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Biomedical subjects

Y Levy

Publications and source records attributed to Y Levy.

At least 163 records · Page 9Linked to original sources
PubMed1998

Thromboembolic phenomena in patients with hereditary factor XI deficiency.

Factor XI deficiency is an hereditary coagulopathy that is usually associated with milder tendency to bleeding with comparison to hemophilia A. While the failure of stable fibrin clot formation may lead to bleeding, it is speculated that the same process may provide a protection against thrombosis of injured arteries due to atherosclerotic plaque rupture. Whereas 2 studies indicate that hemophiliacs have decreased mortality rate from cardiovascular diseases, there is no similar data regarding factor XI deficiency patients. In here we report about 3 patients with severe factor XI deficiency who have a long-standing history of thromboembolic phenomena: 2 patients with myocardial infarctions, and one patient with transient ischemic attacks. We discuss the possible role of factor XI in thrombosis, and whether its deficiency may protect patients from thromboembolic phenomena.

Adult↗
PubMed1998

The pathogenic 16/6 idiotype in patients with silica associated systemic lupus erythematosus (SLE) and uranium miners with increased risk for development of SLE.

OBJECTIVE: To investigate the prevalence of the 16/6 idiotype (16/6 Id), a major cross reactive idiotype of anti-DNA antibodies involved in the pathogenesis of experimental lupus, in subjects with an exogenous risk for the development of systemic lupus erythematosus (SLE). METHODS: The titer of 16/6 Id was determined by ELISA in sera of uranium miners exposed to heavy quartz dust: 15 developed definite and 12 probable SLE, 34 had clinical symptoms, and 27 had only serological signs (medium to high titer anti-dsDNA antibodies) of possible connective tissue disease (CTD) development. RESULTS: The prevalence of 16/6 Id was higher in all groups compared to healthy blood donors. It was 18.5% in miners with SLE (definite and probable) and 22.2-26.5% in miners with clinical and/or serological signs for developing CTD. All 16/6 Id positive miners were positive for anti-dsDNA antibodies and other autoantibodies associated with CTD. The prevalence of 16/6 Id in anti-dsDNA positive miners correlated slightly with CTD/SLE symptoms: 55.6% in patients with SLE, 47.4% in miners with possible CTD/SLE, and 22.2% in miners without CTD symptoms. Further, at short term followup, disease progressed in 2 miners of the 16/6 Id positive, but not in 16/6 Id negative miners. CONCLUSION: The detection of 16/6 Id in miners exposed to quartz dust may indicate a higher risk for development of SLE, warranting further studies of the role of 16/6 Id in the development of SLE in a cohort with the same sex, ethnicity, geographic region, and occupation.

Aged↗
PubMed1997

Neurological dysfunction and hyperactive behavior associated with antiphospholipid antibodies. A mouse model.

Antiphospholipid antibodies (aPL) have been associated with various neurological manifestations, but the underlying mechanism has not been elucidated. We assessed mice with induced experimental antiphospholipid syndrome (APS) for neurological and behavioral changes. After immunization with monoclonal human anticardiolipin antibody (H-3), female BALB/c mice developed elevated levels of circulating anti-negatively charged phospholipids (aPL), anti-beta2-glycoprotein I (abeta2GPI), and anti-endothelial cell antibodies (AECA), along with clinical manifestations of APS like thrombocytopenia and fetus resorption. APS mice were impaired neurologically and performed several reflexes less accurately compared to the controls, including placing reflex (P < 0.05), postural reflex (P < 0.05), and grip test (P = 0.05). The APS mice also exhibited hyperactive behavior in an open field, which tests spatial behavior (P < 0.03), and displayed impaired motor coordination on a rotating bar. aPL in combination with abeta2GPI and AECA is probably involved in the neurological and behavioral defects shown in mice with experimental APS.

Animals↗
PubMed1997

Subcutaneous T-cell lymphoma in a patient with rheumatoid arthritis not treated with cytotoxic agents.

This case report describes an 81-year-old patient with prolonged rheumatoid arthritis (RA), which was complicated by the occurrence of a subcutaneous T-cell lymphoma. During the course of his illness the patient had not been treated with disease-modifying agents (i.e. cytotoxic agents), but only symptomatically with anti-inflammatory drugs. This finding demonstrates a previously undescribed association between RA and a rare from of subcutaneous T-cell lymphoma, which may add more information to the controversial issue of emergence of malignancy in RA.

Aged↗
PubMed1997

Refractory intraocular pressure increase after photorefractive keratectomy.

A patient with developmental angle anomaly developed a corticosteroid-induced refractory increase in intraocular pressure (IOP) after photorefractive keratectomy (PRK). Trabeculectomy was required to reduce the pressure. Although rare, corticosteroid-induced refractory IOP increase is a serious complication of PRK and may necessitate trabeculectomy. More frequent monitoring of IOP in post-PRK patients and a re-evaluation of postoperative treatment are indicated.

Adult↗
PubMed1997

Autonomous linguistic systems in the language of young children.

This paper considers cross-linguistic findings concerning the early development of formal, arbitrary, grammatical systems in normal hearing and deaf children and in children with congenital brain abnormalities. The paper reviews evidence showing an early acquisition of grammatical forms. Such learning is typically dissociated from the development of the relevant semantics. Form-function correspondences were not required for the development of morphological paradigms and for certain aspects of formal syntax. This finding held across all the populations studied. It is hypothesized that the autonomous nature of these formal paradigms accounts for their priority in learning cross-linguistically.

Child↗
PubMed1997

Smoking and immunity: an additional player in the mosaic of autoimmunity.

Autoimmune diseases are associated with a variety of predisposing factors. However, the relative contribution of each remains to be established. The purpose of the paper is to focus on cigarette smoking, a common Western habit, as a possible environmental factor for the emergence of autoimmunity. This association is described in view of several recent studies documenting increased susceptibility to autoimmune diseases among smokers.

Animals↗
PubMed1997

Infections and Wegener's granulomatosis--a cause and effect relationship?

The association of infections and autoimmune disease has been noted by various authors. Several mechanisms have been proposed to explain this, with no current consensus. Wegener's granulomatosis (WG) is an autoimmune disease involving predominantly the pulmonary and renal systems, and is associated with a distinct autoantibody-the anti neutrophil cytoplasmic antibody (ANCA). Although no solid evidence implicates infections in the emergence of WG, direct and circumstantial data suggest this relation. We review this evidence and discuss possible underlying mechanisms. We emphasize the relationship between infections and ANCA, and their role in the maintenance of the 'on-going' inflammatory response.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1997

IL-7 sensitizes human pre-B cells but not pro-B cells to Fas/APO-1 (CD95)-mediated apoptosis.

Homeostasis of human B cell development is maintained by a complex network of cytoplasmic and surface expressed molecules. Abnormalities in this process may result in the expansion of malignant B cell precursors in B lineage acute lymphoblastic leukaemia (ALL). ALL cells share surface antigens with normal early precursor B cells. We have studied here the role of Fas/APO-1 (CD95) antigen on leukaemic precursor B cell line growth and survival, and the modulation of its effects by signals involved in normal early B cell development. Four ALL cell lines representative of the early steps of B cell differentiation are shown to express surface Fas/APO-1 (CD95) antigen and to undergo apoptosis in the presence of anti-Fas cross-linking antibodies. This effect is strongly enhanced when pre-B, but not pro-B cells, are pretreated with IL-7 but not with IL-2, IL-3, IL-4 or IL-10. Furthermore, pre-B cell death induced by anti-Fas antibodies in combination with IL-7 is increased upon pre-B receptor but not CD19 cross-linking. Bcl-2 and Bax protein expression is not influenced by IL-7 or pre-BR stimulation in either pro-B or pre-B cell lines. These results indicate that signals involved in normal early B cell development can modulate the Fas (CD95)-mediated apoptosis of leukaemic precursor B cells.

Apoptosis↗
PubMed1997

'Autoantibody dominance' pattern following idiotypic manipulation of naive mice by immunization with anti-U1RNP antibodies.

OBJECTIVE: To study the immune response and clinical findings in mice immunized with different epitope-specific anti-U1RNP antibodies purified from the sera of mixed connective tissue disease (MCTD) patients with various clinical manifestations. METHODS: BALB/c mice were immunized with anti-U1RNP-IgG preparations from 3 patients with MCTD. Group 1 was immunized with U1 70 kD A-positive IgG, group 2 with U1 70 kD-negative, U1A, U1C, B-B'-positive IgG and group 3 with U1 70 kD, U1A, U1C-positive IgG. The induced autoantibody response in the mice was studied by ELISA and immunoblots and the clinical findings of MCTD in humans were assessed. RESULTS: Immunoblot assays showed that mice immunized with different human anti-U1RNP antibodies developed predominantly autoantibodies directed against U1 68-70 kD epitope. This 'autoantibody dominance' pattern was not associated with clinical findings. CONCLUSIONS: The restricted murine autoimmune response may provide clues to the diversified autoantibody production in autoimmune diseases and explain in part the changing patterns of clinical findings in individuals with MCTD.

Animals↗
PubMed1997

Successful treatment of early secondary myelofibrosis in SLE with IVIG.

Myelofibrosis has been reported as a rare cause of pancytopenia in patients with autoimmune diseases. We describe a 54y old female patient who was admitted with severe anemia subsequently found to be due to marrow fibrosis. During the course of her hospitalization, relying both on her clinical symptoms as well as the results of a wide range of laboratory tests and diagnostic procedures, the diagnosis of systemic lupus erythematosus was established. The patient was treated with high dose steroids, but improvement of her clinical symptoms as well as normalization of her peripheral blood count were achieved only after high dose intravenous therapy with gamma globulin (IVIG) was instituted. Along with the improvement in the peripheral blood parameters normalization of the bone marrow architecture was recorded on a repeated bone marrow biopsy. IVIG therapy should be considered in extreme cases of bone marrow suppression in SLE.

Biopsy↗
PubMed1997

The development of morphology and syntax in a pair of DZ twin boys.

Twins provide a natural set-up for the study of some of the basic issues that concern the field of language acquisition and of developmental language disorders and brain pathology, in that they present a unique hereditary and environmental situation within which development takes place. Yet, few studies have detailed the development of formal aspects of language in twins. This paper reports on a prospective, longitudinal study of the acquisition of selected aspects of Hebrew syntax and morphology in a pair of DZ twin boys, aged 3;6-4;0, one of whom had a congenital brain abnormality. MLU levels suggest a marked delay for both children in the onset and progression of language development. However, both the healthy and the brain-injured twin followed a normal developmental course. Data to that effect concern frequency of sentences of various lengths, distribution of sentence types, use of tenses, use of pronouns, correct usage of various syntactic markers, variability of verb types and tokens and the distribution of errors of morphology and morphophonology. It is argued that this case study offers support for claims concerning brain plasticity for language. Furthermore, it is in line with previous studies of normal and brain-injured children which, rather unexpectedly, pointed at the relative ease with which formal, linguistic systems were acquired.

Cerebral Ventricles↗
PubMed1997

Evaluation of mid-term stability of night vision tests.

BACKGROUND: Dark adaptation rate, scotopic retinal sensitivity and contrast sensitivity under mesopic conditions, but not visual acuity, have been shown to be directly related to the ability to identify military targets at night. These parameters can be used to select personnel for specific military tasks demanding excellent night vision, as well as to assess pharmacological effects on night vision. PURPOSE: To evaluate the mid-term (2 to 6-week period) stability of night vision tests based on assessment of the above parameters. METHODS: Dark adaptation rate, scotopic retinal sensitivity and contrast sensitivity under mesopic conditions were studied in 16 young volunteers during a 6-week period. RESULTS: Tests of scotopic retinal sensitivity (after 30 min of dark adaptation) exhibited high reproducibility and a low fluctuation rate, with a high correlation between values at week 0 and at 2-week intervals during the following 6 weeks of the study (rs (week 0 to week 6) = 0.81, p = 0.0001). The reproducibility of mesopic contrast sensitivity tests (average of 1.5, 3, 6 and 12 cycles per degree, (cpd)) was fair (rs (week 0 to week 2) = 0.67, p = 0.0045), whereas that of dark adaptation rate tests was poor. CONCLUSIONS: In view of the reproducibility characteristics of these night vision tests, assessment of night vision ability in pilots and military personnel, as well as assessment of pharmacological effects on night vision, may be based on scotopic retinal sensitivity (after 30 min of dark adaptation) and contrast sensitivity under mesopic conditions (average of 1.5, 3, 6 and 12 cpd).

Adult↗