Search PubMed⌕ Search

Biomedical subjects

Y Naparstek

Publications and source records attributed to Y Naparstek.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Immunospecific inhibition of nerve conduction by T lymphocytes reactive to basic protein of myelin.

Experimental autoimmune encephalomyelitis (EAE) induced by immunization to the basic protein of central nervous system myelin (BP) is a paralytic disease in which T lymphocytes attack the individual's own central nervous system. As the target is in white matter, EAE has been considered an experimental model of some aspects of human disease such as multiple sclerosis. To investigate whether autoimmune T lymphocytes could produce paralysis, we studied the effects on the electrophysiology of isolated nerves produced by T-lymphocyte lines reactive specifically to BP or other antigens. We now report that propagation of action potentials evoked by electrical stimulation was blocked by incubating optic nerves with specific anti-BP T cells. This blockade could be reversed for up to two hours by removing the anti-BP line cells from the optic nerve. The anti-BP line cells had no effect on conduction along allogeneic optic nerves or syngeneic peripheral nerves. This indicates that disruption of the function of myelin in neuroimmunological disease may result from an immunologically specific interaction between autoimmune T lymphocytes and myelin antigens.

Action Potentials↗
PubMedDate not supplied

Activated T lymphocytes produce a matrix-degrading heparan sulphate endoglycosidase.

We have previously found that lines of activated T lymphocytes specifically autosensitized to the basic protein of myelin (BP), on intravenous inoculation into syngeneic rats, were able to penetrate blood vessels, accumulate in the nervous system and cause experimental autoimmune encephalomyelitis (EAE). An important question is how effector T cells reach such targets outside the walls of blood vessels. To investigate this we have studied in vitro the interaction of anti-BP effector T lymphocytes with the basement membrane-like extracellular matrix produced by vascular endothelial cells. We now report that activated but not resting T lymphocytes produce an endoglycosidase capable of degrading heparan sulphate side chains of the proteoglycan scaffold of the extracellular matrix. Moreover, the anti-BP T lymphocytes respond to BP presented by extracellular matrix by markedly enhanced elaboration of the endoglycosidase. These results suggest that tissue-specific antigens on blood vessel walls could direct lymphocyte homing by activating enzymes that facilitate penetration of the subendothelial basal lamina. They also suggest that effector T lymphocytes can recognize antigen which is not associated with a major histocompatibility complex signal.

Animals↗
PubMedDate not supplied

The future of the treatment of systemic lupus erythematosus.

Despite recent advances, patients with systemic lupus erythematosus (SLE) still experience considerable morbidity and mortality. To try and improve their prognosis, varied novel biological interventions and immune manipulations are being developed. They may hold promise in particular for patients whose disease is organ-threatening and refractory to conventional treatment. In addition, awareness of the tendency of lupus patients to develop accelerated atherosclerosis as well as newly gained insights into the underlying mechanisms, may lead to better control of risk factors, earlier diagnosis of prevalent cardiovascular disease and more effective treatment. Infections also remain a significant threat that may be amenable to improved preventive measures. Evidence related to a better management of lupus patients by specialists, the need to address the impact of commonly associated stress and depression and other significant developments are also presented and discussed.

Animals↗
PubMedDate not supplied

Alveolar hemorrhage in cryoglobulinemia--an indicator of poor prognosis.

OBJECTIVE: Alveolar vasculitis is an unusual event in the course of cryoglobulinemia (CG). The inflammatory process involving the alveolar capillary walls may result in severe alveolar hemorrhage and consequently lead to a grave outcome. The objective of this study was to evaluate the occurrence of this unusual finding in CG. METHODS: We reviewed the records of all patients with CG who developed acute alveolitis, registered their associated clinical and laboratory parameters and evaluated the possible impact these parameters may have on their prognosis. In addition we scanned the Medline for similar cases. RESULTS: Of the 125 patients with CG who were hospitalized in our medical center during the last 23 years, 4 (3.2%) developed alveolar hemorrhage. All patients exhibited extreme fatigue, fever with clinical and radiological evidence of alveolitis. Of the 4 new cases, 1 had type II CG and 3 had type III CG. Of our 4 patients, 3 developed concomitant acute renal failure necessitating hemodialysis. A literature survey resulted in 6 additional cases. All 10 patients experienced acute respiratory insufficiency and eight had at least one episode of hemoptysis. In the other 2 patients the bronchoalveolar lavage (BAL) fluid contained hemosiderin laden macrophages. Five of the 10 patients had concomitant hepatitis C virus (HCV) infection; 2 patients were seen prior to modern identification of the HCV; however, liver abnormalities were not described. Of the 10 patients 5 patients had type II CG and 5 others had type III. Of the 7 patients in whom outcome was available, 6 died from their illness. Acute renal failure or exacerbation of antecedent glomerular disease occurred in 8 patients. CONCLUSIONS: Alveolitis is a rare manifestation of CG, presenting as an overwhelming systemic illness and portends a poor prognosis with a high mortality rate.

Adult↗