion. Reverse-transcriptase polymerase chain reaction studies of blood clots or lung tissue from 2 animals that had weak reactivity to SNV failed to amplify any hantavirus sequence. CLINICAL IMPLICATIONS: Domestic animals, particularly dogs and cats, as well as coyotes do not appear to have a major role in the maintenance and transmission of SNV.

Tumoral presentation of amyloidosis (amyloidomas) in soft tissues. A report of 14 cases.

Amyloidosis in its diverse types (immunocytic dyscrasia-associated, reactive, or heredofamilial) most often presents in a systemic form. Localized amyloidosis is uncommon in general and is exceedingly rare in the soft tissues. The authors discuss the cases of 14 patients in whom amyloidosis manifested as a localized mass ("amyloidoma") in the soft tissues (mostly mediastinal and retroperitoneal), leading to a clinical diagnosis of neoplasm in most cases. On the basis of the associated morphologically atypical and phenotypically monoclonal cell population, the resistance to potassium permanganate pretreatment, and the lack of reactivity with anti-AA antisera, 10 cases could be classified as immunocytic dyscrasia-associated AL-amyloidosis. However, four cases had histopathologic and histo- and immunohistochemical characteristics of reactive ("secondary") AA-amyloidosis. This proportion (28.5%) was higher than that suggested by the sporadic AA-amyloidomas reported in the literature. The pathologic distinction between these two categories is important because patients with AA-amyloidomas of the soft tissues appear to have a better prognosis.

Parental involvement in sexual abuse prevention education.

Parental knowledge of child sexual abuse and interest in educating themselves and their children for primary prevention was studied. Fifty-one mothers and 50 fathers of preschool and day-care center children were interviewed. Parents wanted to be the primary educators of their child, but demonstrated a lack of knowledge about important sexual abuse issues and planned to discuss only the least threatening topics. Mothers and fathers obtained most of their information about sexual abuse from the media. However, parents were open to numerous methods and referral sources for prevention education. One dependent variable, sex of parent, showed significant differences on sources of sexual abuse information; preferred educators for their children; number and types of topics acceptable for children to learn about at preschool ages or other times; the number of topics parents planned to discuss; sources parents would respond to most for a parent program; and factors in parent's decision to attend parent programs. There were no significant differences based upon the sex of the child and no significant interaction effects between sex of parent and sex of child. Further research on parent motivation for their own education and the education of their children is indicated.

Human Curvularia infections. Report of five cases and review of the literature.

Curvularia lunata is a saprobic dematiaceous mould that resides primarily in soil (Ellis, 1966). Reports of human disease caused by this organism are rare but include: endocarditis, brain abscess, skin infections, onychomycosis, keratitis, pneumonia, disseminated disease, mycetoma, allergic bronchopulmonary disease, and one case of sinusitis. Since 1983, we have encountered five cases of paranasal sinusitis due to C. lunata. None of the patients suffered from known immunologic disorders or underlying debilitating diseases. These five cases are presented and the literature of human phaeohyphomycosis caused by Curvularia spp. is reviewed.