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M Margalith

Publications and source records attributed to M Margalith.

At least 19 recordsLinked to original sources
PubMed2005

Detection of HCV salivary antibodies by a simple and rapid test.

Hepatitis C (HCV) is common in developing countries, where blood sampling and expensive sophisticated methods for detection are less available. Hemodialysis patients have high prevalence of HCV and may resemble sick populations in developing countries in relation to immunosuppression and antibodies production. For these reasons anti-HCV antibodies were assayed in saliva of hemodialysis patients by ImmunoComb II assay that is less laborious, relatively inexpensive and easy to perform If the findings are confirmed by larger studies this method may be useful especially in developing countries. Serum and saliva samples were obtained from 37 hemodialysis patients and assayed by ImmunoComb II kit. In positive PCR patients the saliva test had 100% sensitivity, which was as good as serum anti-HCV Axsym testing. Saliva testing had a similar or better specificity than the serum method.

Aged↗
PubMed2002

Human cytomegalovirus salivary antibodies as related to stress.

Human cytomegalovirus (HCMV) is prevalent in 50-80% of the population worldwide. After primary infection it remains in a latent state until reactivation. Stressful events induce the release of corticosteroids which activate HCMV. The effect of examination stress on HCMV reactivation among first year female students was studied by detecting the values of HCMV specific salivary IgG and IgA antibodies before, during and after two important examinations. Hepatitis A virus (HAV) salivary antibodies served as a non-latent virus control. A statistically significant increase in the level of HCMV specific IgG and IgA antibodies was detected in saliva samples collected during the two examinations, as compared with the samples collected one month before them and two weeks after the grades were posted (p<0.05), whereas HAV antibody levels did not change significantly.

Adult↗
PubMed2001

Rabbit EPO gene and cDNA: expression of rabbit EPO after intramuscular injection of pDNA.

Erythropoietin (EPO) cDNA was cloned from kidney total RNA of a NZW rabbit. The cDNA comprises a 588-bp open reading frame encoding a 195 amino acid protein with distinguishable regions of high of homology to other mammalian EPOs. Intramuscular injection of mice with a rabbit EPO expression plasmid resulted in a significant hematocrit increase. A rabbit genomic DNA fragment was also cloned using the rabbit EPO cDNA. This 4312-bp genomic DNA fragment contains sequences homologous to the mouse EPO promoter and hypoxia-responsive enhancer. In addition, the genomic DNA also presents a high degree of conservation to other regions involved in hypoxia response. Sequence divergence in the 3' UTR may indicate differences in regulation of mRNA stability or response to low oxygen tension.

Amino Acid Sequence↗
PubMed2001

Epstein-Barr virus specific salivary antibodies as related to stress caused by examinations.

Epstein-Barr virus (EBV) is prevalent in 90% of the population. After primary infection it remains in a latent state and the majority of the virus carriers are asymptomatic during their life. Among the immunocompromized patients such as organ and bone marrow transplant recipients, individuals lacking T cell immunity, and patients treated with corticosteroid, cancer, and AIDS patients EBV primary infection and reactivation can cause life threatening diseases. Immunosupression may occur also during stressful events, which induce corticosteroid release and thus activate EBV. The effect of examination stress on EBV reactivation among female students was studied by detecting the values of EBV specific IgG and IgA salivary antibodies. Sequential saliva samples were obtained from first year female students before, during, and after two important examinations. EBV specific IgG and IgA salivary antibodies were tested by enzyme-linked immunosorbent assay (ELISA). Hepatitis A virus (HAV) salivary antibodies served as a non-latent virus control. A statistically significant increase in the values of EBV specific IgG and IgA antibodies was detected in samples collected during the examinations, as compared to the samples collected two months before and one month after the exams (P < 0.05). HAV antibody levels did not change significantly between the four time points. The menstrual cycle had no significant effect on the results. No significant symptoms were reported during the whole study. These results indicate that among female students who endure stress during academic examinations, a significant increase in EBV specific IgG and IgA salivary antibody values could be detected. EBV reactivation should be confirmed by measuring salivary EBV DNA or infectious virus.

Adult↗
PubMed2001

Electroporation-facilitated delivery of plasmid DNA in skeletal muscle: plasmid dependence of muscle damage and effect of poloxamer 188.

Electroporation has been reported to facilitate naked DNA gene transfer in skeletal muscle, but has also been implicated in the pathogenesis of electrical injuries. To assess the effects of electroporation on gene transfer, mouse quadriceps muscles were injected with the luciferase reporter plasmid VR1255 and electroporated with caliper electrodes. Intramuscular luciferase expression was increased 10- to 70-fold by electroporation, depending on the DNA dose and injection volume used. In the absence of plasmid DNA injection, electroporation of quadriceps muscles resulted in rapid elevations in serum creatine phosphokinase activity, but did not elicit visible muscle damage. However, in muscles injected with plasmid DNA and electroporated, visible lesions consistently developed in the areas proximal to electrode placement when field strengths optimal for gene transfer (300 volts/cm) were applied. The development of muscle lesions was independent of plasmid transgene expression and required the presence of plasmid in the muscle during electroporation. Co-injection of poloxamer 188 (pluronic F68) with VR1255 substantially reduced elevations in serum creatine phosphokinase activity following electroporation, but did not inhibit the development of muscle lesions. In non-electroporated muscles, co-injection of poloxamer 188 increased luciferase expression threefold. Poloxamer 188 may thus constitute a useful excipient for intramuscular delivery of naked DNA.

Animals↗
PubMed2001

Salivary HCV-antibodies; a follow-up cohort study of liver disease patients.

We have recently shown in Liver Clinic patients that saliva instead of serum may be used for anti-HCV detection. As compared to blood withdrawing, saliva is easier to obtain, non invasive, especially for infants. In the present study, sequential determination of serum and salivary anti-HCV was performed in the same cohort for 36 months. Anti-HCV seropositive and seronegative patients were studied. Blood and saliva samples were obtained simultaneously. From the anti-HCV seronegative patients (n=33), 161 sequential serum and 161 matched saliva samples were obtained. All were anti-HCV negative. From the anti-HCV seropositive patients (n=35), 131 sequential serum and 131 matched saliva samples were obtained. All sequential serum samples were anti-HCV positive. Of the saliva samples 126 (96%) were anti-HCV positive and five (4%) were anti-HCV negative. These five samples were obtained from two patients with autoimmune hepatitis and HCV-RNA seronegative by PCR. The results suggest that saliva may serve as a substitute for serum for the detection of anti-HCV antibodies.

Antibodies, Viral↗
PubMed1998

Induction of antigen-specific cytotoxic T lymphocytes in humans by a malaria DNA vaccine.

CD8+ cytotoxic T lymphocytes (CTLs) are critical for protection against intracellular pathogens but often have been difficult to induce by subunit vaccines in animals. DNA vaccines elicit protective CD8+ T cell responses. Malaria-naïve volunteers who were vaccinated with plasmid DNA encoding a malaria protein developed antigen-specific, genetically restricted, CD8+ T cell-dependent CTLs. Responses were directed against all 10 peptides tested and were restricted by six human lymphocyte antigen (HLA) class I alleles. This first demonstration in healthy naïve humans of the induction of CD8+ CTLs by DNA vaccines, including CTLs that were restricted by multiple HLA alleles in the same individual, provides a foundation for further human testing of this potentially revolutionary vaccine technology.

Adult↗
PubMed1998

Hepatitis C virus infection and genotypes in Southern Israel and the Gaza Strip.

The Gaza Strip borders the southern part of Israel and Egypt. There is a remarkable difference in the prevalence of antibodies to hepatitis C virus (HCV) between Israel (0.5%) and Egypt (10%). A few thousand inhabitants cross the borders daily from the Gaza Strip to both countries. The objectives of this study were to investigate the prevalence of HCV infection in the Gaza Strip, an area that was not studied before, and to study HCV transmission in the Gaza Strip by characterizing the genotypes of HCV in Southern Israel and the Gaza Strip and comparing them with those found in Egypt. HCV prevalence in the Gaza Strip was found to be 2.2%, relatively higher than in Israel but lower than in Egypt. The most common genotypes found were type 1 b in Southern Israel and type 4 in the Gaza Strip, corresponding to the most prevalent genotype in Egypt. Similarity between type 4 isolates from the Gaza Strip and Egypt was illustrated further by sequence analysis of the HCV 5' noncoding region (NCR).

Base Sequence↗
PubMed1998

In vitro expression and in vivo immunogenicity of Plasmodium falciparum pre-erythrocytic stage DNA vaccines.

DNA vaccine plasmids were constructed that encoded four pre-erythrocytic antigens from the human malaria parasite Plasmodium falciparum: circumsporozoite protein (PfCSP); sporozoite surface protein 2 (PfSSP2); carboxyl terminus of liver stage antigen 1 (PfLSA-1 c-term); and, exported protein 1 (PfExp-1). Antigen expression was evaluated in vitro by immunoblot analysis of tissue culture cells following transient transfection with each plasmid. Clearly detectable levels of expression depended upon, or were markedly enhanced by, fusion of the antigen encoding sequences in-frame with the initiation complex and peptide leader sequence of human tissue plasminogen activator protein. Mice injected with these plasmids produced antigen specific antibody and cytotoxic T lymphocyte responses. However, the magnitudes of the responses were not always predicted by the in vitro expression assay. The results of this study provided the basis for further testing of these plasmids in primates and the formulation of multi-component pre-erythrocytic DNA vaccines for efficacy testing in human volunteers.

Amino Acid Sequence↗
PubMed1998

HCV antibodies in saliva and urine.

Infection with hepatitis C virus (HCV) is usually established by detection of serum antibodies (anti-HCV). This study was conducted in order to evaluate whether saliva and urine may substitute serum for anti-HCV detection. Serum, saliva, and urine were obtained simultaneously from 141 patients with a variety of liver diseases and from 52 patients with autoimmune diseases (systemic lupus erythematosus n = 27 and rheumatoid arthritis n = 25). The cell free fraction of saliva and urine samples was tested for anti-HCV using a modification of a serum anti-HCV kit. Western blot analysis was used as a confirmation method. Of the patients with liver diseases, 73 were anti-HCV-seropositive. Salivary and urinary anti-HCV could be detected in 66 (90%) and 36 (49%) of the anti-HCV-seropositive patients, respectively. The presence of anti-HCV in saliva or urine was not related to the severity of liver disease. All the anti-HCV-seronegative liver patients were negative for salivary anti-HCV and 22 (32%) had urinary anti-HCV. The patients with autoimmune diseases were all anti-HCV-seronegative. None had detectable salivary anti-HCV while 33 (63%) were positive for urinary anti-HCV. Western Blot analysis confirmed the presence of anti-HCV in all serum and saliva samples tested but only in 2/12 urine samples. The results suggest that saliva, but not urine, may serve as a substitute for serum for the determination of anti-HCV positivity.

Blotting, Western↗
PubMed1998

Comparison of seroprevalences of human herpesvirus-6 and -7 in healthy blood donors from nine countries.

BACKGROUND AND OBJECTIVES: The purpose of the study was to register antibody prevalences of HHV-7 in various locations of the world in comparison to the closely related HHV-6. MATERIALS AND METHODS: Sera of healthy blood donors from nine countries in five continents were titered by indirect immunofluorescent assays using HHV-6 infected HSB2 and HHV-7 infected SupT1 cells. RESULTS: Antibody prevalence for HHV-7 is high (75-98%) in practically all countries except for Northern Japan (44%), with no simple correlation to elevated HHV-6 antibody titers. There were regions of low, intermediate and high mean antibody titers against HHV-7 such as 78.5-91.3 for Belgium, Israel, Japan, USA and Australia, 175.4-182.6 for Mexico and Cologne/Germany, and 389.2 for South Africa for which geographic characteristics may be responsible. CONCLUSION: HHV-7, similar to HHV-6, is a widespread human herpesvirus with elevated antibody titers in the healthy human population essentially everywhere. The data warrant further studies to evaluate its possible pathologic potential, preferentially in persons with defective immune responses.

Adolescent↗
PubMed1997

Malaria DNA vaccines in Aotus monkeys.

In preparation for the development of DNA vaccines designed to produce protective antibodies against Plasmodium falciparum antigens (Ag), we conducted studies to optimize antibody responses in Aotus monkeys after immunization with the P. yoelli circumsporozoite (CSP) DNA vaccine. We demonstrate in Aotus monkeys that an intradermal route of immunization with a PyCSP plasmid DNA vaccine generates antibody responses equivalent to a multiple antigen peptide/adjuvant based vaccine, and that these data support the use of the intradermal route for initial studies of the efficacy of DNA vaccines in inducing protective antibodies against P. falciparum antigens in Aotus monkeys.

Animals↗
PubMed1997

Strategy for development of a pre-erythrocytic Plasmodium falciparum DNA vaccine for human use.

Data generated in the Plasmodium yoelii rodent model indicated that plasmid DNA vaccines encoding the P.yoelii circumsporozoite protein (PyCSP) or 17 kDa hepatocyte erythrocyte protein (PyHEP17) were potent inducers of protective CD8+ T cell responses directed against infected hepatocytes. Immunization with a mixture of these plasmids circumvented the genetic restriction of protective immunity and induced additive protection. A third DNA vaccine encoding the P. yoelii sporozoite surface protein 2 (PySSP2) also induced protection. The P. falciparum genes encoding the homologues of these three protective P. yoelii antigens as well as another P. falciparum gene encoding a protein that is expressed in infected hepatocytes have been chosen for the development of a human vaccine. The optimal plasmid constructs for human use will be selected on the basis of immunogenicity data generated in mice and nonhuman primates. We anticipate that optimization of multi-gene P. falciparum DNA vaccines designed to protect against malaria by inducing CD8+ T cells that target infected hepatocytes will require extensive clinical trials during the coming years.

Animals↗
PubMed1997

Hepatitis B and C viruses serology in patients with SLE.

Sera of 95 patients with SLE were tested for the presence of hepatitis B surface antigen (HBsAg) and anti-hepatitis C antibodies. The results show that HBsAg was not detected in the sera of all of the SLE patients. Only one patient was confirmed to have anti-HCV antibodies, suggesting that chronic infection with hepatitis B and C is not increased in patients with SLE compared with the general population.

Adolescent↗
PubMed1996

Long-term expression of erythropoietin in the systemic circulation of mice after intramuscular injection of a plasmid DNA vector.

Erythropoietin (Epo)-responsive anemia is a common and debilitating complication of chronic renal failure and human immunodeficiency virus infection. Current therapy for this condition involves repeated intravenous or subcutaneous injections of recombinant Epo. In this report, we describe the development of a novel muscle-based gene transfer approach that produces long-term expression of physiologically significant levels of Epo in the systemic circulation of mice. We have constructed a plasmid expression vector, pVRmEpo, that contains the murine Epo cDNA under the transcriptional control of the cytomegalovirus immediate early (CMV-IE) promoter, the CMV-IE 5' untranslated region, and intron A. A single intramuscular (i.m.) injection of as little as 10 micrograms of this plasmid into immunocompetent adult mice produced physiologically significant elevations in serum Epo levels and increased hematocrits from preinjection levels of 48 +/- 0.4% to levels of 64 +/- 3.3% 45 days after injection. Hematocrits in these animals remained elevated at greater than 60% for at least 90 days after a single i.m. injection of 10 micrograms of pVRmEpo. We observed a dose-response relationship between the amount of plasmid DNA injected and subsequent elevations in hematocrits. Mice injected once with 300 micrograms of pVRmEpo displayed 5-fold increased serum Epo levels and elevated hematocrits of 79 +/- 3.3% at 45 days after injection. The i.m. injected plasmid DNA remained localized to the site of injection as assayed by the PCR. We conclude that i.m. injection of plasmid DNA represents a viable nonviral gene transfer method for the treatment of acquired and inherited serum protein deficiencies.

Animals↗
PubMed1996

An improved plasmid DNA expression vector for direct injection into skeletal muscle.

In previous work, the direct injection of 50 micrograms of a plasmid DNA vector encoding firefly luciferase (VR1205) into murine quadriceps muscle produced an average of 6.5 ng of luciferase per muscle at 7 days postinjection. In this report, various elements of the VR1205 vector were modified to increase gene expression levels or to eliminate undesired viral sequences. Expression of the modified vectors was then compared to VR1205 using the intramuscular injection assay. In general, modifications to promoter, enhancer, and intronic sequences either decreased luciferase expression levels or had no effect. However, modifications to the polyadenylation and transcriptional termination sequences, plasmid backbone elements, and the luciferase gene itself each increased luciferase expression levels. The best-expressing vector, designated VR1255, contained a combination of these incrementally beneficial changes. A single intramuscular injection of 50 micrograms of VR1255 produced 300 ng of luciferase at 7 days postinjection, an expression level 46-fold higher than the VR1205 vector (or 22-fold higher, excluding modifications to the luciferase gene) and 154-fold higher than a commercially available luciferase expression vector. Thus, VR1255 represents an improved plasmid DNA vector that may be useful for gene therapy applications.

Animals↗