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H Peretz

Publications and source records attributed to H Peretz.

At least 19 recordsLinked to original sources
PubMed2006

Aragonite crystalline biomatrices support astrocytic tissue formation in vitro and in vivo.

Astrocytes play a pivotal role in the development and function of the central nervous system by regulating synaptic activity and supporting and guiding growing axons. It is therefore a central therapeutic and scientific challenge to develop means to control astrocytic survival and growth. We cultured primary hippocampal astrocytes on a crystalline three-dimensional (3D) aragonite biomatrix prepared from the exoskeleton of the coral Porites lutea. Such culturing led to the formation of astrocytic tissue-like 3D structures in which the cells had a higher survival rate than astrocytes grown in conventional cell culture. Within the pore void areas, multiple layers of astrocytic processes formed concave sheet structures that had no physical contact with the surface. The astrocytes attached to the crystalline perpendicular edges of the crystalline template surface extended processes in 3D and expressed glial fibrillary acidic protein. The astrocytes also expressed gap junctions and developed partly synchronized cytosolic Ca2+ oscillations. Preliminary in vivo models showed that astrocytic networks were also developed when the matrices were implanted into cortical areas of postnatal rat brains. Hence, we suggest that the biomatrix is a biocompatible supportive scaffold for astrocytes and may be exploited in applications for neuronal tissue restoration in injured or diseased central nervous system.

Animals↗
PubMed2006

Diversity of Glanzmann thrombasthenia in southern India: 10 novel mutations identified among 15 unrelated patients.

BACKGROUND: Glanzmann thrombasthenia (GT) is a congenital bleeding disorder caused by either a lack or dysfunction of the platelet integrin alphaIIbbeta3. OBJECTIVES: To determine the molecular basis of GT in patients from southern India. PATIENTS: Fifteen unrelated patients whose diagnosis was consistent with GT were evaluated. RESULTS: Platelet surface expression of alphaIIbbeta3 was < 10%, 10%-50%, and > 50% of controls in five, nine, and one patient(s), respectively. Immunoblotting of the platelet lysates showed no alphaIIb in 14 patients, and no beta3 in 10 patients, although severely reduced in four patients. Platelet fibrinogen was undetectable in 13 patients, and severely reduced in one patient. One patient showed normal surface alphaIIbbeta3 expression, and normal alphaIIb, beta3 and fibrinogen levels in the lysate. Ten novel candidate disease-causing mutations were identified in 11 patients. The missense mutations included Gly128Ser, Ser287Leu, Gly357Ser, Arg520Trp, Leu799Arg in alphaIIb, and Cys575Gly in beta3. We have already shown that Gly128Ser, Ser287Leu, and Gly357Ser mutations variably affect alphaIIbbeta3 surface expression. The Cys575Gly mutation may disrupt the disulphide link with Cys586 to cause the GT phenotype. The molecular pathology of the other missense mutations is not clear. Two nonsense mutations, Trp-16Stop and Glu715Stop in alphaIIb, and a 7-bp deletion (330-336TCCCCAG) in beta3 are predicted to result in truncated proteins. An IVS15(-1)G --> A mutation in alphaIIb induced a cryptic splice site as confirmed by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Thirteen polymorphisms were also identified (five in alphaIIb and eight in beta3), among which five were novel. CONCLUSIONS: While identifying a significant number of novel mutations causing GT, this study confirms the genetic heterogeneity of the disorder in southern India.

Adolescent↗
PubMed2005

Time dependent protection of amifostine from renal and hematopoietic cisplatin induced toxicity.

Efficacy of chemotherapy may be maximized and its toxicity can be minimized if drugs would be administered at specified daily times. The present study was aimed to examine if the protection of amifostine against cisplatin toxicity is time dependent. Amifostine is an organic thiophosphate that protects selectively normal tissues, but not tumors, against the cytotoxicity of DNA binding chemotherapeutic agents such as cisplatin. ICR male mice which were entrained to Light:Dark (L:D) 14:10 were injected (intrapritoneal bolus) for 5 consecutive days with either: cisplatin, cisplatin plus amifostine (administered 30 minutes prior to cisplatin). Injections were given at either 08:00, 13:00, 20:00 or 01:00. Five days later, on day 10, each set of mice was sacrificed (at the same hour corresponds to the injection hour), blood count, blood creatinine and blood urea nitrogen (BUN) were assayed. Cisplatin treated mice exhibited nephrotoxicity, as indicated by increased blood urea nitrogen values and by high blood urea nitrogen to creatinine ratios, as well as myelotoxicity that was indicated by low levels of hemoglobin and platelets. Co-administration of amifostine-cisplatin reversed both, the nephrotoxicity of cisplatin, and its myelosuppressive effects. For BUN, hemoglobin and platelets, maximal protections were observed at 08:00, (p <0.05, p <0.01 and p <0.01 respectively). For BUN/Cr ratio (p <0.05), maximal protections was observed at 13:00. These findings show that amifostine exhibits time dependent protection against cisplatin toxicity and thus it is recommended to use the protector when treatments are given during morning hours. The results also further validate the notion that chronochemotherapy is advantageous at least in reducing drug toxicity and thus should be integrated in the design of clinical protocols.

Amifostine↗
PubMed2005

A 13-bp deletion in alpha(IIb) gene is a founder mutation that predominates in Palestinian-Arab patients with Glanzmann thrombasthenia.

Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder caused by lack or dysfunction of alpha(IIb)beta3 in platelets. GT is relatively frequent in highly inbred populations. We previously identified a 13-bp deletion in the alpha(IIb) gene that causes in-frame deletion of six amino acids in three Palestinian GT patients. In this study, we determined the molecular basis of GT in all known Palestinian patients, examined whether Jordanian patients harbor the same mutations, analyzed whether there is a founder effect for the 13-bp deletion, and determined the mechanism by which the 13-bp deletion abolishes alpha(IIb)beta3 surface expression. Of 11 unrelated Palestinian patients, eight were homozygous for the 13-bp deletion that displayed common ancestry by haplotype analysis, and was estimated to have occurred 300-600 years ago. Expression studies in baby hamster kidney cells showed that substitution of Cys107 or Trp110 located within the deletion caused defective alpha(IIb)beta3 maturation. Substitution of Trp110, but not of Cys107, prevented fibrinogen binding. The other Palestinian patients harbored three novel mutations: G2374 deletion in alpha(IIb) gene, TT1616-7 deletion in beta3 gene, and IVS14: -3C --> G in beta3 gene. The latter mutation caused cryptic splicing predicting an extended cytoplasmic tail of beta3 and was expressed as dysfunctional alpha(IIb)beta(3). None of 15 unrelated Jordanian patients carried any of the described mutations.

Amino Acid Substitution↗
PubMed2004

A common ancestral mutation (C128X) occurring in 11 non-Jewish families from the UK with factor XI deficiency.

Factor XI (FXI) deficiency is a mild bleeding disorder that is particularly common in Ashkenazi Jews, but has been reported in all populations. In Jews, two FXI gene (F11) mutations (a stop codon in exon 5, E117X, type II, and a point mutation in exon 9, F283L, type III) are particularly common, but in other populations a variety of different mutations have been described. In the Basque region of France one mutation, C38R in exon 3, was found in eight of 12 families studied, haplotype analysis suggesting a founder effect. In the course of screening 78 unrelated individuals (including 15 Jewish and 12 Asian) we have found 10 Caucasian non-Jewish patients with the mutation C128X in exon 5. Individuals were investigated because of a personal or family history of bleeding, or finding a prolonged activated partial thromboplastin time. Individuals negative for the type II and type III mutations were screened by a combination of SSCP and heteroduplex analysis. The C128X mutation was found in 10 families (one previously described). Among three individuals with severe FXI deficiency, one was homozygous for the C128X mutation, and two were compound heterozygotes for the C128X and another mutation; other individuals were carriers of the C128X mutation. This is a nonsense mutation producing a truncated protein; individuals have FXI antigen levels concordant with FXI coagulant activity. Haplotype analysis of 11 families, including a further kindred previously reported from the USA, but which originally came from the UK (in which the index patient was homozygous for C128X), suggests a founder effect.

Adolescent↗
PubMed2001

Identification of a region in glycoprotein IIIa involved in subunit association with glycoprotein IIb: further lessons from Iraqi-Jewish Glanzmann thrombasthenia.

The most frequent mutation causing Glanzmann thrombasthenia in Iraqi-Jews (IJ-1) is an 11-bp deletion in exon 13 of the glycoprotein (GP) IIIa gene. This deletion predicts a frameshift that results in the elimination of the C406-C655 disulfide bond and a premature termination codon shortly before the transmembrane domain. To determine the contribution of each of these alterations to the thrombasthenic phenotype, Chinese hamster ovary or baby hamster kidney cells were cotransfected with normal GPIIb complementary DNA (cDNA) and the following GPIIIa cDNAs: normal, cDNA bearing IJ-1 mutation, 2011T>A mutated cDNA predicting C655S (single-letter amino acid codes) substitution, and 2019A>T mutated cDNA predicting Stop657. Elimination of the C406-C655 disulfide bond by C655S substitution did not affect GPIIb/IIIa surface expression or binding of the transfected cells to immobilized fibrinogen, whereas elimination of the transmembrane and cytoplasmic domains in IJ-1 and Stop657 mutants prevented both surface expression and binding of the transfected cells to immobilized fibrinogen. Immunohistochemical staining and immunoprecipitation demonstrated that the elimination of amino acids 657-762 in IJ-1 and Stop657 prevented intracellular GPIIb/IIIa complex formation, and differential immunofluorescence staining of GPIIIa and cellular organelles suggested that the truncated uncomplexed GPIIIa protein was retained in the endoplasmic reticulum. Because the use of GPIIIa Stop693 and normal GPIIb cDNAs yielded GPIIb/IIIa complex formation, though with lower efficiency, it is suggested that amino acids 657-692 of GPIIIa are essential for the intracellular association of GPIIb and GPIIIa. (Blood. 2001;98:1063-1069)

Animals↗
PubMed2001

Cytokine network in nonresponding chronic hepatitis C patients with genotype 1: role of triple therapy with interferon alpha, ribavirin, and ursodeoxycholate.

OBJECTIVE: (i) to characterize the profile of tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), IL 10, Fas-ligand and transforming growth factor beta (TGF beta), chronic hepatitis C (HCV) patients with genotype 1; (ii) to determine the influence of triple therapy (TT) with interferon alpha (IFN alpha) + ribavirin + ursodeoxycholic acid on these cytokines and (iii) to establish the relationship between the pro-inflammatory cytokines and the outcome of treatment. DESIGN AND METHODS: 22 patients infected with HCV-genotype 1 a/b and non responsive to IFN-alpha monotherapy were enrolled in the TT. The controls were 49 HCV naïve patients with genotype 1 a/b. Cytokine levels were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: The baseline TNF alpha values (pg/mL) in the sustained responders (SRs) (63+/-3) were significantly lower than non-responders (NRs) (140+/-16) (p < 0.001). Baseline Fas (ng/mL) levels were also lower in SRs (4.3+/-0.2) than NRs (5.4+/-0.4) (p < 0.05). CONCLUSIONS: Fas and TNF alpha may be used as serological markers of inflammation and effectiveness of therapy.

Adult↗
PubMed2000

Two p16 (CDKN2A) germline mutations in 30 Israeli melanoma families.

Germline mutations in the p16 (CDKN2A) tumour suppressor gene have been linked to inherited predisposition to malignant melanoma (MM). Variable frequencies of p16 germline mutations were reported in different collections of melanoma families but it can be as high as 50%. Here we describe the results of p16 mutation screening in 30 melanoma kindreds in Israel. The entire coding region of the p16 gene, including exons 1, 2 and 3, flanking exon/intron junctions, and a portion of the 3' untranslated (UTR) region of the gene were examined by single-stranded conformation polymorphism (SSCP) analysis and direct sequencing. Two p16 germline mutations were identified: G101W, which has been previously observed in a number of melanoma kindreds, and G122V, a novel missense mutation. Thus, the frequency of mutations identified in this collection of Israeli families was 7%. Functional analysis indicated that the novel G122V variant retained some capacity to interact with cyclin dependent kinases (CDKs) in vitro, yet it was significantly impaired in its ability to cause a G1 cell cycle arrest in human diploid fibroblasts. This partial loss of function is consistent with the predicted impact of G122V substitution on the 3-dimensional structure of the p16 protein.

Adolescent↗
PubMed2000

Molecular characterization of four novel mutations causing factor VII deficiency.

INTRODUCTION: Hereditary deficiency of factor VII (FVII) is a rare coagulation defect. We previously studied the molecular basis of the FVII deficiency in Israeli patients and found that the majority of them bore the Ala244Val mutation. In the present study we further analysed FVII deficient patients. PATIENTS AND METHODS: Three patients with severe FVII deficiency (FVII activity < or =1%) and one with partial deficiency (25%) were studied. In all four patients, the FVII gene was amplified and sequenced. RESULTS: Four novel mutations have been identified: IVS 2+1G-->C Phe 24 deletion, Leu300Pro and Arg277His. Homozygosity for the IVS2+1G-->C mutation was lethal, whereas homozygosity for the Phe 24 deletion was accompanied by a severe bleeding tendency. FVII modeling showed that Phe 24 is located in the Gla domain. Both Arg 277 and Leu 300 are within the catalytic domain, although Arg 277 is also involved in tissue factor binding. CONCLUSION: We have analysed four mutations, two of which (IVS2+1G-->C, Phe 24 deletion) were associated with severe bleeding tendency in the homozygous state, facilitating prenatal diagnosis. Hypothetically, using FVII modeling, Arg 277 replacement by histidine may weaken the tissue factor, while deletion of Phe 24 and Leu300Pro mutation might be associated with abnormal folding of the Gla and catalytic domains, respectively.

Adolescent↗
PubMed2000

XDH gene mutation is the underlying cause of classical xanthinuria: a second report.

BACKGROUND: Classical xanthinuria is a rare autosomal recessive disorder characterized by excessive excretion of xanthine in urine. Type I disease results from the isolated deficiency of xanthine dehydrogenase (XDH), and type II results from dual deficiency of XDH and aldehyde oxidase. The XDH gene has been cloned and localized to chromosome 2p22-23. The aim of this study was to characterize the molecular basis of classical xanthinuria in an Iranian-Jewish family. METHODS: The apparently unrelated parents originated from a community in which consanguineous marriages are common. Subtyping xanthinuria was attempted by homozygosity mapping using microsatellite markers D2S352, D2S367, and D2S2374 in the vicinity of the XDH gene. Mutation detection was accomplished by PCR-SSCP screening of all 36 exons and exon-intron junctions of the XDH gene, followed by direct sequencing and confirmation of sequence alteration by restriction analysis. RESULTS: The index case was homozygous for all three microsatellite markers analyzed. The expected frequency of this genotype in a control population was 0. 0002. These results suggested that xanthinuria in the patient is linked to the XDH gene. Consequently, a 1658insC mutation in exon 16 of the XDH gene was identified. The 1658insC mutation was not detected in 65 control DNA samples. CONCLUSION: A molecular approach to the diagnosis of classical xanthinuria type I in a female patient with profound hypouricemia is described. Linkage of xanthinuria to the XDH locus was demonstrated by homozygosity mapping, and a 1658insC mutation, predicting a truncated inactive XDH protein, was identified. These results reinforce the notion that mutations in the XDH gene are the underlying cause of classical xanthinuria type I.

Amino Acid Sequence↗
PubMed2000

The risk of fragile X premutation expansion is lower in carriers detected by general prenatal screening than in carriers from known fragile X families.

The Fragile X syndrome is the most common cause of inherited mental retardation. For a female premutation carrier, the risk of having a child with a full mutation is positively correlated with the size of the premutation. The current study was performed to evaluate the risk of premutation expansion in the offspring of average-risk carriers detected by general prenatal screening. Over a 4-year period, 9,660 women underwent DNA screening for FMR1 mutation/premutation at the Tel Aviv Sourasky Medical Center. A premutation was defined as a CGG repeat number >50 in the 5' untranslated region (UTR) of exon 1 in the FMR1 gene. The study included only individuals with no family history of X-linked mental retardation or known FMR1 mutations. A premutation was found in 85 women (1 in 114), 68 of whom consented to have prenatal diagnoses in 74 pregnancies. The abnormal allele was transmitted to the offspring in 44 pregnancies. Of these, no change in allele size was noted in 35 pregnancies (79.6%), and expansion within premutation range was evident in 4 pregnancies (9%). In 5 pregnancies (11.4%), expansion to the full mutation was noted. This occurred only in carriers having more than 90 repeats. We conclude that the likelihood of Fragile X premutation expansion to full mutation is significantly lower in individuals ascertained by general prenatal carrier testing than in those from known Fragile X families.

Female↗
PubMed1999

The human platelet alphaIIb gene is not closely linked to its integrin partner beta3.

alphaIIbb3 integrin is a heterodimeric receptor facilitating platelet aggregation. Both genes are on chromosome 17q21.32. Intergenic distance between them has been reported to be 125 to 260 kilobasepairs (kb) by pulsed-field gel electrophoresis (PFGE) genomic analysis, suggesting that they may be regulated coordinately during megakaryopoiesis. In contrast, other studies suggest these genes are greater than 2.0 megabasepairs (mb) apart. Because of the potential biological implications of having these two megakaryocytic-specific genes contiguous, we attempted to resolve this discrepancy. Taking advantage of large kindreds with mutations in either alphaIIb or beta3, we have developed a genetic linkage map between the thyroid receptor hormone-1 gene (THRA1) and beta3 as follows: cen-THRA1-BRCA1-D17S579/alphaIIb-beta3-qte r, with a distance of 1.3 centiMorgans (cM) between alphaIIb and beta3 and the two genes being oriented in the same direction. PFGE genomic and YAC clone analysis showed that the beta3 gene is distal and >/=365 kb upstream of alphaIIb. Additional restriction mapping shows alphaIIb is linked to the erythrocyte band 3 (EPB3) gene, and beta3 to the homeobox HOX2b gene. Analysis of alphaIIb(+)-BAC and P1 clones confirm that the EPB3 gene is approximately 110 kb downstream of the alphaIIb gene. Sequencing the region surrounding the human alphaIIb locus showed the Granulin gene approximately 18 kb downstream to alphaIIb, and the KIAA0553 gene approximately 5.7 kb upstream. This organization is conserved in the murine sequence. These studies show that alphaIIb and beta3 are not closely linked, with alphaIIb flanked by nonmegakaryocytic genes, and imply that they are unlikely to share common regulatory domains during megakaryopoiesis.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1999

Age estimates of two common mutations causing factor XI deficiency: recent genetic drift is not necessary for elevated disease incidence among Ashkenazi Jews.

The type II and type III mutations at the FXI locus, which cause coagulation factor XI deficiency, have high frequencies in Jewish populations. The type III mutation is largely restricted to Ashkenazi Jews, but the type II mutation is observed at high frequency in both Ashkenazi and Iraqi Jews, suggesting the possibility that the mutation appeared before the separation of these communities. Here we report estimates of the ages of the type II and type III mutations, based on the observed distribution of allelic variants at a flanking microsatellite marker (D4S171). The results are consistent with a recent origin for the type III mutation but suggest that the type II mutation appeared >120 generations ago. This finding demonstrates that the high frequency of the type II mutation among Jews is independent of the demographic upheavals among Ashkenazi Jews in the 16th and 17th centuries.

Alleles↗
PubMed1999

Mendelian diseases among Roman Jews: implications for the origins of disease alleles.

The Roman Jewish community has been historically continuous in Rome since pre-Christian times and may have been progenitor to the Ashkenazi Jewish community. Despite a history of endogamy over the past 2000 yr, the historical record suggests that there was admixture with Ashkenazi and Sephardic Jews during the Middle Ages. To determine whether Roman and Ashkenazi Jews shared common signature mutations, we tested a group of 107 Roman Jews, representing 176 haploid sets of chromosomes. No mutations were found for Bloom syndrome, BRCA1, BRCA2, Canavan disease, Fanconi anemia complementation group C, or Tay-Sachs disease. Two unrelated individuals were positive for the 3849 + 10C->T cystic fibrosis mutation; one carried the N370S Gaucher disease mutation, and one carried the connexin 26 167delT mutation. Each of these was shown to be associated with the same haplotype of tightly linked microsatellite markers as that found among Ashkenazi Jews. In addition, 14 individuals had mutations in the familial Mediterranean fever gene and three unrelated individuals carried the factor XI type III mutation previously observed exclusively among Ashkenazi Jews. These findings suggest that the Gaucher, connexin 26, and familial Mediterranean fever mutations are over 2000 yr old, that the cystic fibrosis 3849 + 10kb C->T and factor XI type III mutations had a common origin in Ashkenazi and Roman Jews, and that other mutations prevalent among Ashkenazi Jews are of more recent origin.

Alleles↗
PubMed1998

A single genetic origin for the common prothrombotic G20210A polymorphism in the prothrombin gene.

The polymorphism G20210A in the 3' untranslated region of the prothrombin gene is associated with an increased level of factor II activity and confers a twofold to fivefold increase in the risk for venous thromboembolism. Among Caucasian populations, the prevalence of factor II G20210A heterozygotes is 1% to 6%, whereas in non-Caucasian populations it is very rare or absent. The aim of the present study was to discern whether factor II G20210A originated from a single or recurrent mutational events. Allele frequencies of four dimorphisms spanning 16 of 21 kb of the factor II gene were determined in 133 unrelated Caucasian subjects of Jewish, Austrian, and French origins who bore factor II G20210A (10 homozygotes and 123 heterozygotes) and 110 Caucasian controls. Remarkable differences in the allele frequencies for each dimorphism were observed between the study groups (P = .0007 or less), indicating strong linkage disequilibrium and suggesting a founder effect. Indeed, a founder haplotype was present in 68% of 20210A mutant alleles and only in 34% of 20210G normal alleles (P < .0001). These data strongly support a single origin for factor II G20210A that probably occurred after the divergence of Africans from non-Africans and of Caucasoid from Mongoloid subpopulations.

Africa, Northern↗
PubMed1998

Prenatal diagnosis of Glanzmann thrombasthenia using the polymorphic markers BRCA1 and THRA1 on chromosome 17.

Glanzmann thrombasthenia is an autosomal recessive bleeding disorder caused by mutations in the genes encoding platelet GPIIb or GPIIIa. Both genes map to chromosome 17q21 and polymorphisms within this chromosomal region have been identified. In the current study, prenatal diagnosis was performed for a family that already had one affected child, patient 1, who had a compound heterozygous mutation in GPIIb. At the time of prenatal diagnosis, the maternal GPIIb mutation had been identified but the paternal GPIIb mutation was unknown. By sequence analysis, the fetus was identified as a carrier of the mother's mutation. To determine the probability of the fetus inheriting the father's mutation, haplotype analysis of DNA samples from the fetus, mother, father and affected child were performed using polymorphic markers on chromosome 17q12-q21. These markers included polymorphisms within the thyroid hormone receptor alpha1 gene (THRA1), the breast cancer gene (BRCA1), GPIIb, GPIIIa, and an anonymous marker D17S579. Heterozygosity within the THRA1, BRCA1 and GPIIIa polymorphic markers predicted that the fetus carried the father's normal allele. Based on genetic linkage studies, no recombination was identified with any of the informative markers, and from the map distance between GPIIb and BRCA1 the accuracy of diagnosis was predicted to be >98%. The father's mutation was subsequently identified and direct sequence analysis of fetal DNA confirmed that the fetus did not inherit the fathers' mutant allele.

BRCA1 Protein↗