P-234 AI study shows the effect of patient age on embryo quality is inherent in the morphology of an embryo

Study question

Does patient age need to be explicitly factored into AI-based embryo quality assessment, or does embryo morphology alone capture the age-related decline in embryo quality?

Summary answer

Age-related effects on embryo quality are inherently captured in embryo morphology. AI algorithms that assess morphology correlate with expected decline in embryo quality with age.

What is known already

Patient age strongly correlates with genetic aneuploidy in oocytes, which results in a dramatic reduction in genetic integrity and viability of embryos with patient age1. This negative correlation ultimately leads to poorer implantation and clinical pregnancy outcomes.

AI imaging tools assess the quality of embryos generally, using morphology alone2. However, it is unknown whether these morphological assessments inherently consider age-related quality factors like cytoplasmic and/or genetic competence, or whether age should be incorporated as a separate variable.

The current study aimed to assess the correlation of AI-based scores with the age-related decline in embryo quality.

Study design, size, duration

The study used a retrospective dataset of static Day 5 blastocyst images taken using an optical light microscope with associated PGT-A or pregnancy outcomes. The dataset comprised images of 4,000 embryos sourced from 1,199 consecutive patients treated between 2011 and 2020 at five IVF clinics (USA). The study evaluated correlation of algorithms Life Whisperer Genetics and Life Whisperer Viability with patient or donor age. Data were excluded in donor cases where age was not known.

Participants/materials, setting, methods

4,000 embryo images were used to report a linear correlation between proportion of euploids(%) and pregnancies(%) across six age-brackets, between 20 to 50 years old.

Life Whisperer Genetics AI was applied to a blind dataset of 809 images to assess likelihood of euploidy, and Life Whisperer Viability AI applied to a dataset of 556 images to assess likelihood of pregnancy. Scores within each age-bracket were averaged and chi-squared analyses was used to assess significance.

Main results and the role of chance

As expected, there was a significant negative correlation between the number of euploid embryos(%) and patient/donor age on a dataset of 4,000 images (slope of -13.2±0.2), and on a blind test set of 809 embryos (slope of -11.2±0.2). The Life Whisperer Genetics AI score was then reported on the blind test set, showing a significant negative correlation with age (-0.45±0.16 with a χ2/dof value of 0.41). The significant downward trend indicates that the AI, using morphology alone, can account for the age-related impact in the genetic competence without a corresponding reduction in accuracy, and without needing additional age-related variables in its calculation. The AI was able to generalize correctly, identifying morphological signs of ploidy well, regardless of age.

Regarding cytoplasmic or metabolic competence, we report on a blind dataset of 556 images that the proportion of viable embryos(%) reduces with increasing patient age, although exhibiting a peak in proportion of viable embryos in the 25-29 year bracket. Similarly, we show that Life Whisperer Viability AI scores within each age-bracket reduce with age.

Our results suggest that both AI algorithms for genetic competence and metabolic competence in terms of viability take into account patient age based on morphology.

Limitations, reasons for caution

Although age was shown to be represented in embryo morphology, adding a separate age-related variable could be considered in future studies. However, for embryo ranking and selection for a given patient, this is likely to be of value only when comparing embryos corresponding to different donor oocytes.

Wider implications of the findings

As the age of the patient increases, the morphology of their embryos also changes, corresponding to a decrease in embryo quality. This justifies morphology-based embryo quality assessment, giving credence to generalizable AI that perform robust assessment of embryo quality for patients of all ages, and do not require calibration.

Trial registration number

Not Applicable

AB0981 VALIDATION OF THE CAREGIVERS QUESTIONNAIRE (IMPACT OF PEDIATRIC RHEUMATIC DISEASES ON CAREGIVERS MULTIASSESSMENT QUESTIONNAIRE) IN PEDIATRIC RHEUMATIC DISEASES

Background:

The CAREGIVERS questionnaire is used as a multidimension screening instrument for burden of caregivers, it allows to examine the impact of juvenile idiopathic arthritis (JIA) on several areas of the caregiver’s life, looking for specific concerns and needs in which treatment could be required. This instrument has shown a good understanding among participants, reliability and consistency to measure the psychosocial and economic impact on primary caregivers of patients with JIA.

Objectives:

The aim of this study is to validate CAREGIVERS questionnaire with the most common pediatric rheumatic diseases, such as JIA, systemic lupus erythematosus (SLE) and juvenile dermatomyositis (JDM).

Methods:

The external validation phase of the constructed questionnaire will be carried out following Feinstein’s clinimetric and psychometrics methodology, to measure the impact of the disease on the caregiver and create a risk profile for treatment detachment.

Results:

A total of 200 questionnaires are applied to caregivers of pediatric patients with rheumatic diseases: 109 caregivers of patients with JIA, 28 caregivers of patients with DMJ and 63 caregivers of patients with SLE. When analyzing all the questions together, a general Cronbach’s alpha of 0.6751 was obtained (Table 1).

Table 1.

External validation of the Questionnaire

DimensionNumero de ÍtemsAlfa de CronbachI. Impacto Emocional60.5669II. Impacto Social30.47IIIA. Impacto Financiero40.6736IIIB. Impacto Laboral30.3151IV. Impacto Familiar50.4948V. Impacto en la Relación entre Cuidador-paciente1NAVI. Impacto en la relación de pareja1NAVII. Impacto en la Religión/Creencias/Espiritualidad1NAVIII. Impacto de las Redes Sociales40.6642Total280.6751

Conclusion:

The CAREGIVERS questionnaire showed to be validated to assess the impact of pediatric rheumatic diseases.

References:

[1]Keppeke, L.d., Molina, J., Miotto e Silva, V.B.et al.Psychological characteristics of caregivers of pediatric patients with chronic rheumatic disease in relation to treatment adherence.Pediatr Rheumatol16,63 (2018).https://doi.org/10.1186/s12969-018-0280-7

[2]Cohen EM, Morley-Fletcher A, Mehta DH, Lee YC. A systematic review of psychosocial therapies for children with rheumatic diseases. Pediatr Rheumatol [Internet]. Pediatric Rheumatology; 2017;15(1):6. Available from:http://ped-rheum.biomedcentral.com/articles/10.1186/s12969-016-0133-1.

[3]Torres-Made, M.D., Peláez-Ballestas, I., García-Rodríguez, F.et al.Development and validation of the CAREGIVERS questionnaire: multi-assessing the impact of juvenile idiopathic arthritis on caregivers.Pediatr Rheumatol18,3 (2020).https://doi.org/10.1186/s12969-020-0400-z

[4]Feinstein AR. Clinimetrics. New Haven: Yale University Press, 1987.

Disclosure of Interests:

None declared

Physical activity is increased by a 12-week semiautomated telecoaching programme in patients with COPD: a multicentre randomised controlled trial

Rationale

Reduced physical activity (PA) in patients with COPD is associated with a poor prognosis. Increasing PA is a key therapeutic target, but thus far few strategies have been found effective in this patient group.

Objectives

To investigate the effectiveness of a 12-week semiautomated telecoaching intervention on PA in patients with COPD in a multicentre European randomised controlled trial.

Methods

343 patients from six centres, encompassing a wide spectrum of disease severity, were randomly allocated to either a usual care group (UCG) or a telecoaching intervention group (IG) between June and December 2014. This 12-week intervention included an exercise booklet and a step counter providing feedback both directly and via a dedicated smartphone application. The latter provided an individualised daily activity goal (steps) revised weekly and text messages as well as allowing occasional telephone contacts with investigators. PA was measured using accelerometry during 1 week preceding randomisation and during week 12. Secondary outcomes included exercise capacity and health status. Analyses were based on modified intention to treat.

Main results

Both groups were comparable at baseline in terms of factors influencing PA. At 12 weeks, the intervention yielded a between-group difference of mean, 95% CI (lower limit – upper limit; ll-ul) +1469, 95% CI (971 to 1965) steps/day and +10.4, 95% CI (6.1 to 14.7) min/day moderate PA; favouring the IG (all p≤0.001). The change in 6-min walk distance was significantly different (13.4, 95% CI (3.40 to 23.5) m, p<0.01), favouring the IG. In IG patients, an improvement could be observed in the functional state domain of the clinical COPD questionnaire (p=0.03) compared with UCG. Other health status outcomes did not differ.

Conclusions

The amount and intensity of PA can be significantly increased in patients with COPD using a 12-week semiautomated telecoaching intervention including a step counter and an application installed on a smartphone.

Trial registration number:

NCT02158065.

Multiphoton luminescence imaging of chemically functionalized multi-walled carbon nanotubes in cells and solid tumors

A simplified scheme showing the non-linear photoluminescence properties of f-MWNTs and their potential use as imaging tools in cells and tumors.

Upregulation of voltage-gated Ca2+ channels in mouse astrocytes infected with Theiler's murine encephalomyelitis virus (TMEV)

Theiler's murine encephalomyelitis virus (TMEV) induces demyelination in susceptible strains of mice through a CD4(+) Th1 T cell-mediated immunopathological process. TMEV infection produces a syndrome in mice that resembles multiple sclerosis. In this work, we focused on the increased expression of the genes encoding voltage-gated Ca(2+) channel subunits in SJL/J mouse astrocytes infected in culture with a BeAn strain of TMEV. Affymetrix DNA murine genome U74v2 DNA microarray hybridized with cRNA from mock- and TMEV-infected astrocytes revealed the upregulation of four sequences encoding Ca(2+)-binding and Ca(2+) channel subunit proteins. The DNA hybridization results were further validated using conventional RT-PCR and quantitative RT-PCR, demonstrating the increased expression of mRNA encoding channel subunit proteins. Western blotting also showed the increased synthesis of L- and N-type channel subunit specific proteins after infection. The reduced expression and the functional upregulation of functional voltage-gated Ca(2+) channels in mock- and TMEV-infected cells, respectively, was demonstrated using voltage clamp experiments. TMEV infection in mouse astrocytes induced a Ca(2+) current with a density proportional to the amount of viral particles used for infection. The use of Ca(2+) channel blockers, nimodipine and ω-conotoxin-GVIA, showed that both functional L- and N-type Ca(2+) channels were upregulated in infected astrocytes. The upregulation of Ca(2+) channels in astrocytes after TMEV infection provides insight into the molecular processes and potential role of astrocyte Ca(2+) dysregulation in the pathophysiology of encephalomyelitis and is important for the development of novel therapeutic strategies leading to prevention of neurodegeneration.

PERK is required at the ER-mitochondrial contact sites to convey apoptosis after ROS-based ER stress

Endoplasmic reticulum stress is emerging as an important modulator of different pathologies and as a mechanism contributing to cancer cell death in response to therapeutic agents. In several instances, oxidative stress and the onset of endoplasmic reticulum (ER) stress occur together; yet, the molecular events linking reactive oxygen species (ROS) to ER stress-mediated apoptosis are currently unknown. Here, we show that PERK (RNA-dependent protein kinase (PKR)-like ER kinase), a key ER stress sensor of the unfolded protein response, is uniquely enriched at the mitochondria-associated ER membranes (MAMs). PERK(-/-) cells display disturbed ER morphology and Ca(2+) signaling as well as significantly weaker ER-mitochondria contact sites. Re-expression of a kinase-dead PERK mutant but not the cytoplasmic deletion mutant of PERK in PERK(-/-) cells re-establishes ER-mitochondria juxtapositions and mitochondrial sensitization to ROS-mediated stress. In contrast to the canonical ER stressor thapsigargin, during ROS-mediated ER stress, PERK contributes to apoptosis twofold by sustaining the levels of pro-apoptotic C/EBP homologous protein (CHOP) and by facilitating the propagation of ROS signals between the ER and mitochondria through its tethering function. Hence, this study reveals an unprecedented role of PERK as a MAMs component required to maintain the ER-mitochondria juxtapositions and propel ROS-mediated mitochondrial apoptosis. Furthermore, it suggests that loss of PERK may cause defects in cell death sensitivity in pathological conditions linked to ROS-mediated ER stress.

BDNF regulation under GFAP promoter provides engineered astrocytes as a new approach for long-term protection in Huntington's disease

Brain-derived neurotrophic factor (BDNF) is the main candidate for neuroprotective therapeutic strategies for Huntington's disease. However, the administration system and the control over the dosage are still important problems to be solved. Here we generated transgenic mice overexpressing BDNF under the promoter of the glial fibrillary acidic protein (GFAP) (pGFAP-BDNF mice). These mice are viable and have a normal phenotype. However, intrastriatal administration of quinolinate increased the number of reactive astrocytes and enhanced the release of BDNF in pGFAP-BDNF mice compared with wild-type mice. Coincidentally, pGFAP-BDNF mice are more resistant to quinolinate than wild-type mice, suggesting a protective effect of astrocyte-derived BDNF. To verify this, we next cultured astrocytes from pGFAP-BDNF and wild-type mice for grafting. Wild-type and pGFAP-BDNF-derived astrocytes behave similarly in nonlesioned mice. However, pGFAP-BDNF-derived astrocytes showed higher levels of BDNF and larger neuroprotective effects than the wild-type ones when quinolinate was injected 30 days after grafting. Interestingly, mice grafted with pGFAP-BDNF astrocytes showed important and sustained behavioral improvements over time after quinolinate administration as compared with mice grafted with wild-type astrocytes. These findings show that astrocytes engineered to release BDNF can constitute a therapeutic approach for Huntington's disease.

Human adipose tissue-derived mesenchymal stromal cells as vehicles for tumor bystander effect: a model based on bioluminescence imaging

Human adipose tissue mesenchymal stromal cells (AMSCs) share common traits, including similar differentiation potential and cell surface markers, with their bone marrow counterparts. Owing to their general availability, higher abundance and ease of isolation AMSCs may be convenient autologous delivery vehicles for localized tumor therapy. We demonstrate a model for tumor therapy development based on the use of AMSCs expressing renilla luciferase and thymidine kinase, as cellular vehicles for ganciclovir-mediated bystander killing of firefly luciferase expressing tumors, and noninvasive bioluminescence imaging to continuously monitor both, tumor cells and AMSCs. We show that the therapy delivering AMSCs survive long time within tumors, optimize the ratio of AMSCs to tumor cells for therapy, and asses the therapeutic effect in real time. Treatment of mice bearing prostate tumors plus therapeutic AMSCs with the prodrug ganciclovir induced bystander killing effect, reducing the number of tumor cells to 1.5 % that of control tumors. Thus, AMSCs could be useful vehicles to deliver localized therapy, with potential for clinical application in inoperable tumors and surgical borders after tumor resection. This approach, useful to evaluate efficiency of therapeutic models, should facilitate the selection of cell types, dosages, therapeutic agents and treatment protocols for cell-based therapies of specific tumors.

Neuroprotection by GDNF-secreting stem cells in a Huntington's disease model: optical neuroimage tracking of brain-grafted cells

The use of stem cells for reconstructive or neuroprotective strategies can benefit from new advances in neuroimaging techniques to track grafted cells. In the present work, we analyze the potential of a neural stem cell (NSC) line, which stably expresses the glial cell line-derived neurotrophic factor (GDNF) and the firefly luciferase gene (GDNF/Luc-NSC), for cell therapy in a Huntington's disease mouse model. Our results show that detection of light photons is an effective method to quantify the proliferation rate and to characterize the migration pathways of transplanted NSCs. Intravenous administration of luciferine, the luciferase substract, into the grafted animals allowed the detection of implanted cells in real time by an optical neuroimaging methodology, overpassing the limits of serial histological analyses. We observed that transplanted GDNF/Luc-NSCs survive after grafting and expand more when transplanted in quinolinate-lesioned nude mouse striata than when transplanted in non-lesioned mice. We also demonstrate that GDNF/Luc-NSCs prevent the degeneration of striatal neurons in the excitotoxic mouse model of Huntington's disease and reduce the amphetamine-induced rotational behavior in mice bearing unilateral lesions.

Metastatic behavior of human breast carcinomas overexpressing the Bcl-x(L) gene: a role in dormancy and organospecificity

The ability of metastatic cells to survive antiapoptotic signals may contribute to the organospecific-spread patterns of clinical metastasis and dormancy. MDA-MB-435 breast cancer cells (435/Bcl-x(L)), which overexpress the Bcl-x(L) gene, were labeled with the luciferase gene and injected orthotopically into homozygous athymic Balb/c (nude) mice to study the metastatic behavior of the breast cancer cells. The overexpression of Bcl-x(L) in tumors increased the overall metastatic burden in mice (bones, liver, kidneys, brain, lungs, and lymph nodes) in comparison with control tumors (435/NEO:luc) during the same time interval (ANOVA, p = 0.005). The principal differences after 110 days were found in bones, which had 1.5 x 10(5) +/- 1.2 x 10(5) tumor cell equivalents (p = 0.03), and lymph nodes, which had 7.0 x 10(6) +/- 6.0 x 10(6) tumor cell equivalents (p = 0.08). The analyses of light production by tissues at different times showed that cells from 435/NEO:luc and 435/Bcl-x(L).luc tumors were detectable in several organs by the second day after intramammary fat pad implantation. Although initially arriving at the target organs in similar numbers, 435/Bcl-x(L) cells developed more metastases than 435/Neo cells, indicating that the Bcl-x(L) gene might have a role in breast cancer dormancy, promoting survival of cells in metastatic foci. Thus, we suggest that overexpression of Bcl-x(L) could counteract the proapoptotic signals in the microenvironment and favor the successful development of metastasis in specific organs.

Interferon-gamma protects astrocytes from apoptosis and increases the formation of p21ras-GTP complex through ras oncogene family overexpression

Interferon-gamma (IFN-gamma) is a cytokine involved in the immunological activation of astrocytes. Treatment of mouse astrocytes in vitro with different doses of IFN-gamma induced changes in the basal expression of the primary response genes ras studied (H-, K-, and N-ras). H-ras is heavily transcribed in normal astrocytes, as well as in mouse brain, but its expression increases with IFN-gamma treatment. K and N-ras were poorly expressed by glial cells, although they also demonstrated a dose-dependent increase in expression after IFN-gamma treatment, with an optimal dose of 100 U/ml. As demonstrated by confocal immunocytochemistry and flow cytometry, the common protein product of the ras family, p21ras, was present in untreated cell cytoplasms and increases 169.7% in treated astrocytes. IFN-gamma treatment protects astrocytic cells from apoptosis resulting from FCS deprivation, heat-shock, or staurosporine treatment, as well as increases p21 binding of GTP. The specificity of IFN-gamma induction was demonstrated when antibodies against this cytokine completely suppressed the overinduction of ras mRNAs and, in perfect correlation, the biological effects reported above. We propose that those effects are mediated through ras oncogene family everexpression.

Adenovirus vector-directed expression of the neurotrophin-3 receptor (TrkC) in mouse astrocytes

In the present article we report the generation of a neurovirological reagent, an adenovirus vector that efficiently delivers the gene for the Neurotrophin-3 (NT-3) receptor, TrkC. Using this AdTrkC vector, we examined the induction of the expression of the above neurotrophin receptor in pure cultures of mouse astrocytes, a glial cell type that does not constitutively express this gene. Infection of astrocytes at an optimal dose of 100-200 plaque forming units (p.f.u.) per cell, induced expression of specific mRNA, as demonstrated by RT-PCR and Northern blot. This mRNA was translated to produce a mean of 20,157 biologically active receptor molecules per astrocyte with a Kd of 4.1 x 10(-11) M, as demonstrated by 125I-NT-3 binding. After 2D electrophoresis, the mature glycoprotein and some precursors were recognised by antibodies raised against the carboxy-terminal peptide of Trk. Binding of the ligand induced autophosphorylation ofTrkC and 3H-thymidine incorporation in transduced cells. These results demonstrate that our AdTrkC vector efficiently mediates the expression of high-levels of biologically active NT-3 receptors.

Metastatic burden in nude mice organs measured using prostate tumor PC-3 cells expressing the luciferase gene as a quantifiable tumor cell marker

BACKGROUND

Sensitive procedures for quantitative measurement of tumor cell spread as a function of time and primary tumor size are necessary to generate models of metastasis and formulate therapies.

METHODS

Prostate carcinoma cells PC-3.luc expressing the luciferase gene were intramuscularly inoculated in nude mice to generate experimental tumors. Metastatic cells in target organs were easily counted by their capacity to produce light.

RESULTS

Tumor cells were very mobile and migrated to all the target organs examined: lymph nodes, brain, bone, lungs, liver, kidney, spleen, testicles, prostate, seminal vesicle, and scrotum. Organ colonization started very early, 14 days after inoculation, when primary tumors were very small and produced an amount of light equivalent to that generated by 2 x 10(4) tumor cells in vitro (tumor cell equivalents, TCEs). Tumor cell burden could be quantitatively described by power functions of time or primary tumor light-producing capacity. The ratio of metastatic TCEs to primary tumor TCEs clustered around organ characteristic values: 10(-3) for femur and lumbar lymph nodes, 10(-6) for the spleen, and 10(-3) for the added set of organs.

CONCLUSIONS

Dispersal of PC-3 tumor cells from IM experimental tumors started early before the third week postinoculation and when primary tumors had 2 x 10(4) TCEs. Tumor cells were found widely spread in all the organs tested. The possibility of easily quantifying tumor cell burden should make this approach useful for the study of metastasis and the development of antimetastatic therapies.

Interferon-gamma induces proliferation but not apoptosis in murine astrocytes through the differential expression of the myc proto-oncogene family

Interferon-gamma (IFN-gamma) is a cytokine mainly secreted by activated T-lymphocytes. Treatment of mouse astrocytes in vitro with IFN-gamma augmented the basal expression of the primary response proto-oncogenes c-myc and L-myc as detected by Northern blotting. Such inductions were maximal at doses of 10 U/ml and after 60 min of treatment. Astrocytes fully differentiated in vitro do not express N-myc mRNA nor are induced to express it by exposure to IFN-gamma. As demonstrated by flow cytometry, the common protein product of the myc family was present in the nucleus of the cells. The specificity of IFN-gamma induction was demonstrated when antibodies against IFN-gamma completely suppressed the overinduction of these mRNAs. No apoptotic death can be detected in astrocytes treated with IFN-gamma at doses that induce c-myc expression. Conversely, treatment with a dose of 10 U/ml induced cells proliferation in astrocytic cells as measured by (3)H-thymidine incorporation.

Theiler's murine encephalomyelitis virus infection induces early expression of c-fos in astrocytes

We have determined whether Theiler's murine encephalomyelitis virus (TMEV), a picornavirus that produces demyelination in genetically susceptible strains of mice, induces c-fos in pure quiescent cultures of mouse brain astrocytes. As observed in Northern blots, the expression of this immediate early gene increases in a dose-dependent manner, with its expression peaking at a multiplicity of infection of 100. The expression of c-fos is transient, peaking after 30 min and disappearing 2 h after infection. The virus is quickly internalized at 37 degrees C upon binding to its specific receptor located at the cell surface and is actively replicated in the cytoplasm of the astrocytes, as demonstrated by FACS flow cytometry. Using the same technique, nuclear translation of c-fos mRNA is also shown. The specificity of viral induction is demonstrated by its neutralization with TMEV-specific antibodies and by the fact that only viral particles and not purified protein components VP1, VP2, and VP3 induced proto-oncogene expression. This rapid induction of c-fos in astrocytes could be the first stage in the infection of these central nervous system cell populations by TMEV. The biological relevance of these findings is assessed by the demonstration of c-fos activation after viral infection in vivo.

Traffic to lymph nodes of PC-3 prostate tumor cells in nude mice visualized using the luciferase gene as a tumor cell marker

Tumor cell traffic between intramuscular tumors experimentally induced in nude mice and lymph nodes was studied using PC-3.luc prostate adenocarcinoma cells permanently transfected with the luciferase gene as a tumor cell marker. This sensitive approach allowed the detection of 1 luminescent tumor cell mixed with 1 x 10(7) unlabeled PC-3 cells and of 1 tumor cell/lymph node. PC-3.luc cells inoculated in nude mice showed a 1000-fold expansion, accompanied by a 4.5-fold increase in tumor cell density (tumor cell number/gram of tumor), during the first 90 days of primary tumor growth. No macroscopic secondary tumors were found in organs, other than lymph nodes, by the end of the experiment. Tumor cell spread to lymph nodes was detected at Day 21, when there were 2 x 10(5) tumor cells at the inoculation sites, before discrete primary tumors could be identified. The total tumor cell burden in the tested lymph nodes was modeled by a power function of primary tumor cell number (determination coefficient R2 = 0.9472). By the end of the experiment, on Day 110, there were 1.8 metastatic cells in the studied lymph nodes for every 1000 primary tumor cells. These results suggest that empirically obtained tumor-specific indexes could be used to characterize the invasion of lymph nodes by tumor cells. The path of spread for PC-3.luc cells from intramuscular sites appears to follow the lymphatic system, and at no time during the experiment were tumor cells found in blood. An upper limit of no more than 16 blood-circulating tumor cells was established for these experiments. The observation of tumor cells that were invading the lymphatic system from the onset of tumor growth but unable to establish secondary tumors in other organs emphasizes the potential of this procedure in studying the multi-step nature of metastasis.

Intracellular expression of Fc gamma RIII (CD16) and its mobilization by chemoattractants in human eosinophils

We characterized the existence, translocation, and reabsorption during cellular activation of a constitutively expressed intracellular CD16 in the human eosinophil. By two-color flow cytometry, we showed that 6.5+/-0.3% of nonpurified eosinophils expressed surface CD16. After digestion with phosphatidylinositol-specific phospholipase C, surface CD16 on both neutrophils and eosinophils decreased substantially, suggesting that eosinophil CD16 is a glycosyl-phosphatidylinositol-linked isoform. However, CD16 was substantially expressed intracellularly in human eosinophils. Epitope-specific binding to CLB-gran11 mAb from non-NA2/NA2 donors demonstrated that intracellular eosinophil CD16 also differed from the transmembrane isoform of CD16 expressed on NK cells or macrophages. Western blot analysis performed with 3G8 or DJ130c mAb showed a broad band at approximately 65 to 80 kDa, which was the same as neutrophil CD16 from the same NA2/NA2 donors. Upon stimulation by chemoattractants C5a, FMLP, or platelet-activating-factor, eosinophilic intracellular CD16 was rapidly translocated to the eosinophil surface, expressed maximally at 30 s, and then gradually disappeared from the cell surface during the next 10 min. Intracellular flow cytometry of stimulated eosinophils and sandwich ELISA of stimulated eosinophil supernatants demonstrated that the disappearance was due to its rapid release into medium and reabsorption by the cells. Our data identify a CD16B that is consistently expressed intracellularly but only rarely on the surface of nonactivated human eosinophils. This CD16 is transiently expressed during stimulation by chemoattractants.

Application of the continuity equation and valve resistance to the evaluation of St. Jude Medical prosthetic aortic valve dysfunction

Doppler echocardiography was applied to the assessment of patients with surgically documented St. Jude medical aortic valve dysfunction. Derivation of effective orifice area and Doppler velocity index with the continuity equation and calculation of valve resistance accurately differentiated stenotic from regurgitant and normal valves.

Mouse astrocytes store and deliver brain-derived neurotrophic factor using the non-catalytic gp95trkB receptor

A study of the brain-derived neurotrophic factor (BDNF)-binding capacity of pure astrocytes demonstrated that these cells bind and endocytose [125I]BDNF rapidly using the gp95trkB truncated receptor. A linear Scatchard plot indicated the presence of only one type of receptor that bound the ligand, with a low Kd of 1.24 x 10(-8) M. There were an average of 36,468 copies of this receptor on untreated astrocytes. Interestingly, the neurotrophin was not degraded intracellularly, as demonstrated by HPLC experiments. Furthermore, the stored molecule was released by a mechanism regulated by the extracellular BDNF concentration as a bioactive neurotrophic molecule that supports neuron survival, in a time- and temperature-dependent manner. The data demonstrate that astrocytes exert an active role in the bioavailability of this neurotrophin, which is further enhanced in an inflammatory-like situation induced experimentally in culture using interferon-gamma.

Interferon-gamma induces the expression of immediate early genes c-fos and c-jun in astrocytes

The expression of the proto-oncogenes, c-fos and c-jun, in cultured mouse astrocytes and its induction by the potent astrocyte activator interferon-gamma (IFN-gamma), were examined by Northern blot and flow cytometry. Both proto-oncogenes were induced in a dose-dependent manner, peaking around 100 U/ml of IFN-gamma. The kinetics of expression is very transient for c-fos, reaching a maximum at 30 min and decreasing rapidly thereafter. The c-jun remained high throughout the stages analysed. Cycloheximide superinduced c-fos and c-jun induction by IFN-gamma, thus indicating that both act as immediate early genes. The products of c-fos and c-jun, proteins FOS and JUN, that act in conjunction forming the regulatory factor AP-1, were detected 1 hr after stimulation in virtually all cells, using flow cytometry. The induction in astrocytes of both proto-oncogenes could be the first stage of immunological activation of these central nervous system cells by immune interferon.

Quantitation of the cytosolic phospholipase A2 (type IV) in isolated human peripheral blood eosinophils by sandwich-ELISA

Sandwich enzyme-linked immunosorbent assay (sELISA) was developed for precise quantitation of cytosolic phospholipase A2 (cPLA2 type IV) concentration in isolated human peripheral blood eosinophils as an alternative to semiquantitative chemiluminescent assay employing immunoprecipitation/Western blot analysis. In this assay, monoclonal mouse anti-human cPLA2 antiserum was used as the capture antibody, polyclonal rabbit anti-human cPLA2 antiserum as the secondary antibody, and alkaline phosphatase-conjugated goat anti-rabbit IgG as the tertiary, reporter antibody. Purified human cPLA2 (0-1000 ng/ml) dissolved in Tris-HCl buffered saline was used as the standard protein. The detection limit for cPLA2 in 10(6) eosinophils was 0.109 ng/ml, and coefficients of inter- and intra-assay variation were 4.23% and 7.07%, respectively. There was no cross-reactivity with other (secretory) isoforms of PLA2 (sPLA2 types I-III) either from porcine pancreas, human synovial fluid, or bee venom. In separate studies, the recovery of cPLA2 was > 83% when eosinophil lysate was supplemented exogenously with two different concentrations of cPLA2. From a total protein content of 22.3 +/- 1.7 micrograms/10(6) cells, the baseline concentration of cPLA2 was 0.38 +/- 0.18 ng/10(6) cells in eosinophils obtained from mildly atopic donors. Immunoblotting studies confirmed the complete specificity for the type IV isoform as detected by sELISA. This sELISA method permits the precise quantitative assessment of cPLA2 in nanogram quantities per million cells, which has not previously been possible by immunoblotting analysis.

Overexpression of basal c-fos and c-jun but not of ras oncogenes after Theiler's murine encephalomyelitis virus infection of glial cells

Constitutive expression of the cellular proto-oncogenes c-fos and c-jun, and in a lesser extent ras, was demonstrated in the glioma cell line C-6 by flow cytometry analysis using specific mono and polyclonal antibodies. Basal expression of the products of the early response genes c-fos and c-jun were increased 66 and 50% when Theiler's murine encephalomyelitis virus (TMEV) infected these cells. No increase in ras transcription could be demonstrated after infection. This activation follows a kinetic reaching maximum values after 60 min and was proportional to the multiplicity of infection used. The described effect was completely abrogated by rabbit antibodies to TMEV but was not altered by normal rabbit serum. Furthermore, an intact infectious virion is needed to detect this effect. Fetal calf serum and lipopolysaccharide stimulation slightly increases c-fos and c-jun expression following a slower kinetics. Cytokine treatment (IL-1 alpha, IL-6, IFN-gamma and TNF alpha), did not induce oncogene over-expression. Therefore, this stimulation seems to be linked to the TMEV infectious process.

Expression of interferon-gamma receptors on murine oligodendrocytes and its regulation by cytokines and mitogens

Interferon-gamma (IFN-gamma) is a cytokine known to exert an important immunological role on astrocytes and oligodendrocytes. As a receptor for IFN-gamma has been demonstrated on murine astrocytes, we have searched for a specific receptor on the cell surface of pure mouse oligodendrocytes maintained in tissue culture. Using recombinant murine IFN-gamma labelled with 125I, we have established the basic physicochemical parameters of the binding. A single receptor was found with a Kd of 1 x 10(-9) M. The number of receptors per cell was 3000-4000 and its molecular weight, as determined by cross-linking experiments, is 87,000. The binding of IFN-gamma to its oligodendrocyte receptor is saturable, specific and temperature-dependent. The receptor-IFN-gamma complex is quickly endocytosed at 37 degrees (the half-time of maximal internalization is around 1 min). Some cytokines, such as interleukin-1 alpha and interleukin-6, up-regulated the expression of the oligodendrocyte receptor, but others, such as tumour necrosis factor-alpha, did not. A dramatic increase in receptor expression is induced by lipopolysaccharide but it is not detectable after treatment with concanavalin A.

The receptor for tumor necrosis factor on murine astrocytes: characterization, intracellular degradation, and regulation by cytokines and Theiler's murine encephalomyelitis virus

Previous reports have shown that tumor necrosis factor (TNF) exerts a role on the physiology of astrocytes under inflammatory situations. The signalling for biological effects of this and other cytokines are usually exerted through cell surface receptors. In this study, we have demonstrated the presence of a surface TNF alpha receptor type I in murine astrocytes of both SJL/J and BALB/c origin, using 125I-labelled recombinant mouse TNF alpha. A linear Scatchard plot indicates the presence of only one type of receptor with a MW of 58 kDa (Type I TNF receptor) that binds the ligand with a Kd of 1 x 10(-9) M. There are 3,000 copies of this receptor on untreated astrocytes. The results also indicate that receptor-bound TNF is rapidly internalized at 37 degrees C and degraded intracellularly to a principal molecular species which elutes from HPLC reverse-phase columns at 38% acetonitrile rather than at 60%, as native TNF alpha does. The binding is up-regulated by increasing the number of receptors (but not its affinity) by treatments with Theiler's murine encephalomyelitis virus (TMEV), Con A and inflammatory cytokines such as IL-1 alpha, IL-6, and INF-gamma. It is not influenced by vaccinia virus, IL-2, or LPS. This receptor may contribute to the initiation of perpetuation of the immune response which mediates the demyelinating inflammation induced by Theiler's virus.

Demonstration of the presence of an interleukin-1 receptor on the surface of murine astrocytes and its regulation by cytokines and Theiler's virus

Interleukin-1 (IL-1) binding found in rodent brain, and its biological effect on astroglial cells, suggests that the receptor for IL-1 alpha may be located on astrocytes. A radioligand receptor assay performed on pure mouse astrocyte cultures revealed the presence of one binding site [type I, molecular weight (MW) 80,000], with Kd = 0.3 x 10(-1) M), at a density of 150 receptors/cell. The specific, saturable and displaceable high-affinity binding took place in a time- and temperature-dependent way. The receptor-IL-1 alpha complex was quickly endocytosed at 37 degrees but not at 4 degrees. The receptor expression was up-regulated by Theiler's virus, interferon-gamma, tumour necrosis factor and IL-6; was not affected by vaccinia virus infection; and decreased after lipopolysaccharide treatment.

Interleukin-6 production by brain tissue and cultured astrocytes infected with Theiler's murine encephalomyelitis virus

Theiler's murine encephalomyelitis virus (TMEV) is known to interact with cells of the central nervous system (CNS). Here we report that, interestingly, it is a potent inductor of interleukin-6 (IL-6) in the CNS of infected animals and in pure cultures of astrocytes. Maximal IL-6 gene transcription in glial cells, as detected by bioassay and ELISA, was observed at 6 and 24 h after infection. Astrocytes from both SJL/J and Balb/c (strains of mice susceptible and resistant, respectively, to TMEV-induced demyelination) produced similar amounts of IL-6, measured in tissue culture supernatants. These results indicate that although an immunomodulatory effect can be exercised by IL-6 synthesized by astrocytes, it does not play a crucial role in immune-mediated demyelination induced by TMEV.

Differential IL-1 synthesis by astrocytes from Theiler's murine encephalomyelitis virus-susceptible and -resistant strains of mice

Increasing evidence shows that interleukin-1 (IL-1) contributes to inflammatory processes, such as experimental allergic encephalomyelitis (EAE) and virus-induced demyelination, inside the central nervous system (CNS). Using primary cultures of mouse astrocytes, we show that these glial cells can be induced to produce IL-1 alpha when infected with Theiler's murine encephalomyelitis virus (TMEV). This was true for astrocytes from SJL/J mice, a strain susceptible to TMEV-induced demyelination. Conversely, BALB/c astrocytes, derived from animals genetically resistant to demyelination, did not produce IL-1 alpha in detectable amounts. Therefore, a differential IL-1 gene expression, which is strain specific, is demonstrated after TMEV infection in astrocytes. The release of IL-1 alpha by SJL astrocytes was studied from kinetic, infectivity, and immunochemical points of view. Since IL-1 plays a critical role in the immune response, its production by astrocytes in some strains of mice may contribute to virus-induced susceptibility and to inflammation associated with this experimental model of multiple sclerosis.

Structure, expression, and evolution of guinea pig serum amyloid P component and C-reactive protein

The structure and expression of the pentraxins, serum amyloid P component (SAP), and C-reactive protein (CRP), have been investigated in the guinea pig. Northern blot analysis of hepatic RNA from animals in which acute inflammation had been induced by intraperitoneal injection of thioglycollate established that neither SAP or CRP is a major acute phase reactant in the guinea pig. Genomic clones of SAP and CRP were isolated and sequenced, and the gene and the derived protein sequences were compared with other mammalian homologues. Both genes have organizations typical of the pentraxin genes of other species, but some differences were defined in the regions that potentially determine the capacity of the pentraxin gene to be induced during acute inflammation. Nucleotide substitutions in coding regions have occurred at similar rates in the two pentraxin genes. Nonsynonymous substitution rates indicate that SAP and CRP are subject to similar, relatively low levels of constraint; at the amino acid sequence level the rate of evolution is approximately two replacements per site per 10(9) years. An estimate of the phylogenetic relationship among the pentraxin genes suggests that SAP and CRP arose as the result of a gene duplication event that occurred very early in mammalian evolution, but subsequent to the divergence of the reptilian ancestors of the mammalian and avian lineages. This raises doubts about the identity of proteins from fish, which have been previously characterized as CRP and SAP.

Theiler's murine encephalomyelitis virus induces tumour necrosis factor-alpha in murine astrocyte cell cultures

Cytokines have been postulated to exert an important modulatory and recruiting role in demyelination induced by Theiler's murine encephalomyelitis virus (TMEV) in SJL/J mice. Using a cytolytic bioassay and ELISA, we have detected and quantified a cytokine, tumour necrosis factor-alpha (TNF-alpha), in supernatants from astrocyte cultures infected in vitro with TMEV. TNF was detected only after TMEV-specific infection of astrocyte cultures (approximately 200-400 U/ml). In vitro TNF synthesis appeared in a dose- and time-dependent manner and was produced by both SJL/J (a strain susceptible to TMEV-induced demyelination) and BALB/c (a resistant strain) astrocytes. The precise nature of TNF activity was further assessed by fast protein liquid chromatography (FPLC) and antibody neutralization. These results indicate an active role for astrocytes as accessory immune cells in our experimental model for multiple sclerosis.

Demonstration of the presence of a specific interferon-gamma receptor on murine astrocyte cell surface

Interferon gamma (IFN-gamma) is a pleiotropic lymphokine produced by T-lymphocytes which acts as a soluble mediator in immunological reactions. In addition to several immune target cells, such as monocytes and macrophages, it acts on the principal glial population, the astrocytes, inducing Ia antigen expression. We have developed a binding assay for 125I-labeled recombinant murine IFN-gamma, and show that, using this assay, IFN-gamma interacts with a single specific receptor on the murine astrocyte cell membrane. The binding is specific and saturable and it takes place with a Kd = 1.64 x 10(-9) M, with 11,100 receptor molecules per astrocytic cell. The binding shows, as for macrophages, species specificity. Using an immune assay including rabbit antibodies to IFN-gamma and 125I-labeled protein A, we have demonstrated an internalization of the ligand. This is an energy-dependent process, as around 50% of the bound IFN-gamma is endocytosed after 4 h at 37 degrees C when cultures are maintained in complete culture medium.

IL-1, IL-2 and IFN-gamma production by Theiler's virus-induced encephalomyelitic SJL/J mice

Interleukins have been postulated to exert an important modulatory and recruiting role in the Theiler's murine encephalomyelitis virus (TMEV)-induced demyelination of the central nervous system (CNS) in SJL/J mice. Using bio- and radioimmunoassays, we have detected and quantified some of the interleukins suspected to play a role in this immune-mediated process. The interleukins 1 and 2 (IL-1, IL-2) and interferon-gamma (IFN-gamma) have been measured in homogenates from the CNS and sera from infected animals, as well as in supernatants from antigen-specific in vitro-stimulated spleen and meningeal cells. IL-1 was detected both in CNS tissue homogenates (approximately 20-40 fmol/ml) and in splenic cultures (200 U/ml). IL-2 was detected only after TMEV-specific antigenic stimulation in spleen cultures (approximately 120 U/ml). In vitro, IL-2 and IL-1 synthesis appear in a dose- and time-dependent manner. IFN-gamma could not be found in any case. The precise nature of IL-1 and IL-2 activity was further assessed by HPLC. The above results strongly indicate the presence of functionally active macrophages in the CNS infiltrates of cells triggering this autoaggressive immune process. In addition, we propose a central role for IL-1 in augmenting the intracerebral immune response leading to the inflammatory demyelination induced by TMEV.

Characterization of the specific meningeal T cell response to intracerebral inoculation of Theiler's murine encephalomyelitis virus

The presence of a resident T lymphocyte population in the meninges of normal SJL/J mice has been detected by the use of the T cell-specific mitogen concanavalin A. Optimal conditions for [3H]thymidine incorporation were studied. An antigen-specific meningeal T cell proliferative response in SJL/J mice, primed by intracerebral inoculation of Theiler's murine encephalomyelitis virus, was also detected. This response indicated that leptomeningeal mononuclear cell infiltrations are involved in the immune response that triggers the demyelinating disease.

Theiler's murine encephalomyelitis virus-binding activity on neural and non-neural cell lines and tissues

Three categories of cell lines are described with respect to their activity in binding Theiler's murine encephalomyelitis virus (TMEV). High, medium and low densities of viral receptors can be detected on cell lines from different species and origins by using an immunological binding assay. Nevertheless, TMEV acts as a fastidious virus that only infects a few cell types productively. No correlation between virion binding and degree of permissiveness to infection could be detected. The presence of viral receptors in both susceptible and resistant strains of mice seemed to have a widespread tissue distribution, the thymus being an exception. When primary cerebral cultures, enriched in neurons, astrocytes or oligodendrocytes, were checked in the immunological assay, a higher density of viral receptors was detected in the neuronal population. The number of virus-binding sites in the BHK-21 cell line is reported here to be 5 x 10(3) per cell; approximately 15 x 10(3) and 2.5 x 10(3) are the estimates of binding sites per cultured neuron and macroglial cell, respectively.

Lack of cross-reaction between myelin basic proteins and putative demyelinating virus envelope proteins

No cross-reaction could be detected between purified myelin basic proteins (MBP) from mouse, rat or human origins and envelope proteins of viruses suspected of inducing demyelinating processes. In the experimental model using Theiler's murine encephalomyelitis virus, competition radioimmunoassay failed to detect any cross-reaction between MBP and VP1, VP2 and VP3 envelope antigens. In the human situation, antibodies against SV5 and measles viruses, both etiologically linked with multiple sclerosis, also failed to recognize MBP. These results rule out molecular mimicry as a cause of demyelination.

Characterization of the immune response to intracerebral inoculation of Theiler's murine encephalomyelitis virus: fine protein specificity of the splenic T cell and humoral antibody response

The spleen T cell proliferative response of SJL/J mice primed by intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) was characterized in vitro. A dose-response [3H]thymidine incorporation was found with TMEV, but not with unrelated viruses. The maximum response was obtained at doses of 5 X 10(5) cells per well with cultures of 96 h duration. Viral capsid proteins VP1 and VP2 carried the antigenic determinants for the T cell response, VP3 playing no role in the in vitro cellular immune response. The antibody synthesis showed the same antigenic specificity as the cellular one, as only antibodies against VP1 and VP2 could be found in the sera of the immunized animals.

Antibodies against Drosophila potassium channels identify membrane proteins across species

Shaker is a complex locus (ShC) in Drosophila that encodes components of the K+ channel responsible for the IA current. We have raised antibodies against synthetic peptides of selected sequences from the Sh products. One of the antisera identifies a 71 kDa protein band in immunoblots from Drosophila neural membrane proteins. We demonstrate that this protein is encoded within the viable (V) region of the ShC since deletions and breakpoints in this part of the complex eliminate this band from the immunoblots. Certain Sh mutations abolish the production of this product while other do not seem to interfere with it. The same antiserum identifies bands of different apparent molecular weight (Mr) in membrane extracts of nervous systems of a variety of organisms including vertebrates.

Receptors for Theiler's murine encephalomyelitis virus: characterization by using rabbit antiviral antiserum

An immunological assay was developed to characterize the binding of Theiler's murine encephalomyelitis virus to BHK-21 cell receptors. After absorption of the virus and formaldehyde fixation, rabbit antibodies and Staphylococcus aureus protein A labeled with 125I formed a specific complex on the surfaces of the cells. The optimal multiplicity of infection in this system was 10 PFU per cell. The virus was internalized at 33 and 37 degrees C, but internalization did not take place at 25 or 4 degrees C. The binding was proportional to the number of cells and was significant within 30 s. Cell surface receptors were still active after fixation, and only intact viruses were bound, as demonstrated by the lack of binding of the purified, isolated virion proteins VP1, VP2, and VP3.

Quantitative and qualitative congenital deficiency of antithrombin III: a new molecular variant called ATIII-Barcelona 2

A Spanish family with a quantitative-qualitative antithrombin III (ATIII) deficiency and thrombotic tendency is reported. The qualitative defect was suggested by the crossed immunoelectrophoresis (CIE) in the presence of heparin in plasma of all those affected. However, the crossed immunoelectrofocusing (CIEF) showed the same ATIII pattern in controls and affected members. Two populations of ATIII were detected by affinity chromatography on heparin-sepharose from affected members' plasma. The ATIII unbound to sepharose beads was devoid of heparin cofactor activity and showed a lack of anodal migration in CIE in the presence of heparin. The ATIII eluted corresponded to normal ATIII. Our data supports the view that an abnormal ATIII molecule is present in all affected family members in the heterozygous state. This is the first reported ATIII variant in which a molecular abnormality produces a lack of affinity for heparin but no changes in its isoelectric point. This familial ATIII deficiency was named ATIII- Barcelona 2.