Zipora Kra-Oz

Technion - Israel Institute of Technology, H̱efa, Haifa, Israel

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Publications (4)15.85 Total impact

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    ABSTRACT: Therapeutic options for progressive multifocal leukoencephalopathy (PML) caused by reactivation of John Cunningham virus (JCV) are limited and inefficient in preventing neurological progression and death. The current study investigated the course of JCV reactivation resulting in PML in patients undergoing allogeneic stem cell transplantation (allo-SCT) and assessed the feasibility and potential significance of preemptive JCV detection in peripheral blood, enabling early cessation of immunosuppressive therapy and immune restoration. Two allografted patients were diagnosed with PML at 188 and 808 days post-allo-SCT. Stored DNA samples of both patients, originally obtained for quantitative cytomegalovirus PCR analysis since transplantation, were evaluated for JCV. JCV reactivation in peripheral blood was found to precede the appearance of neurological symptoms by 126 and 105 days. JCV blood levels were found to be highly correlated with the steroid dosage administered for treating graft-versus-host disease (GVHD). In one patient, the cessation of immunosuppression, including steroids, led to the disappearance of JCV in peripheral blood, with a remarkable improvement in neurological symptoms. In conclusion, the current study suggests the feasibility of early detection of JCV reactivation in blood. Immune restoration at that point may prevent PML development; however prospective studies are warranted to elucidate these issues.
    Full-text · Article · Jul 2014 · International Journal of Infectious Diseases
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    ABSTRACT: Preemptive ganciclovir therapy has reduced the occurrence of early cytomegalovirus (CMV) disease after hematopoietic stem cell (HSC) transplantation. However, late disease is increasingly reported. We describe 2 patients who developed late CMV central nervous system (CNS) disease after haploidentical HSC transplantation. Direct genotypic analysis was used to examine the presence of ganciclovir resistance. One patient had a mixed viral population in the cerebrospinal fluid (CSF), with coexistent wild-type and mutant UL97 sequences. The presence of 2 different strains was confirmed by subclone sequencing of the UL54 gene. One of the strains was different from the concurrent blood strain. The second patient had resistant variant in the lungs. These cases raise concern about the changing natural history of CMV disease in HSC transplantation, with emergence of previously uncommon manifestations following prolonged prophylaxis. Under these circumstances the CNS may be a sanctuary site, where viral persistence and antiviral drug resistance could result from limited drug penetration.
    Full-text · Article · Feb 2003 · Blood
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    ABSTRACT: Primary human cells enter senescence after a characteristic number of population doublings (PDs). In the current study, human skin fibroblasts were propagated in culture under 5.5mM glucose (normoglycemia); addition of 16.5mM D-glucose to a concentration of 22 mM (hyperglycemia); and addition of 16.5mM L-glucose (osmotic control). Hyperglycemia induced premature replicative senescence after 44.42+/-1.5 PDs compared to 57.9+/-3.83 PDs under normoglycemia (p<0.0001). L-Glucose had no effect, suggesting that the effect of hyperglycemia was not attributed to hyperosmolarity. Activated caspase-3 measurement showed a significantly higher percentage of apoptotic cells in high glucose medium. Telomerase overexpression circumvented the effects of hyperglycemia on replicative capacity and apoptosis. The "point of no return," beyond which hyperglycemia resulted in irreversible progression to premature replicative senescence, occurred after exposure to hyperglycemia for as few as 20 PDs. These results may provide a biochemical basis for the relationship between hyperglycemia and those complications of diabetes, which are reminiscent of accelerated senescence.
    Full-text · Article · Aug 2002 · Biochemical and Biophysical Research Communications
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    ABSTRACT: Background: Of the donor corneas rejected for transplantation, the largest group is that from donors testing seropositive for hepatitis C virus (HCV). In situations of severe shortage in supply of donor corneal tissue, we may consider the use of seropositive donors for transplantation if we can prove with high certainty the absence of HCV RNA in the donor corneal tissue. Polymerase chain reaction (PCR) is a highly sensitive and specific technique for direct detection of HCV RNA and can be used for this purpose. Nevertheless, it is not applicable for routine clinical use in most eye departments due to its unavailability and cost effectiveness. Purpose: To study the possible use of immunohistochemical method for detection of HCV antigen in corneal tissue of seropositive donors and correlate the results with those of PCR. Immunohistochemical methods have not yet been studied in donor corneal tissue. Materials and methods: Eight corneas of 4 seropositive and 8 corneas of 4 seronegative corneal donors were studied by immunohistochemical and PCR methods for the presence of HCV antigen in their corneal tissue and sera. Results: HCV RNA was not detected in the sera and corneal tissue of all seropositive and seronegative corneal donors by either PCR and immunohistochemical methods. Conclusion: Although the study is too small for conclusive results, the correlation between the immunohistochemical and PCR studies for direct detection of HCV antigen in corneal tissue of seropositive donors may raise the possibility of using the immunohistochemical method for screening of donor corneas for the detection of HCV antigen. A larger prospective study investigating the sensitivity, specificity and clinical applicability of the immunohistochemical method is warranted.
    No preview · Article · Feb 2002 · Cell and Tissue Banking