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Biomedical subjects

O Abramsky

Publications and source records attributed to O Abramsky.

At least 37 records · Page 2Linked to original sources
PubMed1999

Elevated levels of antibody to myelin oligodendrocyte glycoprotein is not specific for patients with multiple sclerosis.

OBJECTIVE: To evaluate the presence and specificity of anti-myelin oligodendrocyte glycoprotein (MOG) antibody in the cerebrospinal fluid and plasma of patients with multiple sclerosis (MS). DESIGN: Case-control study of patients with clinically definite MS compared with patients with other neurologic diseases (ONDs) of the central nervous system and control subjects. SETTING: Referral center in the Department of Neurology of Hadassah University Hospital, greater Jerusalem area, Israel. PARTICIPANTS: Consecutive cerebrospinal fluid samples from 31 patients with MS, 31 patients with ONDs, and 28 healthy controls; and plasma samples from 33 patients with MS, 28 patients with ONDs, and 31 healthy controls were taken from the cerebrospinal fluid and plasma bank of the Department of Neurology, Hadassah University Hospital. MAIN OUTCOME MEASURES: Levels and frequencies of anti-MOG antibody in patients with MS, as defined by enzyme-linked immunosorbent assay. RESULTS: Cerebrospinal fluid levels of antibodies to MOG and to myelin basic protein were significantly higher in patients with MS (P<.001 and P = .001, respectively) and patients with ONDs (P = .005 and P = .03, respectively) compared with controls; frequency of antibodies to MOG, but not to myelin basic protein, was higher in patients with MS and patients with ONDs (P = .01 and P = .003, respectively, for the frequency of anti-MOG antibody, and P = .65 and P = .41, respectively, for the frequency of anti-myelin basic protein antibody). Plasma levels of antibodies to MOG and to myelin basic protein were higher in patients with MS compared with patients with ONDs (P = .003 for both comparisons) and with controls (P = .03 and P = .04, respectively); however, the frequency of antibodies to MOG and myelin basic protein was similar in patients with MS, patients with ONDs (P=.54 and P = .82, respectively), and controls (P = .50 and P = .14, respectively). CONCLUSIONS: The elevated presence of anti-MOG antibody is not specific for MS because a similar appearance was also demonstrated in patients with ONDs. Therefore, it is not clear whether this antibody is pathogenic in MS or, on the contrary, has a defensive role against further immune-mediated damage after myelin breakdown.

Adolescent↗
PubMed1999

HLA class II susceptibility to multiple sclerosis among Ashkenazi and non-Ashkenazi Jews.

OBJECTIVE: To look for HLA class II alleles and haplotypes conferring susceptibility to multiple sclerosis (MS) in the Jewish population of Israel. DESIGN: Population-based cohort of clinically definite patients with MS tested prospectively over 7 years. SETTING: Referral center in a neurology clinic at a university hospital in the greater Jerusalem area in Israel. PATIENTS: A total of 162 consecutive patients with clinically definite MS from the 2 main ethnic Jewish groups in Israel: 104 Ashkenazi (80 with a relapsing remitting or secondary progressive and 24 with a primary chronic progressive course of the disease) and 58 non-Ashkenazi (36 with a relapsing remitting or secondary progressive course and 22 with a primary chronic progressive course of the disease), matched with 132 Ashkenazi and 120 non-Ashkenazi healthy controls. MAIN OUTCOME MEASURES: The relationship between the various HLA class II alleles and haplotypes and MS, as defined by the polymerase chain reaction and sequence-specific oligonucleotide probe hybridization, among the Ashkenazi and the non-Ashkenazi Jewish sections and with respect to the different clinical courses of the disease. RESULTS: The haplotype DRB1*1501, DQA1*0102, DQB1*0602 was found to be associated with MS among both Ashkenazi and non-Ashkenazi patients (P<.001 and P =.04, respectively). Among the non-Ashkenazi patients, a new association of haplotypes DRB1*1303, DQA1*05, and DQB1*030 with MS was detected (P = .03). The MS susceptibility alleles, DRB 1* 1501, DQA1*0102, and DQB1*0602 , were found in association with the Ashkenazi patients (P<.001, P=.02, and P=.01, respectively); DRB1*1501 and DRB1*1303 were more frequently observed among the non-Ashkenazi patients (P = .03, P = .04, respectively). On subdivision of the patients into clinical subgroups, associations of DRB1*0801, DQA1*0102, DQA1*0401, and DQB1*0602 with primary chronic progressive MS among the Ashkenazi patients were evident (P = .03, P = .04, P = .04 and P = .05, respectively), whereas DRB1* 1501, DRB1*03011, and DQB1*0602 were associated with relapsing remitting or secondary progressive among the non-Ashkenazi patients (P = .05, P = .05, and P = .03, respectively). CONCLUSIONS: This study, unlike previous ones, is the first to show a significant association between HLA class II alleles and MS in the Jewish population. The association with the HLA-DR2-related haplotype is similar to that among non-Jewish white patients with MS. Moreover, our data support the possibility that DRB1*1501 is the susceptibility allele responsible for the association between this haplotype and MS in the Jewish population. Our study also underscores differences in HLA profiles between Ashkenazi and non-Ashkenazi patients, and between the different clinical courses of the disease. The latter may indicate that the clinical courses of MS are influenced by the genetic background.

Alleles↗
PubMed1999

Linomide induces apoptotic death of cortical CD4/CD8 double positive thymocytes and thymic atrophy by a corticosteroid-independent pathway.

Linomide is a synthetic immunomodulator which was shown to protect animals against a wide range of experimental autoimmune diseases. In this study we have investigated the effects of Linomide on the thymus in an effort to elucidate the mechanisms by which this immunomodulator suppresses autoimmune reactivity. Normal or adrenalectomized SJL/J mice were treated orally for 10 days with linomide (80 mg/kg/day). Thymocytes were tested by FACS for the analysis of the CD4 and CD8 markers and TCR expression on their surface. Thymuses from these animals were examined for size and cellularity and immunohistopathologically for the detection of apoptosis and for the expression of the markers CD4 and CD8. A significant reduction in the thymus size and cellularity was observed in mice treated with Linomide, starting from day 3 after treatment, accompanied by an enhanced apoptotic death of cortical thymocytes, which was first noted on day 1 of treatment and peaked on day 3. FACS analysis and immunohistochemistry revealed a significant depletion of the CD4(+)/CD8(+) (double positive) cells with a parallel relative increase of the more mature, medullar, single positive, lymphocytes. These effects on the thymus were not mediated through a corticosteroid-dependent pathway, and were also observed in adrenalectomized and Linomide-treated animals. These observations may be of importance for the clarification of the role of thymus in autoimmunity and the possible ways for immune intervention with immunomodulators like Linomide at this level.

Adjuvants, Immunologic↗
PubMed1999

Acute/relapsing experimental autoimmune encephalomyelitis: induction of long lasting, antigen-specific tolerance by syngeneic bone marrow transplantation.

Experimental autoimmune encephalomyelitis (EAE) is an inducible autoimmune disease widely used as a model of the acute/relapsing stage of multiple sclerosis. We have previously shown that treatment of EAE-mice with high doses of cyclophosphamide (CY) (350 mg kg), followed by syngeneic bone marrow transplantation (SBMT), completely abrogates the clinical paralytic signs and even prevents the appearance of new relapses in the chronic-relapsing model of the disease. In the present study we examined whether this treatment protocol induces long term tolerance and whether this tolerance is antigen-specific. EAE was induced by immunization with spinal cord homogenate (MSCH) in complete Freund's adjuvant (CFA). The treatment with CY and SBMT was performed on day 6 post immunization. Treated and untreated mice were rechallenged with MSCH, or a non-relevant antigen (OVA) in CFA at various stages after the first paralytic attack. In contrast to previous data showing that animals recovering from acute EAE are usually refractory to re-induction of the disease, repeated injections of MSCH at different sites from the initial immunization, followed by i.v. injection of inactivated Bordetella bacteria, 2, 4 and 6 months after the initial EAE-induction, caused a severe and usually lethal relapse in all the untreated, control animals. Mice treated with CY and SBMT were resistant to all rechallenges with the same encephalitogenic inoculum. Following the second rechallenge, peripheral lymph node cells were examined in vitro for their proliferative responses to myelin antigens or to OVA. Lymphocytes obtained from CY+SBMT treated mice did not proliferate in vitro in response to myelin basic protein (MBP), but proliferated against OVA, when immunized with this antigen, after SBMT. Adoptive transfer of lymphocytes from tolerant mice to naive recipients did not transfer resistance to EAE-induction. Our results indicate that high doses of CY, followed by SBMT, induce long term antigen-specific tolerance presumably by a mechanism of clonal deletion or anergy.

Animals↗
PubMed1999

Evidence for the genetic role of human leukocyte antigens in low frequency DRB1*1501 multiple sclerosis patients in Israel.

A strong association exists between multiple sclerosis (MS) and the DRB1*1501 haplotype, in most populations. Linkage of Multiple Sclerosis (MS) with the MHC or HLA region on chromosome 6p21 has previously been observed in DRB1*1501 positive MS families. A group of 13 Israeli multiplex MS families with a very low frequency of DRB1*1501 haplotype were examined in this study. Association and a linkage test were performed in order to identify a non-DRB1*1501 effect of HLA on susceptibility for MS. MS multiplex families and healthy controls were molecularly typed for six highly polymorphic markers located within the MHC region: DRB1, DQA1 and DQB1, BAT-2, MIB and D6S248. Data analyses included: (a) an association study comparing the patient group with both healthy relative, and healthy control groups (b) a transmission test for linkage disequilibrium (TDT) of the MS-associated alleles in the multiplex families, and (c) multipoint non-parametric linkage (NPL) and parametric LOD score analyses using the GENEHUNTER program. The DRB1*1303 allele was significantly more frequent among the MS patients. There was a trend towards transmission disequilibrium of DRB1*1303, but was not statistically significant. Allele sharing and LOD score analyses revealed no evidence for linkage. The high frequency of DRB1*1303 observed in our family patients provides evidence to support the association with this allele that previously described in sporadic non-Ashkenazi MS patients. Thus, DRB1*1303 may serve as genetic risk factor for MS. Our study exemplifies the genetic heterogeneity in MS as there is a genetic effect of HLA on MS susceptibility in our low frequency DRB1*1501 patients.

Alleles↗
PubMed1998

Immunomodulating therapeutic approaches for multiple sclerosis.

In this review we delineate the rationale for immunotherapy in multiple sclerosis and describe the various levels at which immune intervention, according to a modern model of the immune system organization, is feasible. Current and future immunosuppressive and immunomodulating therapeutic approaches at the level of antigen presentation and at the lymphocyte and cytokine network levels are discussed.

Adjuvants, Immunologic↗
PubMed1998

A subgroup of multiple sclerosis patients with anticardiolipin antibodies and unusual clinical manifestations: do they represent a new nosological entity?

The presence of antibodies to cardiolipin (ACL Abs) has been reported in some patients suffering from multiple sclerosis (MS), especially of the "neuromyelitic" type. In addition, bright T2-imaging foci (unidentified bright objects) are occasionally detected on brain magnetic resonance imaging (MRI) scans, in patients with antiphospholipid syndrome. From a cohort of 100 patients with a probable or definite diagnosis of MS according to Poser's criteria, we isolated a subgroup of 20 patients (8 males and 12 females) consistently positive for ACL Abs. These patients were followed up neurologically for 1 to 3 years and brain MRI scanning and a complete autoimmune screening were performed. Nineteen (19 of 20) of our patients had the classic neuroimaging features of MS (multiple white-matter T2 bright foci on the MRI scan). The most common neurological syndrome was chronic, slowly progressing myelopathy (presenting as myelopathy, neuromyelitis optica, or spinocerebellar syndrome; 15 of 20), and optic neuropathy (6 of 20). Headache was a dominant symptom in 8 of 20 patients. Less common symptoms included cognitive and psychiatric disorders and chronic fatigue. The mean levels of ACL Abs were 38.8+/-28.2 GPL (normal values up to 7.5). Oligoclonal bands in the cerebrospinal fluid were detected in only 3 of 20 patients. Patients were treated with acetylsalycilic acid and occasionally with short courses of steroids. The progression of the chronic myelopathic/spinocerebellar syndrome was slower than expected in MS (only 2 patients deteriorated whereas 4 improved during a mean follow-up period of 20.8+/-7.1 months). We conclude that patients with probable or definite diagnosis of MS, and consistently elevated levels of ACL Abs show a slower progression and some atypical (for MS) features, such as persistent headaches and absence of oligoclonal bands in the cerebrospinal fluid. In these patients, other, presumably vascular, mechanisms may be involved in the pathogenesis of the neurological symptoms. Therefore, management should include antiplatelet or even anticoagulant agents.

Adult↗
PubMed1998

Adult polyglucosan body disease in Ashkenazi Jewish patients carrying the Tyr329Ser mutation in the glycogen-branching enzyme gene.

Adult polyglucosan body disease (APBD) is a late-onset, slowly progressive disorder of the nervous system caused by glycogen branching enzyme (GBE) deficiency in a subgroup of patients of Ashkenazi Jewish origin. Similar biochemical finding is shared by glycogen storage disease type IV (GSD IV) that, in contrast to APBD, is an early childhood disorder with primarily systemic manifestations. Recently, the GBE cDNA was cloned and several mutations were characterized in different clinical forms of GSD IV. To examine whether mutations in the GBE gene account for APBD, we studied 7 patients from five Jewish families of Ashkenazi ancestry. The diagnosis was based on the typical clinical and pathological findings, and supported by reduced GBE activity. We found that the clinical and biochemical APBD phenotype in all five families cosegregated with the Tyr329Ser mutation, not detected in 140 controls. As this mutation was previously identified in a nonprogressive form of GSD IV and was shown in expression studies to result in a significant residual GBE activity, present findings explain the late onset and slowly progressive course of APBD in our patients. We conclude that APBD represents an allelic variant of GSD IV, but the reason for the difference in primary tissue involvement must be established.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1998

Exacerbation of myasthenia gravis during the menstrual period.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disorder mediated by antiacetylcholine receptor antibodies. It has long been suspected to exacerbate during the menstrual period but this has never been adequately documented. SUBJECTS AND METHODS: We questioned 120 female myasthenic patients of different ages, about their myasthenic symptoms before and during the menstrual period. We also evaluated the effect of medications, pain and stress during or before the menstrual period on the exacerbation rate. Exclusion criteria were postmenopausal age and incomplete information available in the questionnaire. RESULTS: Forty two premenopausal women with generalized disease were included in the study. Twenty eight (67%) of the patients reported exacerbation of their myasthenic symptoms 2 to 3 days prior to the menstrual period. This exacerbation persisted in 22 of them to the third day of the menstrual period. In nine of the women this clinical worsening necessitated an increased intake of medications during the days prior to menstruation. No correlation could be found between the presence of antiacetylcholine receptor antibodies, pain, stress, use of oral contraceptives or the type of antimyasthenic therapy and the rate of exacerbation before and during the menstrual period. CONCLUSIONS: (1) MG frequently exacerbates before and during the menstrual period in 67% of MG patients. (2) The rate of exacerbation is unrelated to the presence of stress or pain prior to or during the menstrual period. (3) Different therapies directed against MG, as well as oral contraceptives do not influence the clinical course. (4) Menstrual exacerbations occur in both seronegative and seropositive patients. (5) These exacerbations may frequently necessitate therapeutic changes.

Adult↗
PubMed1998

Inhibition of experimental autoimmune neuritis by the immunomodulator linomide.

Experimental autoimmune neuritis (EAN) is an animal model that shares clinical, pathological and electrophysiological features with the human disease Guillain-Barre syndrome. The synthetic immunomodulatory substance linomide has been successfully used to prevent the development of several experimental autoimmune models in laboratory animals and has been proved to be beneficial in modulating the course of multiple sclerosis in humans. In the present study we demonstrate that oral administration of linomide prevents the development of clinical and histopathological signs of EAN in Lewis rats, inoculated with the P2 (60-70) synthetic peptide. The immunomodulatory effect of linomide on this experimental model of disease was associated with marked apoptosis of lymphocytes in thymus and spleen early after starting the treatment. Furthermore, a downregulation of the endothelial expression of the adhesion molecules ICAM-1 at the target site and LFA-1 on lymphocytes could also contribute to the absence of inflammatory cells in the neuraxis.

Adjuvants, Immunologic↗
PubMed1998

Early anticoagulation in patients with prosthetic heart valves and intracerebral hematoma.

Anticoagulants are generally contraindicated in patients with intracerebral hematoma. However, in patients with prosthetic heart valves it may be dangerous to withhold such therapy because of possible thromboembolic complications. We treated four such patients with i.v. heparin starting early after the hemorrhage. The hematomas receded in all patients according to the follow-up CTs, and none had thromboembolic disorders. Three patients had good outcomes, and one remained in a persistent vegetative state after an event of acute pulmonary edema.

Adult↗
PubMed1997

Adult-onset Niemann-Pick type C disease. Clinical, biochemical, and genetic study.

BACKGROUND: Niemann-Pick type C disease is an autosomal recessive neurometabolic disorder of unknown origin mapped to chromosome 18q11-12 in most of the studied families. In contrast to the sphingomyelin lipidoses, in Niemann-Pick type C disease, fibroblasts are impaired in intracellular homeostatic responses to exogenous low-density lipoprotein (LDL) cholesterol. Biochemical heterogeneity of the disorder in relation to abnormal LDL processing is associated with various clinical presentations, but adult-onset Niemann-Pick type C disease is rare and has not been comprehensively characterized. OBJECTIVE: To describe clinical, biochemical, and genetic features of adult-onset Niemann-Pick type C disease in 3 siblings. DESIGN AND SETTING: Case series in a tertiary care center. PATIENTS: The 3 siblings manifested a variable combination of vertical supranuclear ophthalmoplegia, ataxia, and splenomegaly. Brain magnetic resonance imaging showed cerebellar atrophy; brainstem auditory evoked responses were unobtainable, and bone marrow examination disclosed typical foam cells. The patients were 20, 26, and 28 years old and belonged to a sibship of 13 born of consanguineous healthy parents. METHODS: Esterification of exogenous LDL cholesterol in cultured skin fibroblasts and filipin staining for free intracellular cholesterol. Polymerase chain reaction-based DNA linkage study using AC microsatellite markers D18S40, D18S44, D18S480, and D18S66. RESULTS: Fibroblasts of the 3 patients showed a 23% to 58% block in the induced cholesterol esterification after 4 1/2 hours and a mild to moderate accumulation of free cholesterol. DNA study demonstrated linkage to the major 18q11-12 Niemann-Pick type C locus and identified unaffected carriers. CONCLUSIONS: These results confirm the diagnosis of the least biochemically affected Niemann-Pick type C phenotype in this family with adult-onset disease and support a correlation between the mild laboratory and clinical findings in this age group.

Adult↗
PubMed1997

Predominance of the autoimmune response to myelin oligodendrocyte glycoprotein (MOG) in multiple sclerosis: reactivity to the extracellular domain of MOG is directed against three main regions.

Our previous analysis of the T cell reactivity to myelin antigens in a group of 24 patients with multiple sclerosis (MS) and 16 control individuals revealed that the autoimmune response to myelin oligodendrocyte glycoprotein (MOG) predominates in MS over that to myelin basic protein (MBP), proteolipid protein or myelin-associated glycoprotein, suggesting a prevalent role for the autoimmune response to MOG in the pathogenesis of MS. Using a recombinant human MOG (rhMOG) preparation corresponding to the extracellular immunoglobulin-like domain of the MOG molecule, we have now analyzed another group of 52 MS patients and 49 control individuals for reactivity of their peripheral blood lymphocytes (PBL) to rhMOG and to MBP concomitantly. Of the 52 MS patients tested 24 responded to MOG and 10 out of 49 responded to MBP, whereas only 5 MOG-reactive and 4 MBP-reactive control individuals were detected out of the 49 tested. These results are therefore highly confirmatory of the predominant reactivity to MOG in MS. The analysis of the primary proliferative response to 11 synthetic overlapping peptides (phMOG) spanning the extracellular domain of human MOG by PBL from 9 MS patients and 15 control individuals (9 healthy controls and 6 patients with neurological diseases other than MS) further supports a prevalent role for the autoimmune response to MOG in MS, as only 1 of the 15 controls tested showed reactivity to any of the phMOG, whilst 5 out of the 9 patients studied reacted to at least 1 of the phMOG. PBL from 10 MS patients, and from 4 controls, were selected in vitro with each of the phMOG. Of the 10 patients studied 7 reacted to at least 1 phMOG upon secondary stimulation and the reactivity was mostly directed to epitopes localized within three main regions (amino acids 1-22, 34-56 and 64-96), as was observed for the primary response of PBL. The predominant response to MOG of PBL from MS patients as demonstrated in two separate studies using native MOG and rhMOG as antigens, and the high incidence of reactivity of these PBL compared to the lack of response to phMOG by control PBL, emphasize the relevance of MOG in MS pathogenesis and support a primary role for the autoimmune T cell response to MOG in disease development.

Adult↗
PubMed1997

Inhibition of the progression of multiple sclerosis by linomide is associated with upregulation of CD4+/CD45RA+ cells and downregulation of CD4+/CD45RO+ cells.

In a recent double-blind, phase II study, conducted in our department, we showed that Linomide-treated MS patients had significantly less active lesions (in serial monthly MRI tests) and a tendency for clinical stabilization. Here we present the immunological evaluation of the patients who participated in this study and propose a novel mechanism by which Linomide downregulates autoreactivity. Peripheral blood leukocytes (PBLs), serum, and CSF samples were obtained at two to four time points over the 6 months of the trial. Flow cytometric analysis (FACS) of the CD5/CD19, CD4/CD8, CD14/CD3, CD16/CD3, CD45RA/CD4, and CD45RO/CD4 surface markers on PBLs was performed and the levels of the IL-1beta, IL-2, IL-4, IL-6, IL-10, TNF-alpha, IFN-gamma, and IL-2R were also examined. White blood counts of Linomide-treated patients were consistently elevated throughout the treatment period (P = 0.002-0.04). Cytokines levels in serum and CSF were highly fluctuating and we could not detect any clear trend as a result of Linomide treatment. FACS analysis showed that Linomide treatment significantly increased the percentage of the CD4+/CD45RA+ cells (from 35.5% at baseline to 42.3% at week 24; P = 0.02), and decreased CD4+/CD45RO+ lymphocytes (62.6% at baseline vs 53.7% at week 24, P = 0.02). Linomide also induced a transient increase in the NK-cells, the NK 1.1 cells, and the CD5 B-cells (P = 0.02). Upregulation of naive CD45RA T-lymphocytes and parallel downregulation of memory CD45RO cells seems to be one of the main mechanisms by which Linomide inhibits MS activity and may represent an alternative immunomodulating approach for the treatment of MS and autoimmunity in general.

Adjuvants, Immunologic↗
PubMed1997

Immunomodulation of autoimmunity by linomide: inhibition of antigen presentation through down regulation of macrophage activity in the model of experimental autoimmune encephalomyelitis.

Linomide (quinoline-3-carboxamide, LS-2616), a synthetic immunomodulator, protects animals against a variety of experimental autoimmune diseases. In experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), linomide blocks both the clinical and histological signs of the disease, without inducing generalized immunosuppression. In the first clinical trial in patients with MS, linomide was shown to inhibit the progression of the disease. In the present study we investigated several aspects of the mechanisms of action of this immunomodulator. We found that linomide can inhibit acute EAE even when given as pretreatment, prior to induction of disease (days - 10 to 0). This inhibitory effect was reversed by adoptive transfer of naive spleen cells. A short course (7 days) of linomide treatment also inhibited EAE, especially when administered immediately after disease induction. Spleen cells from linomide-treated mice failed to present myelin antigens to T-cell lines in vitro. The defective antigen presentation was normalized by anti-oxidants such as 2-mercaptoethanol. The proportion of Mac1+ cells in the spleens of linomide-treated mice was significantly reduced and macrophage growth was inhibited in long term cultures of spleen cells derived from linomide-treated animals. Our findings suggest that the effect of linomide on EAE may be attributed, at least in part, to inactivation of antigen presenting cells, possibly following a short period of over-stimulation and increased oxidant production. This mechanism may play a universal role in the regulation of autoimmune reactivity and merits further investigation.

Adjuvants, Immunologic↗