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Biomedical subjects

M Blank

Publications and source records attributed to M Blank.

At least 37 records · Page 2Linked to original sources
PubMed2003

Antiprothrombin antibodies are associated with pregnancy loss in patients with the antiphospholipid syndrome.

OBJECTIVE: To document the clinical association between the history of pregnancy loss in patients with the diagnosis of primary or secondary antiphospholipid syndrome (APS) and the presence of different antiprothrombin antibody subtypes [immunoglobulin G (IgG), IgM and IgA] in a cohort of patients with APS. METHODS: Records of 170 female patients with primary APS, or APS secondary to systemic lupus erythematosus (SLE) or secondary to other autoimmune diseases were studied. RESULTS: In female APS patients with IgG antiprothrombin antibodies (n = 105) significant associations to pregnancy loss (p < 0.0001), early pregnancy loss (p < 0.0001) and a negative association to thrombocytopenia (p < 0.01) could be identified. In the group of patients with IgG antiprothrombin antibodies and at least one pregnancy (n = 84) a significant association with pregnancy loss (p < 0.005) and especially with early pregnancy loss (p < 0.0001) was demonstrated. No association with other immunoglobulin subtypes of antiprothrombin antibodies could be documented. In the subgroup of patients with primary APS and at least one pregnancy in the history, pregnancy loss (p < 0.005) and early pregnancy loss (p < 0.0001) were found to be highly associated with the presence of IgG antiprothrombin antibodies. IgG antiprothrombin antibodies represent the highest independent risk factor for pregnancy loss with an odds ratio of 4.5. There was no statistically significant association with venous or arterial thrombosis in all IgG antiprothrombin antibody positive patients. CONCLUSION: The results of this study document the association of IgG antiprothrombin antibodies with pregnancy loss and in particular early pregnancy loss in a large and well-characterized cohort of patients. We would recommend routine testing for antiprothrombin antibodies in young female patients with APS.

Abortion, Spontaneous↗
PubMed2003

Anti-prothrombin antibodies cause thrombosis in a novel qualitative ex-vivo animal model.

Anti-prothrombin antibodies (aPT) are associated with thrombotic manifestations, and their association with reproductive failure is debatable. The aim of this study was to examine whether aPT could induce thrombosis and other clinical manifestations of the anti-phospholipid syndrome (APS). Mice were immunized with either prothrombin, beta2-glycoprotein-I (beta2GPI), or beta2GPI followed by prothrombin. The presence of clinical manifestation of APS, including thrombocytopenia, lupus anticoagulant and fetal resorption rates, was evaluated in all mice groups compared with nonimmunized mice. Thrombosis was studied in a novel ex-vivo model in which the aorta was sutured for 1 min and the presence or absence of visible thrombus was qualitatively evaluated. Immunized mice developed high autoantibody levels directed towards their immunizing autoantigens. The groups immunized with beta2GPI or beta2GPI/prothrombin, but not with prothrombin alone, developed prolonged aPTT, thrombocytopenia and increased fetal resorption rate. All prothrombin-immunized mice as well as most beta2GPI/prothrombin-immunized mice developed visible thrombus within the aorta. Some beta2GPI immunized mice developed very mild thrombus. None of the CFA/PBS-injected or the nonimmunized mice developed such thrombus. Active immunization with prothrombin or beta2GPI/prothrombin is associated with prothrombotic activity of blood in an ex-vivo model. This is the first direct evidence for thrombus induction by aPT.

Animals↗
PubMed2003

The prevalence of coeliac disease antibodies in patients with the antiphospholipid syndrome.

High prevalence of coeliac disease (CD) has been reported in various autoimmune disorders, buthas not been studied in the antiphospholipid syndrome (APS). We aimed to establish the prevalence of CD antibodies in a cohort of APS patients, and to examine whether CD may be responsible for some of the manifestations of APS. Fifty-seven patients (47 females, 10 males) with APS were studied for clinical manifestations and serological markers of the disease, as well as the presence of anti-endomysial antibodies using an ELISA assay (EMA-ELISA). Control subjects were 171 healthy individuals, age- and sex-matched (141 females). Eight patients with APS (14%, six females) were found to have EMA-ELISA antibodies, compared with 2/141 (1.1%) of controls (P = 0.0003). Antibodies against beta2-glycoprotein-I (beta2GPI) epitopes (GRTCPKPDDLP) were more prevalent in EMA-positive patients than in EMA-negative patients (P = 0.006). Vasculitic skin lesions were significantly more common in EMA-ELISA-positive compared with EMA-ELISA-negative patients(62.5 versus 16.3%, P = 0.01). Among the skin manifestations, superficial cutaneous necrosis (37.5 versus 2%, P = 0.007) was more prevalent in EMA-ELISA-positive than in EMA-ELISA-negative patients. EMA-ELISA antibodies are common in APS, and their presence is associated with high prevalence of antibodies recognizing certain beta2-glycoprotein epitopes, and with cutaneous manifestations of APS.

Adult↗
PubMed2003

TNFalpha DNA vaccination prevents clinical manifestations of experimental antiphospholipid syndrome.

Naked DNA encoding TNFalpha was introduced to BALB/c mice with experimental antiphospholipid syndrome (APS) induced by beta2GPI. Administration of naked DNA encoding TNFalpha resulted in the generation of immunological memory to its gene product, associated with elevated circulating anti-TNFalpha antibodies. Enriched IgG fraction of the mouse anti-TNFalpha was biologically active since it prevented endothelial cell activation by TNFalpha e.g., inhibition of monocyte adhesion to activated endothelial cells (HUVEC). Mice immunized with beta2GPI, vaccinated with TNFalpha DNA at an early stage of disease development, showed decreased titres of circulating anti-beta2GPI antibodies as compared to the group of mice vaccinated with a control naked DNA. The reduction of antiphospholipid antibody production was followed by amelioration of the foetal loss, increased platelet count to normal values as well as normalization of the prolonged aPTT. APS mice which were introduced to the TNFalpha DNA vector at a later stage of the disease development, showed less improvement in their clinical manifestations. The current study suggests a way in which a DNA vaccine can be employed for induction of a protective immunity in experimental APS.

Animals↗
PubMed2003

The effects of antiphospholipid antibodies obtained from women with SLE/APS and associated pregnancy loss on rat embryos and placental explants in culture.

Recurrent fetal loss occurs in approximately 1% of women. Autoimmune causes have been suggested as a factor in some of these cases. High rates of intrauterine fetal growth retardation and increased incidence of prematurity is associated with systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). We found in previous studies that sera from SLE/APS patients when used as a culture medium for rat embryos were found to reduce embryonic growth and development, induce a high rate of embryonic anomalies and death and damage the yolk sac morphologically and functionally. In order to investigate the direct effect of IgG purified from women with SLE/APS on the growth and viability of embryos, we cultured 11.5-day-old rat embryos in their yolk sacs in the presence of IgG purified from SLE/APS patients with recurrent pregnancy loss (RPL). The IgG affected directly the embryo and yolk sac, reducing their growth. The purified IgG positive for anticardiolipin/anti-DNA antibodies reduced yolk sac and embryonic growth more than sera negative for these antibodies but positive for antiphosphatydilserine and for antilaminin. Monoclonal antiphosphatydilserine reduced yolk sac growth but the embryos remained intact. Following the observed damage to the yolk sac we cultured human placental explants at 5.5-8 weeks of pregnancy in sera from SLE/APS patients for 96 hours and found that these sera reduced placental trophoblastic cell growth, reduced their proliferation rate and increased their rate of apoptosis. Successful treatment of the women resulted in a correction of the damage induced in the cultured rat embryos and in the cultured placental explants.

Abortion, Habitual↗
PubMed2003

Neuronal-binding antibodies from patients with antiphospholipid syndrome induce cognitive deficits following intrathecal passive transfer.

Antiphospholipid antibodies (aPL) have been suggested to play a role in causing cognitive and behavioral impairments. In the present study we investigated the pathogenic potential of aPL by intracerebro-ventricular (ICV) administration of immunoglobulins (IgG) from patients with antiphospholipid syndrome (APS). IgG, purified from the sera of four APS patients, was tested for binding to normal mouse brain by immunohistological staining. These IgG (7.5 microg) were injected ICV unilaterally to male C3H mice. Mice injected with IgG purified from pooled sera derived from healthy subjects served as controls. The mice were examined neurologically for motor function and coordination, and cognitively in a Morris water maze. The cognitive tests were performed with the experimenter blinded to the treatment. The performance of the mice in four separate experiments was compared by analysis of variance with repeated measures. IgG from one APS patient was found to bind best to neuronal structures in the hippocampus and cerebral cortex. Mice (n = 43) injected with this IgG performed worse in the water maze compared to the controls (n = 45) with significant effects of the aPL IgG on the overall performance of the mice (treatment, P < 0.03), on learning throughout the experiment (treatment x day, P < 0.02) and on short term memory (treatment x day xtrial, P < 0.002). IgG injected from two of the three other patients also bound specifically to mouse brain neurons and produced an impairment in performance of the water maze. These results support the hypothesis that aPL that gain access to the central nervous system may play a direct role in the pathogenesis of neurological manifestations of APS.

Adult↗
PubMed2003

Anti-cardiolipin and anti-beta2-glycoprotein I (beta2GP-I) antibody assays as screening for anti-phospholipid syndrome.

BACKGROUND: Antiphospholipid antibodies are a family of autoantibodies that exhibit a broad range of target specificities and affinities, all recognizing various combinations of phospholipids, phospholipid binding proteins or both. OBJECTIVE: To evaluate the frequency of anticardiolipin (aCL) or anti-beta-2 glycoprotein I (anti-beta2GPI) antibodies in a cohort of patients with primary (PAPS) and secondary (SAPS) antiphospholipid syndrome and other rheumatic and infectious conditions. METHODS: Sera were drawn from 226 patients with PAPS (n= 66), SAPS (n= 60), rheumatoid arthritis (RA) (n= 30), scleroderma (SSc) (n= 30) or syphilis (n= 30). IgG, IgM, IgA aCL and anti-beta2GPI antibodies were determined for all patients. We employed Varelisa diagnostic kits (Pharmacia Diagnostics GmbH & Co.KG, Germany). RESULTS: In APS patients: aCL and anti-betaGP1 antibodies were detected in 81.8% and 70% in PAPS and SAPS patients, respectively. In PAPS, aCL were detected in 71.2%, and anti-beta2GP1 in 50% of patients. In SAPS, aCL were detected in 63.3%, and anti-beta2GP1 in 53.3% of patients. In syphilis, aCL and anti-beta2GP1 antibodies were detected in 46.7% of patients in low levels: aCL in 36.7% and anti-beta2GP1 in 20% of patients. aCL antibodies were detected in 10%, 13.3%, and 0% of RA patients, SSc patients, and healthy persons, respectively. Anti-beta2GP1 antibodies were not detected in RA patients, SSc patients, and healthy persons. CONCLUSIONS: aCL and anti-beta2GP1 antibodies are more frequently found in sera of APS patients, and can be found in low levels in syphilis. Anti-beta2GP1 assay found to be more specific than aCL in antiphospholipid antibodies determination.

Antiphospholipid Syndrome↗
PubMed2002

Reliability of causes of death in persons with Type I diabetes.

AIMS/HYPOTHESIS: To compare causes of death assessed by a clinical review committee, the information given on death certificates, and ICD-codes provided by the State Documentation Office in deceased persons with Type 1 (insulin-dependent) diabetes mellitus. METHODS: A cohort of 3674 patients were monitored for 10+/-3 (mean +/- SD) years. Vital status and end-stage diabetic complications were documented for 97%; 251 patients had died. Causes of death were assessed by a clinical review committee and compared to the information provided by death certificates and ICD-9 codes. RESULTS: The review committee defined a leading cause of death in 94% of cases, whereas death certificates were available for 73% and ICD-codes for 79% of patients; 10% of death certificates could not be evaluated due to insufficient information. Diabetes was mentioned on 71% of death certificates, and renal disease in 75% of cases with renal replacement therapy. There was acceptable agreement between the committee, death certificates and ICD-codes only for deaths due to neoplasma, and between the committee and death certificates for deaths due to acute myocardial infarction, cerebrovascular events and accidents. In only one out of four deaths due to hypoglycaemia and in four of seven deaths due to ketoacidosis was this diagnosis mentioned on the death certificate. No death due to hypoglycaemia or ketoacidosis and 41% due to suicide were identifiable by ICD-codes. CONCLUSION/INTERPRETATION: Reliance on death certificates or ICD-codes as the only sources of information on the cause of specific mortality does not provide data of sufficient reliability for evaluation of clinical outcome in Type I diabetes.

Adult↗
PubMed2002

Immunization of naive BALB/c mice with human beta2-glycoprotein I breaks tolerance to the murine molecule.

OBJECTIVE: Immunization of naive mice with beta2-glycoprotein I (beta2GPI) leads to the generation of pathogenic anticardiolipin antibodies associated with clinical manifestations of the antiphospholipid syndrome (APS). The aim of this study was to determine whether immunization of naive mice with human beta2GPI, which shares homology with mouse beta2GPI molecules, breaks tolerance to murine beta2GPI and leads to the generation of anti-mouse beta2GPI. METHODS: Twenty-four female BALB/c mice were immunized in the footpads with 10 microg of human beta2GPI. Twelve age- and sex-matched BALB/c mice were immunized in the same manner with Freund's complete adjuvant and served as controls. The reactivity of whole sera, polyclonal IgG, and affinity-purified anti-beta2GPI IgG antibodies against human, bovine, and mouse beta2GPI was evaluated by enzyme-linked immunosorbent assay. RESULTS: High titers of anti-human beta2GPI IgG antibodies were detected 1 month after immunization. Progressively increasing titers against murine and bovine beta2GPI were recorded 1-4 months after injection. CONCLUSION: Immunization of mice with human beta2GPI resulted in the generation of antibodies reacting with human, bovine, and murine beta2GPI. The loss of tolerance to mouse beta2GPI is attributable to the high interspecies homology of beta2GPI. These results may point to molecular mimicry as a possible cause of APS.

Animals↗
PubMed2002

Molecular diversity of the dystrophin-like protein complex in the developing and adult avian retina.

Mutations in dystrophin cause muscular dystrophy but also affect the CNS, including information processing in the retina. To better understand the molecular basis of these CNS deficits, we analyzed the molecular composition and developmental appearance of dystrophin and of the dystrophin-associated protein complex (DPC) in the embryonic and adult avian retina. We detected a concentration of the DPC at the vitreal border and in the outer plexiform layer of the adult retina. At both locations the complex had a different molecular composition and different developmental expression pattern. At the vitreal border, the complex was composed of utrophin, alpha-dystrobrevin-1, and dystroglycan, and was present at all stages of retinal development even before neurogenesis and gliogenesis. On the other hand, the complex in the outer plexiform layer consisted of dystrophin, beta-dystrobrevin and dystroglycan. The distribution of this complex changed from a diffusely distributed to an aggregated form during development concomitant with synapse formation in the outer plexiform layer. Solubilization of the retinal extracellular matrix by intravitreal injection of collagenase resulted in a redistribution of the complex at the retinal vitreal border but had no influence on the distribution of the dystrophin-associated proteins in the outer plexiform layer. These results demonstrate two types of dystrophin-like complexes in the chick retina with differential molecular compositions, different anchorage to the extracellular matrix, and different developmental expression patterns, suggesting distinct functions for the DPC at both locations.

Aging↗
PubMed2002

The effects of IgG purified from women with SLE and associated pregnancy loss on rat embryos in culture.

PROBLEM: Recurrent fetal loss occurs in approximately 1% of women. Autoimmune causes have been suggested as a factor in some of these cases. High rates of intrauterine fetal growth retardation and increased incidence of prematurity is associated with systemic lupus erythematosus (SLE) and the anti-phospholipid syndrome (APS). Autoantibodies from sera of SLE/APS patients affect reproductive outcome in pregnant mice, as was studied in vivo, where injection of immunoglobulin (Ig)G purified from patients with APS to mice caused fetal resorptions and growth retardation. METHODS: In order to investigate the direct effect of IgG purified from women with SLE or APS on the growth and viability of embryos, we cultured 11.5-day old-rat embryos in their yolk sacs in the presence of IgG purified from SLE and APS patients. RESULTS: IgG purified from SLE and recurrent pregnancy loss (RPL) patients affected directly the embryo and yolk sac reducing their growth. The purified IgG positive for anti-cardiolipin/anti-DNA antibodies reduced yolk sac and embryonic growth more than sera negative for these antibodies. CONCLUSION: Various antiphospholipid antibodies affect differently the growth and development of the embryo and the placenta.

Animals↗
PubMed2002

The role of anti-endothelial cell antibodies in Kawasaki disease - in vitro and in vivo studies.

Kawasaki disease (KD) is a systemic vasculitis with cardiac and noncardiac complications. Anti--endothelial cell antibodies (AECA) are found among many patients with KD. The aim of this study was to investigate the pathogenic role of AECA in KD using in vitro and in vivo experimental models. F(ab)2 fragments of IgG-AECA and IgM-AECA were affinity purified from a patient with active KD. Their endothelial binding and ability to induce a pro-adhesive and a pro-inflammatory phenotype were evaluated in vitro. Twenty Balb/C mice were immunized with KD-AECA or with control Ig (N-Ig) to induce AECA in a murine model by the idiotypic manipulation method. Both KD-AECA isotypes bind significantly to human umbilical vein endothelial cell (HUVEC) compared to N-Ig. The in vitro activity was demonstrated by the antibodies ability to activate endothelial cells resulting in increased IL-6 secretion, adhesion molecule expression and monocytic cell line (U937) adherence to HUVEC. Five of the mice that received KD-AECA developed murine AECA after 3 months. None of the mice that received N-Ig produced AECA. The murine AECA increased monocyte adhesion to EC in vitro, similarly to the AECA used for immunization. Furthermore, all the mice that developed AECA had proteinuria and IgG deposition in the renal mesangium. No histological or immunofluorescence evidence of cardiac vasculitis could be detected. AECA might play a role in the emergence of some of KD manifestations.

Animals↗
PubMed2002

Behavioral and cognitive deficits occur only after prolonged exposure of mice to antiphospholipid antibodies.

The antiphospholipid (Hughes) syndrome (APS) includes systemic and central nervous system (CNS) pathology associated with antibodies to a complex of phospholipids and beta2-glycoprotein I (beta2-GPI). Beta2-GPI immunized mice develop systemic manifestations of APS and we presently examined CNS manifestations in this APS model. Female BALB/c mice were immunized once with beta2-GPI in complete Freund's adjuvant (CFA) or with CFA alone (controls). A staircase test and a T-maze alternation test were performed to test behavior and cognition in independent groups of mice 6, 12 and 18 weeks following the immunization. The APS mice developed elevated levels of antibodies against negatively charged phospholipids and beta2-GPI. Neurological impairment was detected only 18 weeks after the induction of the APS and consisted of both cognitive (53 +/- 4 vs 71 +/- 3% correct choices in the T-maze alternation for APS vs control mice, P < 0.001) and behavioral changes (higher number of rears (18 +/- 2 vs 11 +/- 1, P < 0.006) and higher number of stairs climbed (12 +/- 2 vs 7 +/- 1, P < 0.02). This is the first report of cognitive deficits in this APS model and demonstrates the time course for the development of previously described behavioral changes. The mechanism involved in these CNS manifestations remains to be elucidated.

Animals↗
PubMed2001

Electromagnetic acceleration of electron transfer reactions.

The Moving Charge Interaction (MCI) model proposes that low frequency electromagnetic (EM) fields affect biochemical reactions through interaction with moving electrons. Thus, EM field activation of genes, and the synthesis of stress proteins, are initiated through EM field interaction with moving electrons in DNA. This idea is supported by studies showing that EM fields increase electron transfer rates in cytochrome oxidase. Also, in studies of the Na,K-ATPase reaction, estimates of the speed of the charges accelerated by EM fields suggest that they too are electrons. To demonstrate EM field effects on electron transfer in a simpler system, we have studied the classic oscillating Belousov--Zhabotinski (BZ) reaction. Under conditions where the BZ reaction oscillates at about 0.03 cycles/sec, a 60 Hz, 28 microT (280 mG) field accelerates the overall reaction. As observed in earlier studies, an increase in temperature accelerates the reaction and decreases the effect of EM fields on electron transfer. In all three reactions studied, EM fields accelerate electron transfer, and appear to compete with the intrinsic chemical forces driving the reactions. The MCI model provides a reasonable explanation of these observations.

Biochemical Phenomena↗
PubMed2001

Systematic evolution of a DNA aptamer binding to rat brain tumor microvessels. selective targeting of endothelial regulatory protein pigpen.

Tumor microvessels differ in structure and metabolic function from normal vasculature, and neoangiogenesis is associated with quantitative and qualitative changes in expression of endothelial proteins. Such molecules could serve as molecular addresses differentiating the tumor vasculature from those of the normal brain. We have applied Systematic Evolution of Ligands by EXponential enrichment (SELEX) against transformed endothelial cells as a complex target to select single-stranded DNA-ligands (aptamers) that function as histological markers to detect microvessels of rat experimental glioma, a fatal brain tumor that is highly vascularized. Both the SELEX selection procedure as well as subsequent deconvolution-SELEX were analyzed by fluorescence based methods (flow cytometry and fluorescence microscopy). Of 25 aptamers analyzed, one aptamer was selected that selectively bound microvessels of rat brain glioblastoma but not the vasculature of the normal rat brain including peritumoral areas. The molecular target protein of aptamer III.1 was isolated from endothelial cells by ligand-mediated magnetic DNA affinity purification. This protein was identified by mass spectrometry as rat homologue of mouse pigpen, a not widely known endothelial protein the expression of which parallels the transition from quiescent to angiogenic phenotypes in vitro. Because neoangiogenesis, the formation of new blood vessels, is a key feature of tumor development, the presented aptamer can be used as a probe to analyze pathological angiogenesis of glioblastoma. The presented data show that pigpen is highly expressed in tumor microvessels of experimental rat brain glioblastoma and may play an important role in warranting blood supply, thus growth of brain tumors.

Animals↗
PubMed2001

Regulating genes with electromagnetic response elements.

A 900 base pair segment of the c-myc promoter, containing eight nCTCTn sequences, is required for the induction of c-myc expression by electromagnetic (EM) fields. Similarly, a 70 bp region of the HSP70 promoter, containing three nCTCTn sequences, is required for the induction of HSP70 expression by EM fields. Removal of the 900 base pair segment of the c-myc promoter eliminates the ability of EM fields to induce c-myc expression. Similarly, removal of the 70 bp region of the HSP70 promoter, with its three nCTCTn sequences, eliminates the response to EM fields. The nCTCTn sequences apparently act as electromagnetic field response elements (EMRE). To test if introducing EMREs imparts the ability to respond to applied EM fields, the 900 bp segment of the c-myc promoter (containing eight EMREs) was placed upstream of CAT or luciferase reporter constructs that were otherwise unresponsive to EM fields. EMREs-reporter constructs were transfected into HeLa cells and exposed to 8 microT 60 Hz fields. Protein extracts from EM field-exposed transfectants had significant increases in activity of both CAT and luciferase, compared with identical transfectants that were sham-exposed. Transfectants with CAT or luciferase constructs lacking EMREs remained unresponsive to EM fields, i.e., there was no increase in either CAT or luciferase activity. These data support the idea that EMREs can be used as switches to regulate exogenously introduced genes in gene therapy.

Base Sequence↗
PubMed2001

Electromagnetic initiation of transcription at specific DNA sites.

Initiation of transcription by electromagnetic (EM) fields offers an insight into mechanism. EM field stimulated transcription appears to require specific DNA sequences, and these bases may be sites where EM fields generate large repulsive forces between chains by accelerating electrons that move within DNA. We can estimate the repulsion between chains by assuming that electron affinity is a measure of electron density at each base, and inversely related to the velocity of electrons (and the force). The repulsive force can be compared to the attraction between chains due to H-bonds. From the difference between repulsion and attraction, we show that sites rich in C and T, as in the specific sequences, would be more likely to come apart in EM fields. These calculations suggest a plausible mechanism for initiation of transcription by EM fields, and provide a rationale for specific sequences to function as EM field response elements. Electron flow could also be a factor in DNA chain melting due to Joule heating.

Base Sequence↗