Anti-cancer activities of hypericin in the dark

The potent photodynamic properties of hypericin (HY) elicit a range of light-dependent virucidal and tumoricidal activities. Yet, a relatively low reduction/oxidation potential endows HY with electron accepting and donating properties enabling it to act as both an oxidizing and a reducing agent. HY can thus compete as an electron acceptor from bioenergized reduction/oxidation reactions generating its excitation energy for biological activities from physiological reduction/oxidation reactions in the absence of light. Our studies show that HY can inhibit the growth of highly metastatic murine breast adenocarcinoma and squamous cell carcinoma tumors in culture. Furthermore, we show that HY can interfere with the growth of these tumors in mice reducing tumor size and prolonging animal survival in complete absence of light. While there is no evidence that HY induces apoptosis in these cells in the dark, 3H-thymidine incorporation into DNA was significantly reduced indicating effects that are apparently cytostatic in nature compared to the cytocidal effects of HY with light.

Induction and treatment of the antiphospholipid syndrome--lessons from animal models

The diagnosis of antiphospholipid syndrome (APS) is based on a combination of clinical and serological criteria. This review summarizes the literature regarding animal models of APS. Animal models of this syndrome help to elucidate pathogenic roles of the characteristic antiphospholipid antibodies in pregnancy morbidity, vascular thrombosis, neurologic disease and atherosclerosis. Furthermore, these models also provide measures to evaluate novel therapies for APS. These include bone-marrow transplantation, intravenous immunoglobulin, anticoagulation, interleukin-3, in addition to other therapies. Experimental induction and treatment of APS largely contributes to our understanding of the disease and to better management of its clinical characteristics.

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.

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.

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.

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.

Optimal frequencies for magnetic acceleration of cytochrome oxidase and Na,K-ATPase reactions

Low frequency magnetic fields increase the activity of the membrane enzymes, Na,K-ATPase and cytochrome oxidase, and the increased activity varies with frequency. Optimal frequencies for increases in the reaction rate constant of cytochrome oxidase and in the rate of splitting of ATP by Na,K-ATPase differ by an order of magnitude, and are in the ranges of the turnover numbers of the respective enzyme reactions. The two frequency dependence curves are similar in that the slope of the low frequency portion is about 10 times greater than the slope of the high frequency portion. The greater slope indicates greater ability to adjust quickly in the low frequency range, which may be significant for optimal biological control of activity.

The association between anti-thyroid antibodies and pregnancy loss

The incidence of thyroid autoantibodies in women with recurrent fetal loss, infertility or women who miscarried appears to be increased compared with controls of reproductive age without previous abortions. There are few working hypotheses concerning the asociation between anti-thyroid antibodies and the increased risk for pregnancy loss. The first hypothesis suggests that women with high titers of anti-thyroid antibodies have underlying very mild thyroid "under function". Another theory views the anti-thyroid antibodies as simply secondary markers of a predisposition of autoimmune disease rather than the actual cause of pregnancy loss. An evolutionary explanation suggests that reproductive problems in women with high titers of autoantibodies exist in order to prevent the transmission of autoimmune genes to the next generation. The reason for the association between pregnancy loss and thyroid immunity is still not clear. The working hypotheses above supply multi-factorial explanations, which could act together, may even be in synergy, as the propulsion for the pregnancy loss. Until today the mechanism by which anti Tg are responsible for pregnancy loss is not clear. Induced animal models with high titier of anti Tg could provide direct evidence for the pathogenic role of anti-thyroid antibodies and the mechanism that is responsible for the pregnancy loss in autoimmune thyroiditis. In the current presentation we describe data concerning the association between anti-thyroid antibodies and pregnancy loss, and hypothesis which explains this association.

Autoantibodies to oxidized low-density lipoprotein in coronary artery disease

BACKGROUND

The significance of antioxidized low-density lipoprotein (oxLDL) antibodies in atherogenesis is not yet clear, and there are conflicting data regarding anti-oxLDL levels in early hypertension.

METHODS

The levels of anti-oxLDL antibodies were studied in coronary artery disease patients with (n = 82) or without (n = 36) hypertension, in association to other risk factors for coronary artery disease.

RESULTS

The levels of anti-oxLDL antibodies did not differ significantly between coronary artery disease patients with or without hypertension. (0.132 +/- 0.146 v 0.153 +/- 0.158 optical density at 405 nm, respectively; P = .48). No significant differences in anti-oxLDL antibodies were found between men and women with and without hypertension, between hypertensive patients with normal and abnormal blood pressure measurements, and between medicated and nonmedicated hypertensive patients. The presence of diabetes mellitus, smoking, and hypercholesterolemia, either solely or in combination, did not result in significant differences in antibody levels in the hypertensive or normotensive patients.

CONCLUSIONS

Although the levels of oxLDL antibodies might be modified in early hypertension, once advanced coronary artery disease has developed the presence of hypertension does not affect anti-oxLDL levels.

Anti-endothelial cell antibodies from patients with thrombotic thrombocytopenic purpura specifically activate small vessel endothelial cells

Thrombotic thrombocytopenic purpura (TTP) is an uncommon disease of an unknown etiology, characterized by consumptive thrombocytopenia, microangiopathic hemolytic anemia, fever and acute thrombotic complications, especially within the cerebral circulation. Although anti-endothelial cell antibodies (AECA) have occasionally been shown to be present in TTP, their role in the pathogenesis of the disease has never been ascertained. In the current study we demonstrated the pathogenic activity of affinity-purified anti-endothelial cell F(ab)2 antibodies (AECA/TTP) from four consecutive patients with active TTP. These AECA/TTP bound to and activated only microvascular endothelial cells (EC) and not large vessel EC. The specificity of AECA/TTP binding to microvascular EC was confirmed by competition assay employing membranes derived from small and large vessels EC. Activation included enhanced IL-6 and von Willebrand factor release from the EC followed by increased expression of adhesion molecules P-selectin, E-selectin and vascular cell adhesion molecule-1 on the EC, as evaluated by ELISA. Increased expression of adhesion molecules was followed by an increase in monocyte adhesion to EC. The level of soluble thrombomodulin (TM) also increased in the culture medium of activated microvascular EC upon exposure to AECA/TTP antibodies and was directly correlated to a decrease in cell-associated TM. Our data suggest that AECA/TTP directed against microvascular EC could play a pathogenic role in the development of endothelial injury in TTP that leads to thrombosis.

Coronary calcium and anti-cardiolipin antibody are elevated in patients with typical chest pain

The aim of this study was to examine whether detection of coronary calcium and the autoimmune response associated with atherosclerosis, either solely or in combination, are different in patients with typical and atypical chest pain. Coronary calcium as detected by spiral computerized tomography and levels of antibodies against cardiolipin (CL), oxidized low-density lipoprotein (ox-LDL), and beta2-glycoprotein-I (beta2-GPI) were studied in patients with typical chest pain (n = 52), atypical chest pain (n = 19), or without chest pain (n = 21). Patients with typical chest pain had higher mean levels of coronary calcium (expressed as natural transformation of total coronary calcium score) compared with patients with atypical chest pain and controls (5.04 vs 3.21 and 2.75, respectively; p < 0.001). The levels of anti-CL were (mean +/- SD of optical density multiplied by 1,000): 262 +/- 140, 170 +/- 82, and 230 +/- 115 for patients with typical chest pain, atypical chest pain, and controls, respectively (p = 0.016). No significant difference was found between groups regarding anti-ox-LDL and anti-beta2-GPI autoantibody levels. In the typical chest pain group, there was a higher prevalence of high total coronary calcium scores (p = 0.03) and high anti-CL levels (p = 0.01) than in the atypical chest pain group. Eighteen of 52 patients with typical chest pain (35%) had both high calcium scores and high antibody levels, whereas none of the 19 patients (0%) who had atypical chest pain had high levels of both (p = 0.003). A combination of both coronary calcium and anti-CL was associated with higher area under the receiver operator characteristic curves than for each separately. High coronary calcium scores or high anti-CL levels are found more often in typical than in atypical chest pain patients, but a combination of high levels of both can better differentiate typical from atypical chest pain patients.

Linseed oil suppresses the anti-beta-2-glycoprotein-I in experimental antiphospholipid syndrome

The immunomodulatory potential of a diet enriched with n-3 polyunsaturated fatty acids was analysed in naïve mice with experimental antiphospholipid syndrome (APS) induced by active immunization with H-3, a human anti-beta-2-glycoprotein-I (anti-betaGPI) monoclonal antibody (mAb). Fetal loss and other clinical manifestations of APS were prevented in the group of APS mice upon exposure to the enriched n-3 diet compared to the control group. The titers of anti-betaGPI were significantly lower (in O.D. at 405 nm, 1.387+/-0.232 in comparison to non-treated mice 0.637+/-0. 111, P< 0.05). The reduced titer of anti-betaGPI antibodies in the sera of the treated mice was associated with a reduced number of anti-betaGPI forming cells in cultured splenocytes (84+/-14, antibody-forming cells (AFC)/10(5)cells in comparison to 37+/-4 AFC/10(5)cells (P< 0.02).In addition to the suppression of the humoral response in mice with experimental APS fed with linseed oil, we also observed an inhibitory effect on the cellular response. The T-cell response to anti-betaGPI was lower in comparison to mice immunized with H-3 anti-betaGPI mAB, which were kept on a normal diet. These results indicate that polyunsaturated fatty acids may improve clinical and laboratory parameters of APS. The beneficial effects of diets enriched with n-3 should be further examined as a potential mode of therapy for patients with APS.

Ciprofloxacin affects pregnancy loss in CBA/JxDBA/2J mice possibly via elevation of interleukin-3 and granulocyte macrophage-colony stimulating factor production

PROBLEM

The mechanisms mediating pregnancy loss are far from being understood, but it is believed that modulation of the maternal immune system, that is known to support pregnancy, might serve as a means for the treatment of habitual abortions. Thus, we examined the effect of the anti bacterial agent ciprofloxacin, which was shown to affect maternal immunoreactivity, on pregnancy loss in the resorption-prone CBA/JxDBA/2J mouse combination as well as associated changes in Interleukin (IL)-3 and Granulocyte macrophage-colony stimulating factor (GM-CSF) production.

METHOD OF STUDY

CBA/J females mated to DBA/2J males were treated with ciprofloxacin for 5 consecutive days. On day 15 of pregnancy, the number of resorbed embryos was recorded and IL-3 mRNA expression as well as IL-3 and GM-CSF protein production by splenocytes were assayed by northern blotting and ELISA, respectively.

RESULTS

Ciprofloxacin treatment resulted in a significant reduction in the resorption rate as compared to the effect of the control antibiotic ceftazidime or PBS only, while not affecting the number of implantation sites/mouse. Also, splenocytes from ciprofloxacin-treated CBA/J mice exhibited an increased level of IL-3 mRNA transcripts as well as an elevation in IL-3 and GM-CSF protein production.

CONCLUSIONS

Our data demonstrate the ability of ciprofloxacin to reduce pregnancy loss in the CBA/JxDBA/2J mouse model, possibly via elevation of IL-3 and GM-CSF production.

Prognosis of persons with type 1 diabetes on intensified insulin therapy in relation to nephropathy

OBJECTIVE

To study the prognosis of persons with type 1 diabetes in relation to the degree of nephropathy at initiation of intensified insulin therapy.

DESIGN

Ten years follow-up of a cohort of 3674 patients who had participated in a 5-day group treatment and teaching programme for intensification of insulin therapy between September 1978 and December 1994.

SETTING

Ten diabetes centres in Germany.

SUBJECTS

A total of 3674 patients (insulin treatment before age 31), age at baseline 27 +/- 10 years, with a diabetes duration of 11 +/- 9 years. Patients were divided into three groups according to baseline renal parameters (group I, normal proteinuria, n = 1829; group II, microproteinuria, n = 1257; group III, at least macroproteinuria, n = 367).

MAIN OUTCOME MEASURES

End-stage diabetic complications (blindness, amputations, renal replacement therapy, standardized mortality ratios (SMR) and causes of death.

RESULTS

Outcome measures were documented for 97% of patients; 251 (7%) had died. During follow-up, 1% of patients in group I, 4% in group II and 47% in group III had at least one end-stage diabetic complication. SMR for men: nephropathy group I, 2.2 (95% CI = 1.5-3); group II, 3.2 (2.3-4.3); group III, 11.5 (8.8-14.7). SMR for women: group I, 2.5 (1.5-3.8); group II, 3.5 (2.2-5.3); group III, 27 (19.8-35.9). Causes of death for men and women combined: group I (total 58 deaths)--cardiovascular, 21 (36%); hypoglycaemia, 1; ketoacidosis, 3; violent deaths, 17 (29%); others, 16; group II (66 deaths)--cardiovascular, 25 (38%); hypoglycaemia, 2; ketoacidosis, 2; violent deaths, 14 (21%); others, 23; group III (114 deaths)--cardiovascular, 68 (60%); hypoglycaemia, 2; ketoacidosis, 5; infections, 15 (13%); violent deaths, 5 (4%); others, 19.

CONCLUSIONS

Patients with microproteinuria have only a slightly worse prognosis than patients with normal proteinuria during the first 10 years after initiation of intensified insulin therapy. Excess mortality amongst patients who started intensified insulin therapy is mainly due to those with manifest clinical nephropathy.

Dissociation of the dystroglycan complex in caveolin-3-deficient limb girdle muscular dystrophy

Limb girdle muscular dystrophy is a group of clinically and genetically heterogeneous disorders inherited in an autosomal recessive or dominant mode. Caveolin-3, the muscle-specific member of the caveolin gene family, is implicated in the pathogenesis of autosomal dominant limb girdle muscular dystrophy 1C. Here we report on a 4-year-old girl presenting with myalgia and muscle cramps due to a caveolin-3 deficiency in her dystrophic skeletal muscle as a result of a heterozygous 136G-->A substitution in the caveolin-3 gene. The novel sporadic missense mutation in the caveolin signature sequence of the caveolin-3 gene changes an alanine to a threonine (A46T) and prevents the localization of caveolin-3 to the plasma membrane in a dominant negative fashion. Caveolin-3 has been suggested to interact with the dystrophin-glycoprotein complex, which in striated muscle fibers links the cytoskeleton to the extracellular matrix and with neuronal nitric oxide synthase. Similar to dystrophin-deficient Duchenne muscular dystrophy, a secondary decrease in neuronal nitric oxide synthase and alpha-dystroglycan expression was detected in the caveolin-3-deficient patient. These results implicate an important function of the caveolin signature sequence and common mechanisms in the pathogenesis of dystrophin-glycoprotein complex-associated muscular dystrophies with caveolin-3-deficient limb girdle muscular dystrophy.

Cytoprotection by electromagnetic field-induced hsp70: a model for clinical application

A unique approach to clinical application of cytoprotection is offered by electromagnetic (EM) field induction of stress proteins. EM fields are noninvasive and easily applied, as compared with the current hyperthermia protocols. Fertilized dipteran eggs and cultured rodent cardiomyocytes (H9c2 cells) were used as models to test EM fields for their ability to induce increased hsp70 levels for effective cytoprotection. Eggs preconditioned with an 8 microT 60Hz EM field for 30 min had 114% increase in hsp70 levels, and an average 82% increase in survival, following a lethal temperature of 36.5 degrees C. Thermal preconditioning at 32 degrees C was not nearly as effective in dipteran eggs, inducing only a 44% increase in survival. Preconditioning of cultured murine cardiomyocytes (H9c2 cells) with an 8 microT 60 Hz field induced a 77% average increase in hsp70 levels.

Pathogenic role of anti-endothelial cell antibodies in systemic vasculitis

Antiendothelial cell antibodies (AECA), a heterogeneous group of antibodies quite distinct from the ANCA family, have been detected in variety of diseases which share a varying degree of vessel wall damage. This review is mainly focused on Wegener's granulomatosis, Takayasu's arteritis and Kawasaki syndrome, which provide the best examples to evaluate the pathogenic and prognostic value of AECA. There is increasing evidence to show that AECA might be pathogenic in inducing autoimmune vascular disease. It is relevant to note that the presence and titre of AECA has been correlated with disease activity in systemic vasculitis. Experimental in vitro and in vivo models support a potential pathogenic role for AECA in sustaining immune-mediated vessel inflammation. Rather than being cytotoxic to endothelial cells, AECA are able to up-regulate the expression of adhesion molecules (E-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) and to induce the secretion of cytokine and chemokine which, in turn, cause leukocyte recruitment and adhesion. A recent idiotypic animal model has provided further evidence that AECA can be pathogenic.

Immunomodulation of experimental autoimmune diseases via oral tolerance

The concept of oral tolerance refers to a form of peripheral tolerance in which mature lymphocytes in the peripheral lymphoid tissues are rendered nonfunctional or hyporesponsive by prior oral administration of an antigen. The primary mechanisms mediating oral tolerance include deletion, anergy of antigen-specific T cells and active cellular suppression, the primary determining factor being the dose of fed antigen. Low doses favor active suppression, whereas high doses favor deletion and anergy. Active cellular suppression is mediated by the induction of regulatory T cells in the gut-associated lymphoid tissue, which migrate to the systemic immune system. One of the primary mechanisms of active cellular suppression is via secretion of suppressive cytokines such as TGF-beta, IL-4, and IL-10 following antigen-specific triggering. TGF-beta is produced both by CD4+ and CD8+ GALT-derived T cells and is an important mediator of the active suppression component of oral tolerance. CD4+ cells that primarily produce TGF-beta appear to be a unique T-cell subset and termed Th3 cells. Oral tolerance was successfully studied in a variety of experimental models for autoimmune diseases, among them experimental autoimmune encephalomyelitis, experimental arthritis, experimental anti-phospholipid syndrome, experimental autoimmune uveoretinitis, experimental insulin dependent diabetes mellitus (IDDM), and experimental autoimmune myasthenia gravis. The results obtained in experimental animal models have led to the conduction of several clinical trials of oral tolerance in patients with multiple sclerosis, rheumatoid arthritis, uveitis, and IDDM. Conflicting results were obtained, and although some improvement has been noted in some of the patients, broad ranging clinical improvement has not yet been observed. A more accurate choice of antigens, as well as more precise dosing and timing of antigen-administration might lead to better results in the future.

Anti-cardiolipin antibody from a patient with antiphospholipid syndrome (APS) recognizes only an epitope expressed by cardiolipin/beta 2-glycoprotein-I (beta 2GPI) complex and induces APS

OBJECTIVE

As the antiphospholipid syndrome (APS) is characterized by antibodies which bind negatively charged phospholipids either directly or mainly through different target epitopes located on the beta-2-glycoprotein-I (beta 2GPI) molecule, the aim of this study is to describe an additional target epitope for anti-cardiolipin binding.

METHODS

The binding characteristics of affinity purified anti-cardiolipin antibodies from a patient with monoclonal gammopathy associated with clinically overt APS were studied; inhibition studies were also carried out. These antibodies were used for the active induction of experimental APS.

RESULTS

The affinity purified anti-cardiolipin antibodies were found to bind a target epitope created by the complex of cardiolipin/beta 2GPI, while not reacting with a complex composed by another phospholipid (phosphatidylserine/beta 2GPI), as confirmed by direct binding and competition assays. Immunization of naive mice with this unique affinity purified anti-cardiolipin antibody resulted in the induction of experimental APS (thrombocytopenia, prolonged coagulation timed and fetal resorptions). The anti-cardiolipin/beta 2GPI injected mice developed high titers of mouse anti-cardiolipin/beta 2GPI antibodies with the same binding characteristics as the human antibody which was used for disease induction.

CONCLUSION

APS is a unique syndrome that is characterized by a diversity of pathogenic anti-phospholipid antibodies which may explain the diversity of clinical manifestations reported in patients.

Anti-beta 2-glycoprotein I antibodies and anti-endothelial cell antibodies induce tissue factor in endothelial cells

Anti-beta 2-glycoprotein I antibodies bind to endothelial cells through beta 2-GPI. The antibodies are present in patients with systemic lupus erythematosus and antiphospholipid syndrome and are associated with the pathogenesis of the disease. Anti-endothelial cell antibodies that react with constitutive antigens on ECs are present in patients with vasculiditis and other diseases. Both types of antibodies can activate ECs. Frequent findings in APLS and vasculitis are fibrin deposits and thromboembolic phenomena. These indicate that the coagulation system is activated. However, the mechanism of activation is not clear. ECs generate tissue factor upon stimulation with various substances. In the present study we report that monoclonal anti-beta 2-GPI antibodies and AECAs, derived from a patient with primary APLS and a patient with Takayasu's arteritis, respectively, induce a potent tissue factor in ECs. The production of TF activity, TF antigen and TF mRNA is dose and time dependent. The TF activity was induced also by F(ab)2 but not by Fc fragments and was abolished completely by pre-incubation with ant-TF antibodies. The TF that is induced in ECs by AECAs with and without beta 2-GPI specificity may activate the coagulation and thereby play a major role in the pathogenesis of fibrin deposition and thrombus formation in diseases that are associated with the presence of these antibodies.

Do electromagnetic fields interact directly with DNA?

The mechanisms whereby electromagnetic (EM) fields stimulate changes in biosynthesis in cells are not known. It has has generally been assumed that EM fields first interact with cell membranes, but this pathway may not be only one. Interactions with membranes are well documented, but recent studies of EM signal transduction in the membrane Na,K-ATPase are best explained by direct interaction of electric and magnetic fields with mobile charges within the enzyme. Interaction with moving charges may be a mechanism that is operative in other biopolymers. Recent studies on DNA have shown that large electron flows are possible within the stacked base pairs of the double helix. Therefore, gene activation by magnetic fields could be due to direct interaction with moving electrons within DNA. Electric fields as well as magnetic fields stimulate transcription, and both fields could interact with DNA directly. The mechanism of EM field-stimulated transcription may be related to the process in striated muscles, where endogenous electrical activity induces the synthesis of new proteins.