Development of an adverse outcome pathway network for nephrotoxicity.

Adverse outcome pathways (AOPs) were introduced in modern toxicology to provide evidence-based representations of the events and processes involved in the progression of toxicological effects across varying levels of the biological organisation to better facilitate the safety assessment of chemicals. AOPs offer an opportunity to address knowledge gaps and help to identify novel therapeutic targets. They also aid in the selection and development of existing and new in vitro and in silico test methods for hazard identification and risk assessment of chemical compounds. However, many toxicological processes are too intricate to be captured in a single, linear AOP. As a result, AOP networks have been developed to aid in the comprehension and placement of associated events underlying the emergence of related forms of toxicity-where complex exposure scenarios and interactions may influence the ultimate adverse outcome. This study utilised established criteria to develop an AOP network that connects thirteen individual AOPs associated with nephrotoxicity (as sourced from the AOP-Wiki) to identify several key events (KEs) linked to various adverse outcomes, including kidney failure and chronic kidney disease. Analysis of the modelled AOP network and its topological features determined mitochondrial dysfunction, oxidative stress, and tubular necrosis to be the most connected and central KEs. These KEs can provide a logical foundation for guiding the selection and creation of in vitro assays and in silico tools to substitute for animal-based in vivo experiments in the prediction and assessment of chemical-induced nephrotoxicity in human health.

Association of a gene expression profile from whole blood with disease activity in systemic lupus erythaematosus.

OBJECTIVE: To determine whether peripheral blood gene expression of patients with systemic lupus erythaematosus (SLE) correlates with disease activity measured using the SLE Disease Activity Index 2000 (SLEDAI-2K). METHODS: RNA was isolated from peripheral blood of 269 patients with SLE and profiled on a custom microarray. Hierarchical clustering and a heat map were used to categorise samples into major clusters based on gene expression pattern. Correlates, including demographic and disease-related characteristics such as SLEDAI-2K score, of the major sample clusters were compared using multivariate regression models. RESULTS: A set of 31 interferon (IFN)-regulated genes were seen to be driving the separations of samples into two clusters, one characterised by a relatively high IFN-regulated gene signature (n = 150) and the other by a relatively low IFN-regulated gene signature (n = 119). Disease activity measured using the SLEDAI-2K was significantly correlated with the high IFN gene signature. In multivariate regression analysis the immunological component of the SLEDAI-2K was a significant correlate of the high IFN gene signature as was presence of antibodies to U1RNP. There were no discernable correlates of the 156 non-IFN regulated genes profiled on the custom array. CONCLUSION: Peripheral blood gene expression profiling (GEP) in SLE allows patients to be categorised into two groups based on a high or low IFN gene signature. Disease activity measured using the SLEDAI-2K is correlated with the high IFN gene signature, indicating that GEP may be a useful biomarker of disease activity in SLE.

Leukocyte gene expression signatures in antineutrophil cytoplasmic autoantibody and lupus glomerulonephritis.

Leukocytes play a major role in the development and progression of autoimmune diseases. We measured gene expression differences in leukocytes from patients that were antineutrophil cytoplasmic autoantibody (ANCA) positive, patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA), and healthy donors to explore potential pathways for clinical intervention. Leukocyte gene expression profiles were determined on Affymetrix U133A/B chips in 88 autoimmune patients, 28 healthy donors, and healthy donor leukocyte cell subtypes that were activated in vitro. Comparison of gene expression in leukocytes identified differentially expressed signature genes that distinguish each donor source. The microarray expression levels for many signature genes correlated with the clinical activity of small vessel vasculitis in the ANCA patients; a result confirmed by quantitative real time-polymerase chain reaction for 16 relevant genes. Comparison with in vitro-activated leukocyte subtypes from healthy donors revealed that the ANCA signature genes were expressed by neutrophils while the SLE signature genes were expressed in activated monocytes and T cells. We have found that leukocyte gene expression data can differentiate patients with RA, SLE, and ANCA-related small vessel vasculitis. Monitoring changes in the expression of specific genes may be a tool to help quantify disease activity during treatment.

Characterization of a monoclonal antibody reacting with antigen-4 domain of gp900 in Cryptosporidium parvum invasive stages.

Cryptosporidium parvum (Protozoa, Apicomplexa) infects the apical surface of intestinal epithelial cells, where it grows and divides within a membrane-bound parasitophorous vacuole. gp900, an abundant glycoprotein of C. parvum merozoites and sporozoites, is localized in micronemes and at the surface of invasive stages and participates in the invasion process. Here, we describe a new monoclonal antibody (mAb) against gp900. As shown by immunofluorescence of excysted parasites and immunoelectron microscopy of infected tissues, the mAb reacted with micronemes present in the apical pole of invasive stages. In immunoprecipitation experiments, the mAb was shown to react with a high molecular weight antigen co-migrating with gp900. Finally, three reactive clones were selected upon screening of a C. parvum genomic expression library with the mAb; and sequencing of the insert from one of them showed a 596 bp sequence identical to the DNA region encoding a domain of gp900 identified as antigen 4.

The influence of contour line size and location on the reproducibility of topographic measurement with the Heidelberg Retina Tomograph.

BACKGROUND: The recommended contour line (CL) location with the Heidelberg Retina Tomograph (HRT) is on the inner edge of Elschnig's scleral ring. This study investigated HRT parameter reproducibility when: (i) the CL size is altered relative to Elschnig's ring; (ii) the CL is either redrawn or imported between images. METHODS: Using the HRT, seven 10 degrees images were acquired for 10 normal volunteers and 10 primary open angle glaucoma (POAG) subjects. A CL was drawn on one image for each subject using Elschnig's scleral ring for reference and imported into subsequent images. The CL diameter was then (a) increased by 50 microns; (b) increased by 100 microns; and (c) decreased by 50 microns. To investigate the effect of the method of contour line transfer between images a CL was: (1) defined for one image and imported to 6 subsequent images; (2) drawn separately for each image. RESULTS: Parameter variability improved as the size of the CL increased for the normal group relative to Elschnig's ring but was unchanged in the POAG group. The export/import function (method 1) resulted in better parameter reproducibility than the redrawing method for both groups. CONCLUSIONS: The exporting and importing function resulted in better parameter variability for both subject groups and should be used for transferring CLs across images for the same subject. Increasing the overall CL size relative to Elschnig's scleral ring improved the reproducibility of the measured parameters in the normal group. No significant difference in parameter variability was observed for the POAG group. This suggests that the reproducibility of HRT images are affected more by the variation in topography between images than change in CL definition.

Effects of pre- and post-thaw thermal insults on viability characteristics of cryopreserved bovine semen.

The magnitude of damage to the viability of cryopreserved bovine spermatozoa by pre- and post-thaw thermal insults was compared. Semen collected by artificial vagina from 5 Holstein bulls was diluted in egg yolk-citrate-7% glycerol extender (EYCG) and cryopreserved in 0.5 mL French straws at a sperm concentration of 40 to 60 x 10(6) cells/mL. In Experiment 1, straws were subjected to 22, 5 or -18 degrees C static air temperature for a duration of 1, 2, 3, 4 or 5 min before or after thawing in a 37 degrees C water bath for 1 min. Control straws were thawed in a 37 degrees C water bath for 1 min without further thermal insult. In Experiment 2, straws were thawed for 1 min in a 37 (control), 20 or 5 degrees C water bath, or were loaded into an insemination gun and plunged into a 37 degrees C water bath for 3 min. In both experiments, straws were returned to a 37 degrees C water bath for incubation prior to viability analysis. Viability evaluations, conducted in triplicate, included the percentage of motile spermatozoa at 1 min and at 3 h post thermal insult and the percentage of intact acrosomal membranes at 3 h post thermal insult. In both experiments, acrosomal integrity was more sensitive than motility to thermal insult. In Experiment 1, a significant interaction was observed between timing of thermal insult (pre- or post-thaw), static air temperature and duration of straw exposure. At 22 and 5 degrees C, thermal insults applied before thawing significantly (P<0.05) reduced acrosomal integrity at > or = 2 and > or = 4 min of exposure, respectively. However, post-thaw exposure to 22 and 5 degrees C for up to 5 min had no effect on any of the sperm viability parameters evaluated. In contrast, at -18 degrees C static air temperature, post-thaw exposure for > or = 3 min decreased acrosomal integrity (P<0.05), while 5 min of pre-thaw exposure was required for alteration of acrosomal integrity. In Experiment 2, each alternative thawing method resulted in significantly (P<0.05) lower incubated acrosomal integrity relative to the controls. These findings suggest that bovine spermatozoa cryopreserved in EYCG extender are more sensitive to pre-thaw than post-thaw thermal insults and that acrosomal integrity following 3-h incubation at 37 degrees C is superior to motility evaluations for detection of damage to sperm viability due to thermal insult.

A novel multi-domain mucin-like glycoprotein of Cryptosporidium parvum mediates invasion.

Cryptosporidium parvum is a protozoan parasite which produces self-limited disease in immunocompetent hosts and devastating, persistent diarrhea in immunocompromised individuals. There is no effective treatment for cryptosporidiosis and little is known about the basic biology of the organism. Cloning and sequence analysis of the gene encoding GP900, a previously identified > 900 kDa glycoprotein, predicts a mucin-like glycoprotein composed of distal cysteine-rich domains separated by polythreonine domains and a large membrane proximal N-glycosylated core region. A trinucleotide repeat composed predominantly of the triplet ACA encodes the threonine domains. GP900 is stored in micronemes prior to appearance on the surface of invasive forms. The concentration of native GP900 which inhibits 50% (IC50) of invasion in vitro is low picomolar; the IC50 for a recombinant cysteine rich-domain is low nanomolar. These observations indicate that GP900 is a parasite ligand for a host receptor involved in attachment/invasion and suggest that immunotherapy or chemotherapy directed against GP900 may be feasible.

Characterization of turkey spermiophages with regard to traits common to macrophages.

Turkey peritoneal exudate cells (PEC) and spermiophages (SMO) were assayed for characteristics of macrophages. The PEC elicited by i.p. injection of 3% Sephadex and SMO isolated from semen using Percoll were cultured in Dulbecco's Modified Eagle Medium supplemented with 20% bovine calf serum (DMEM-20) for 24 h at 41 C in 5% CO2 to provide adherent cells for assays. Most PEC and SMO showed esterase activity (99.3 +/- 0.6 and 98.8 +/- 0.9%, respectively), and exhibited nonspecific phagocytosis of carbon (89.5 +/- 3.6 and 95.3 +/- 0.6%, respectively), zymosan (26.5 +/- 7.6 and 24.3 +/- 2.5%, respectively), bacteria (11.3 +/- 0.8 and 9.3 +/- 0.3%, respectively), and opsonized and nonopsonized SRBC. Maximum uptake of SRBC was seen by 2 h for PEC but not until 4 h for SMO. At time of maximum uptake, SRBC were noted in 35 to 40% of PEC but only in 15 to 20% of SMO. Turkey IgG-FITC bound to both PEC and SMO, but goat anti-turkey IgG-FITC bound only to SMO. Increased nitrite was found in turkey semen after 24 h storage, with highest levels in samples in which SMO were added. Nitrite production was demonstrated using adhered PEC, but SMO could not be tested due to low cell numbers. This research clearly identifies SMO as having macrophage-like activities. Accordingly, these cells may possess the ability to process and present antigen via histocompatibility receptors. Such activity could lead to immune directed responses, including antibody production or activation of cytotoxic T-lymphocytes.

Effects of varying aeration treatment on fertilizing capacity of semen diluted with perfluorochemical emulsion and stored for twenty-four hours.

The effects of perfluorochemical (PFC) oxygen carriers in turkey semen diluents on fertility and hatchability was measured for a 10-wk period. Semen was diluted (1:1) with Beltsville Poultry Semen Extender (BPSE) or BPSE:FC-75, an emulsified mixture of BPSE and perfluorobutyltetrahydrofuran (technical grade) (FC-75) and stored for 24 h at 5 C with agitation (150 rpm) and aeration with either air, nitrogen (100%), or oxygen (100%). Sperm concentration and percentage of dead sperm were determined prior to and after storage. Sperm concentration (8.35 to 9.21 x 10(9) per milliliter) was not significantly affected by the type of diluent or aeration gas, and only stored semen diluted with BPSE: FC-75 and aerated with nitrogen had increased percentage of dead sperm. Diluent type did not affect the percentage of fertilized eggs; however, fertility and hatchability for both diluent treatments with nitrogen aeration was significantly lower (P < or = 0.05) than for the semen treatments with air or oxygen aeration. Hatchability for semen diluted with BPSE:FC-75 and aerated with oxygen (63.7%) was significantly higher (P < or = 0.05) than that for BPSE-diluted semen aerated with oxygen (43.2%). Although use of oxygen carrying fluorocarbon emulsified with BPSE did not further improve fertility when the semen was stored for 24 h while oxygenated and mechanically agitated, a beneficial effect was noted for hatchability. The fact that nitrogen severely depressed fertility confirms that the beneficial effects of agitation are due to oxygenation of the spermatozoa. Therefore, further studies of oxygen carriers in semen are warranted.

TNF-alpha and IL-1beta cross-desensitization of astrocytes and astrocytoma cell lines.

Exposure of human astrocytes and astrocytoma cell lines to TNF-alpha, IL-1beta and gammaIFN induce expression of a specific member of the intercrine/chemokine family of cytokines, RANTES. Pre-incubation with non-stimulatory concentrations of TNF-alpha inhibit IL-1beta-stimulated RANTES expression and similarly, non-stimulatory concentrations of IL-1beta inhibits TNF-alpha induced RANTES expression. The lowered responsiveness of these cells is stably maintained for at least 24 h. The inhibitory effect of TNF-alpha on IL-1beta-induced responses was mediated by TNF receptor-1 since low concentrations of a specific anti-TNF receptor-1 antiserum mimicked the inhibitory effect. These results indicate that TNF and IL-1 receptors mediate pro- and antiinflammatory responses in a concentration dependent manner, suggesting that at low receptor occupancy, TNF and IL-1 receptors may share a common signaling pathway and behave as endogenous antiinflammatory cytokines.

Polyclonal antibody directed against human RANTES ameliorates disease in the Lewis rat adjuvant-induced arthritis model.

Adjuvant-induced arthritis (AIA) is one of many animal models of rheumatoid arthritis, a disease characterized by a T-lymphocyte and macrophage cellular infiltrate. We have characterized the development of this disease model with respect to chemokine expression. Increased levels of two chemokines, RANTES, a T-lymphocyte and monocyte chemo-attractant, and KC a chemoattractant for neutrophils, were found in whole blood and in the joint. Surprisingly, levels of MIP-1alpha, another T-lymphocyte and monocyte chemoattractant, were unchanged throughout the course of the disease in whole blood and only slightly elevated in the joint. RANTES expression plays an important role in the disease since a polyclonal antibody to RANTES greatly ameliorated symptoms in animals induced for AIA and was found to be as efficacious as treatment with indomethacin, a non-steroidal anti inflammatory. Polyclonal antibodies to either MIP-1alpha or KC were ineffective. This is the first report to show the importance of RANTES in the development of AIA.

Determination of the influence of effectivity upon residual astigmatism.

PURPOSE: A computing scheme is described which allows determination of the astigmatic contribution of ocular surface effectivity towards residual astigmatism. METHODS: This involves paraxial raytracing through astigmatic surfaces at random axes and applies the principle of astigmatic decomposition. Calculations are shown for averaged data from 66 normal right eyes. Frequency distribution graphs demonstrate individual variations. RESULTS: The averaged ratio of corneal thickness:anterior chamber:lens thickness cylinder power contributions due to effectivity (1:5:17) did not match the ratio of their respective intraocular distances (1:7:7); a disproportionate amount of astigmatism arose from lens thickness effectivity. Although previous research has revealed that results for individual eyes are prone to accummulative experimental errors, frequency distribution graphs indicate that effectivity predominantly yelds direct astigmatism (axis 180 degrees +/- 22.5 degrees). CONCLUSIONS: This computing scheme offers a means of examining the functional ocular morphology of astigmatic eyes.

Induction of RANTES expression by astrocytes and astrocytoma cell lines.

The cellular infiltrate found during the acute phase of multiple sclerosis (MS) consists of monocytes and activated T cells, suggesting the presence of cell-specific chemotactic signals during the inflammatory response. We examined the ability of human astrocytoma cell lines, as well as primary human and rat astrocytes, to generate a specific member of the intercrine/chemokine family of cytokines, RANTES, when exposed to TNF-alpha, IL-1 beta and IFN-gamma. Astrocytoma cells as well as primary astrocytes produced RANTES upon incubation with TNF-alpha or IL-1 beta. IFN-gamma alone did not induce RANTES production by astrocytes, but it potentiated the effects of either TNF-alpha or IL-1 beta. Induction of RANTES by TNF-alpha was mediated by the p55 receptor since a specific anti-p55 antiserum mimicked the effect of TNF-alpha. These results indicate that human astrocytes are capable of generating a cell-specific chemokine that can account for the inflammatory cellular infiltrate observed during the acute phase of MS, in a process that is regulated by cytokines.

Effect of added spermiophages in pooled turkey semen on fertility, embryonic mortality, and hatchability.

The semen of turkeys with numerous spermiophages was used for isolating spermiophages by density gradient centrifugation. Isolated spermiophages were suspended in Beltsville Poultry Semen Extender (BPSE) and added to semen with low spermiophage numbers to give approximate spermiophage concentrations of: 2 x 10(5)/mL (medium) and 10(6) (high). Semen with no added spermiophages was the control. Samples were diluted to 1:1 with BPSE, and for each spermiophage level (treatment), semen aliquots were either immediately inseminated or stored 6 h at 4 C with agitation (150 rpm) before insemination. Hens were inseminated weekly, and fertility, embryonic mortality, and hatchability of eggs were determined for a 10-wk period. The experiment was performed twice. In Trial 1, there were no differences in fertility between treatments except that fertility for control stored semen was lower (P < or = 0.05) than that for fresh semen (89.27 vs 95.97, respectively; SEM = 2.2). Neither hatchability nor embryonic mortality was affected by spermiophage level in Trial 1. Spermiophages did not affect fertility in Trial 2; however, hatchability for unstored treatments with added spermiophages was significantly lower than for the control. For stored semen, hatchability was significantly (P < or = 0.05) greater for treatments with added spermiophages than for the control. Differences in embryonic mortality in Trial 2 did not relate to adding spermiophages to the semen. No clearly defined detrimental effect of seminal spermiophages was shown in the present experiments.

Measurement of astigmatism arising from the internal ocular surfaces.

A method is described for measuring internal ocular surface (posterior cornea, anterior and posterior crystalline lens) astigmatism. This involves the use of videokeratography, A-scan ultrasonography, and autorefractometry along with multi-meridional phakometric measurements of Purkinje images I(anterior corneal surface) II(posterior corneal surface) and IV(posterior lens surface). Data was collected from both eyes of 66 subjects. Right and left eyes exhibited similar mean levels of astigmatism from the posterior corneal surface (R + 0.21 DC axis 82 degrees; L + 0.22 DC axis 80 degrees), anterior lens surface (R + 0.52 DC axis 8 degrees; L + 0.49 DC axis 165 degrees) and posterior lens surface (R + 1.48 DC axis 99 degrees; L + 1.16 DC axis 90 degrees). It was generally found that astigmatism arising from the anterior corneal and lens surfaces in conjunction with intraocular distance effectivity are almost completely compensated for by the posterior corneal and lens surface. Repeatability was assessed on 20 subjects. Although the methods is prone to accumulated experimental errors, these are random in nature so that the difference between repeat group averaged data never exceeded +/- 0.27 DC cylindrical component and +/- 6 degrees cylinder axis.

Plasmodium falciparum: D260, an intraerythrocytic parasite protein, is a member of the glutamic acid dipeptide-repeat family of proteins.

Members of a serologically cross-reacting family of proteins including Ag332 and Pf11.1, megadalton proteins of schizont-infected red blood cells, and gametocytes, respectively, and Pf155-RESA, a 155-kDa protein of ring-infected red blood cells, have been reported to share amino acid repeat sequences. These repeats are rich in glutamic acid dipeptides postulated to be involved in generating serologic cross-reactivity. We report the identification and characterization of another member of this cross-reacting family, a 260-kDa glutamic acid-rich intraerythrocytic protein. Human antibodies affinity purified on the 260-kDa region of Western boots of trophozoite proteins of Plasmodium falciparum were used to screen a trophozoite-stage lambda gt11 cDNA library. A 1.8-kb clone was identified and human antibodies were affinity purified on the expressing clone. Using this affinity-purified antibody and the 1.8-kb clone, the corresponding protein, its gene, and its chromosomal location were investigated. The 260-kDa corresponding protein serologically cross-reacts with Pf155-RESA, but is the product of a different gene. The 260-kDa protein is Triton X-100 soluble and is variable in molecular weight in different isolates. Immunoprecipitation of [35S]methionine-labeled infected red blood cells indicates that the protein is synthesized throughout the intraerythrocytic cycle but is most prominent in schizonts. The protein, as has been shown previously, is not immunoprecipitated from 125I surface-labeled infected red blood cells and is thus not PfEMP1, the antigen associated with cytoadherence. Indirect fluorescent antibody studies using fixed infected red blood cells suggest that the protein is localized to the periphery of the intraerythrocytic parasite.

A study of the axis of orientation of residual astigmatism.

The aim of this study was to determine the axis of orientation of residual astigmatism in a sample of human eyes applying the principle of astigmatic decomposition. Calculations were carried out on keratoscopic and refractive data collected from the right and left eyes of 70 subjects (37 male and 33 female students) of mixed race (including 25 Asians and 43 Caucasians). No statistically significant difference was found for mean levels of residual astigmatism measured in the right (0.46 DC x 98.2 degrees) and left (0.50 DC x 99.4 degrees) eyes. Residual astigmatism was predominantly against-the-rule (83% of right eyes and 66% of left eyes) and was within +/- 20 degrees of being perpendicularly disposed relative to the corneal astigmatic power axis in two thirds of the eyes measured. No statistically significant differences were found for either gender or race.

Mapping the genetic locus implicated in cytoadherence of Plasmodium falciparum to melanoma cells.

Many lines of Plasmodium falciparum undergo a deletion of the right end of chromosome 9 during in vitro cultivation accompanied by loss of cytoadherence to melanoma cells. The deletion also results in loss of expression of PfEMP1, the putative cytoadherence ligand, suggesting that PfEMP1 or a regulatory gene controlling PfEMP1 expression is encoded in this region. Initially a library of short fragments highly enriched for the right arm of chromosome 9 was constructed in bacteriophage lambda. Clones from this library were obtained randomly by the polymerase chain reaction (PCR) technique, sequenced and used to screen a yeast artificial chromosome (YAC)-P. falciparum library by PCR so that the region could be cloned and physically mapped in detail. We have used probes from this region to demonstrate that clones derived from ITG2 have undergone a deletion of intermediate length on chromosome 9. This could explain the unusual stability of cytoadherence in these clones.