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Orgad S, Loewenthal R, Gazit E, Sadetzki S, Novikov I, Carp H. The prognostic value of anti-paternal antibodies and leukocyte immunizations on the proportion of live births in couples with consecutive recurrent miscarriages. Hum Reprod 1999; 14:2974-9. [PMID: 10601081 DOI: 10.1093/humrep/14.12.2974] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Anti-paternal antibodies directed towards paternal leukocytes have been used to predict the prognosis for the subsequent pregnancy in women with consecutive recurrent miscarriages (CRM) and also to determine if the patient has become immune after paternal leukocyte immunization. The predictive value is controversial, as these antibodies are not essential for pregnancy to develop, and only occur in a minority of parous women. This study tried to determine the predictive value of these antibodies when assessed separately for women with five or more abortions and compared to women with three or four abortions. The patients were assessed separately so that the higher live birth rate in the latter group would not obscure meaningful results in the former group with a poor prognosis. Antibody production, whether spontaneous, or induced by immunization, raised the live birth rate in primary and tertiary aborters with three, four, five or more abortions. Anti-paternal antibodies increased the proportion of live births from 18.5 to 53. 7% (P </= 0.01) and from 44.4 to 67.5% (P </= 0.001) in primary aborters with >/= 5 CRM and 3-4 CRM respectively. Both immunization with paternal leukocytes per se and the ability to express anti-paternal antibodies were associated with an increased proportion of live births in the next pregnancy. Multivariate analysis showed that that the odds ratio for a live birth was approximately four times greater in women who were immunized and produced anti-paternal antibodies than in control patients. The lack of anti-paternal antibodies at initial testing could serve as a marker for the benefit of immunization with paternal leukocytes; the subsequent presence as a prognostic marker for the subsequent pregnancy.
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Gross MD, Ormianer Z, Moshe K, Gazit E. Integrated electromyography of the masseter on incremental opening and closing with audio biofeedback: a study on mandibular posture. INT J PROSTHODONT 1999; 12:419-25. [PMID: 10709523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
PURPOSE The purpose of this study was to test the hypothesis of a minimum electromyographic (EMG) rest position based on masseter surface EMG recordings of incremental opening and closing of the mandible with simultaneous audio EMG biofeedback. MATERIALS AND METHODS Nineteen alert subjects in an upright seated position opened and closed the mandible in 1-mm increments 20 mm interincisally. An electronic recording device allowed each subject to maintain the vertical dimension of each increment while simultaneously reducing right masseteric muscle activity to the minimum possible level using audio EMG biofeedback. Integrated EMG masseteric activity was recorded at each static opening and closing increment. RESULTS A mean plateau of integrated EMG output for all subjects with no minimum EMG point or circumscribed minimum EMG range for any of the nineteen subjects was shown. Analysis of variance for repeated measures showed no difference in opening and closing EMG levels (P = 0.27) and no interaction between opening, closing, and change in vertical dimension (P < 0.0001). CONCLUSION These results, with those of other studies, raise questions regarding the validity of the concept of a unique physiologic rest position of the mandible with the masseter or associated muscles at minimum muscle activity. The idea of overlapping postural ranges appears to be more appropriate.
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Meged S, Stein D, Sitrota P, Melamed Y, Elizur A, Shmuelian I, Gazit E. Human leukocyte antigen typing, response to neuroleptics, and clozapine-induced agranulocytosis in jewish Israeli schizophrenic patients. Int Clin Psychopharmacol 1999; 14:305-12. [PMID: 10529073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The atypical antipsychotic agent clozapine is known to be effective in schizophrenic patients refractory to other medications; however, it induces agranulocytosis in approximately 1-2%. In Jews, this complication is associated with the haplotype HLA B38,DR4,DQ3. The aim of the present study was to determine which human leukocyte antigen (HLA) antigens are involved in clozapine-induced agranulocytosis. We performed HLA typing in 88 Jewish Israeli schizophrenic patients and in 127 ethnically matched healthy individuals. Thirty-eight patients responsive to standard antipsychotic medications were treated with haloperidol, and 50 refractory patients received clozapine. A trend was noted for elevated rates of HLA B38 among control individuals and clozapine-treated patients of Ashkenazi origin compared to individuals of non-Ashkenazi origin, but the findings failed to reach statistical significance. No association was found between HLA class I antigens and the response to haloperidol or clozapine. Neutropenia developed in two clozapine-treated patients and agranulocytosis in one. Two of these three patients were of Ashkenazi origin, and both demonstrated the HLA B38 phenotype. Although the findings did not reach a statistical significance because of the small number of patients, they may support an association between clozapine-induced neutropenia/agranulocytosis and Ashkenazi origin and the HLA B38 phenotype. The rate of agranulocytosis in our sample (2%) is similar to the usual cumulative risk of agranulocytosis but in contrast to its high frequency among Jewish American patients. One possible explanation for this difference is the high rate of Ashkenazi patients in the American sample and the preponderance of non-Ashkenazi patients in our population.
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Gazit E, Sauer RT. The Doc toxin and Phd antidote proteins of the bacteriophage P1 plasmid addiction system form a heterotrimeric complex. J Biol Chem 1999; 274:16813-8. [PMID: 10358024 DOI: 10.1074/jbc.274.24.16813] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The toxin (Doc) and antidote (Phd) proteins of the plasmid addiction system of bacteriophage P1 were purified as a complex. Cocrystals of the complex contained a 2:1 molar ratio of Phd:Doc as assayed by dye binding following SDS-polyacrylamide gel electrophoresis and as determined by amino acid analysis. Gel filtration and analytical ultracentrifugation revealed that the two addiction proteins interact in solution to form a P2D trimer composed of one Doc and two Phd molecules. These results support a model in which Phd inhibits the toxic activity of Doc by direct binding. Circular dichroism experiments showed that changes in secondary structure accompany formation of the heterotrimeric complex, raising the possibility that Phd may act by an allosteric mechanism. Studies of Phd and Doc molecules labeled with fluorescent energy donor and acceptor groups gave an equilibrium dissociation constant of about 0.8 microM(2) and a very short, sub second half-life of complex dissociation. As a consequence, low concentrations of free Doc toxin are likely to be present both transiently and in the steady state in cells containing the Phd antidote, making mechanisms of single-hit Doc toxicity improbable.
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80
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Merhav HJ, Landau M, Gat A, Gazit E, Baratz M, Bialy-Golan A, Konikof F, Bril S, Nakache R. Graft versus host disease in a liver transplant patient with hepatitis B and hepatocellular carcinoma. Transplant Proc 1999; 31:1890-1. [PMID: 10371987 DOI: 10.1016/s0041-1345(99)00141-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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81
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Loewenthal R, Shmuelian I, Efter T, Avishai O, Kalt R, Moskovich Y, Gazit E. Detection of anti-HLA antibodies by enzyme-linked immunosorbent assay, fluorescence activated cell sorter and microlymphocytotoxicity testing: a comparison of sensitivities and suggestions for standardization of ELISA. Transplant Proc 1999; 31:1918-9. [PMID: 10372001 DOI: 10.1016/s0041-1345(99)00155-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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82
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Gazit E, Sauer RT. Stability and DNA binding of the phd protein of the phage P1 plasmid addiction system. J Biol Chem 1999; 274:2652-7. [PMID: 9915794 DOI: 10.1074/jbc.274.5.2652] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The plasmid addiction module of bacteriophage P1 encodes two proteins, Doc, a toxin that is stable to proteolytic degradation, and Phd, the toxin's antidote that is proteolytically unstable. Phd has been shown to autoregulate its expression by specific DNA binding. Here, we investigate the secondary structure and thermal stability of Phd, the effect of operator DNA binding on the structure and stability of Phd, and the stoichiometry, affinity, and cooperativity of Phd binding to operator subsites and intact operator DNA. Phd folds as a monomer at low temperatures or in the presence of osmolytes but exists predominantly in an unfolded conformation at 37 degreesC. The native state of Phd is stabilized by operator binding. Two Phd monomers bind to each operator subsite, and four monomers bind to the intact operator. The subsite binding reaction shows a second-order dependence on protein concentration and monomer-bound DNA species are unpopulated, suggesting that two Phd molecules bind cooperatively to each operator subsite. In intact operator binding experiments, both dimer-bound and tetramer-bound DNA species are populated, and binding occurs at protein concentrations similar to those required for subsite binding, suggesting that there is no significant dimer-dimer cooperativity.
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83
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Augarten A, Katznelson D, Dubenbaum L, Doolman R, Sela BA, Lusky A, Szeinberg A, Kerem BS, Paret G, Gazit E, Sack J, Yahav Y. Serum lipase levels pre and post Lundh meal: evaluation of exocrine pancreatic status in cystic fibrosis. INTERNATIONAL JOURNAL OF CLINICAL & LABORATORY RESEARCH 1999; 28:226-9. [PMID: 9879495 DOI: 10.1007/s005990050049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Determination of pancreatic function is essential in cystic fibrosis. The most-reliable method is by measuring pancreatic enzymes in the duodenum following intravenous or oral stimulation. However, this is invasive, time consuming, and expensive. Indirect tests are non-invasive but lack accuracy. This study examines a simple test which combines pancreatic stimulation by Lundh meal and sequential serum lipase measurements. The test was performed on three groups: group A, 36 cystic fibrosis patients carrying two mutations associated with severe disease and pancreatic insufficiency (delta F508, W1282X, G542X, N1303K, S549R); group B, 8 compound heterozygote cystic fibrosis patients carrying one mutation causing mild disease with pancreatic sufficiency (3849 + 10 kb C-->T); group C, 17 healthy individuals. Basal lipase levels were 2-16.5, 16.4-73, and 8.5-27.8 U/l in groups A, B, and C, respectively, with some overlapping between groups. There were three patterns of lipase activity (1) consistently low levels (group A) suggested a severely affected insufficient pancreas; (2) normal basal levels followed by a linear rise peaking 30 min after the meal (found in 16 of 17 healthy individuals and 3 patients of group B) reflecting an unaffected sufficient pancreas; (3) elevated lipase levels not influenced by the meal (5 patients of group B). This reflects an ongoing destructive process in the pancreas which will eventually result in conversion from pancreatic sufficiency to pancreatic insufficiency. Hence serum lipase activity prior to and 30 min after Lundh meal is a good indicator of pancreatic status allowing categorization of cystic fibrosis patients as pancreatic insufficient, pancreatic sufficient, or pancreatic sufficient with late conversion to insufficiency.
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84
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Gazit E, La Rocca P, Sansom MS, Shai Y. The structure and organization within the membrane of the helices composing the pore-forming domain of Bacillus thuringiensis delta-endotoxin are consistent with an "umbrella-like" structure of the pore. Proc Natl Acad Sci U S A 1998; 95:12289-94. [PMID: 9770479 PMCID: PMC22824 DOI: 10.1073/pnas.95.21.12289] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/1998] [Accepted: 08/19/1998] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to elucidate the mechanism of membrane insertion and the structural organization of pores formed by Bacillus thuringiensis delta-endotoxin. We determined the relative affinities for membranes of peptides corresponding to the seven helices that compose the toxin pore-forming domain, their modes of membrane interaction, their structures within membranes, and their orientations relative to the membrane normal. In addition, we used resonance energy transfer measurements of all possible combinatorial pairs of membrane-bound helices to map the network of interactions between helices in their membrane-bound state. The interaction of the helices with the bilayer membrane was also probed by a Monte Carlo simulation protocol to determine lowest-energy orientations. Our results are consistent with a situation in which helices alpha4 and alpha5 insert into the membrane as a helical hairpin in an antiparallel manner, while the other helices lie on the membrane surface like the ribs of an umbrella (the "umbrella model"). Our results also support the suggestion that alpha7 may serve as a binding sensor to initiate the structural rearrangement of the pore-forming domain.
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85
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Gazit E, Lubomirov L, Munakov O, Topper A, Frydman M, Fried K, Borochovitz Z, Dangoor N, Bogolubov A, Carp HJ. Distribution of CAG repeats in normal and Huntington's disease patients in Israel. Clin Genet 1998; 54:250-1. [PMID: 9788733 DOI: 10.1111/j.1399-0004.1998.tb04296.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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86
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Gross M, Nemcovsky C, Tabibian Y, Gazit E. The effect of three different recording materials on the reproducibility of condylar guidance registrations in three semi-adjustable articulators. J Oral Rehabil 1998; 25:204-8. [PMID: 9578229 DOI: 10.1046/j.1365-2842.1998.00225.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sagittal condylar guide settings of three semi-adjustable articulators: WhipMix, Hanau 158 and Denar Mark II were compared using registrations of base plate wax, copper wax and self-curing acrylic resin in two subjects. Four-way ANOVA showed differences between instruments (P < 0.0001), materials (P < 00001), registrations (P < 0.0001), and no difference between operators. Mean differences between materials were 3 degrees and 6 degrees within the range of registration and articulator variability. Denar Mark II gave the highest values, Hanau 158 the lowest with pantronic values generally lower than articulator settings. Neither acrylic nor copper wax were superior to base plate wax. This and previous studies show low reproducibility and variability between instruments, occlusal records and registration material.
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87
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Monakov O, Shemesh E, Bar-Meir S, Gazit E. Novel nonsense mutation in exon 15 of the APC gene in one Jewish family. Hum Mutat 1998; Suppl 1:S55. [PMID: 9452040 DOI: 10.1002/humu.1380110119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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88
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Valevski A, Klein T, Gazit E, Meged S, Stein D, Elizur A, Narinsky ER, Kutzuk D, Weizman A. HLA-B38 and clozapine-induced agranulocytosis in Israeli Jewish schizophrenic patients. EUROPEAN JOURNAL OF IMMUNOGENETICS : OFFICIAL JOURNAL OF THE BRITISH SOCIETY FOR HISTOCOMPATIBILITY AND IMMUNOGENETICS 1998; 25:11-3. [PMID: 9587740 DOI: 10.1046/j.1365-2370.1998.00091.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To further substantiate reports of an association between the major histocompatibility complex subtypes and clozapine-induced agranulocytosis, HLA typing was performed in 61 Jewish Israeli schizophrenic patients, in 11 of whom agranulocytosis developed following clozapine treatment and in 50 (controls) of whom it did not. Of the 11 agranulocytosis patients, seven (63%) were of Ashkenazi origin and four (37%) of Sephardi origin. There was no difference in ethnic origin between the arganulocytosis and non-agranulocytosis groups (chi 2 = 2.4, d.f. = 1, P = 0.11), although the agranulocytosis patients had a higher frequency of the HLA B38 antigen (8/11 or 72% vs. 6/50 or 12%; chi 2 = 18.7, d.f. = 1, P < 0.001). These results suggest that major histocompatibility complex gene products could be involved in clozapine-mediated haematological complications.
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89
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Tishler M, Maran R, Langevitz P, Livneh A, Gazit E, Gilburd B, Youinou P, Shoenfeld Y. Antiperinuclear factor--clinical, serological and genetic correlates in Israeli patients with rheumatoid arthritis. Rheumatol Int 1998; 17:141-3. [PMID: 9440144 DOI: 10.1007/s002960050025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The possible association between the presence of antiperinuclear factor (APF) and clinical and genetic parameters was investigated in 54 Israeli patients with rheumatoid arthritis (RA). Rheumatoid factor (RF) was detected in the sera of 43 patients (80%) and APF was positive in 33 (61%). No significant statistical differences were found in the presence of HLA-DR4 and/or DR1 between APF-positive and -negative patients. Furthermore, neither the Ritchie articular index nor the patient's functional class correlated with the presence of APF. The results of our study suggested that although Israeli patients have a different genetic background, the presence and behaviour of APF is similar to that of other Caucasian populations.
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90
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Gazit E, Burshtein N, Ellar DJ, Sawyer T, Shai Y. Bacillus thuringiensis cytolytic toxin associates specifically with its synthetic helices A and C in the membrane bound state. Implications for the assembly of oligomeric transmembrane pores. Biochemistry 1997; 36:15546-54. [PMID: 9398283 DOI: 10.1021/bi9707584] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The CytA toxin exerts its activity by the formation of pores within target cell membranes. However, the exact mechanism of pore formation and the structural elements that are involved in the toxic activity are yet to be determined. Recently, the structure of the highly similar CytB toxin was solved (Li et al., 1996), and a beta-barrel was suggested as a possible structure of the pores. Due to the similarity between the toxins, the existence and positioning of alpha-helices and beta-sheets in CytA were predicted from the alignment of the sequences. Here peptides corresponding to beta5, beta6, and beta7 strands, to a conserved nonhelical region of the CytA toxin (P149-170), to helices B and D, and to an analogue of helix A were synthesized, fluorescently labeled, and characterized. We found that, unlike helices A and C (Gazit and Shai, 1993), neither the beta-strand peptides nor helix B could interact with lipid membranes, whereas P149-170 and helix D bind the membrane weakly. Membrane permeation experiments suggested that CytA toxin exerts its activity by aggregation of several monomers. To learn about the structural elements that may mediate CytA oligomerization, the ability of the synthetic peptides to interact with membrane-bound CytA was studied. Helices A and C, but not the beta-strands, helix D, or a control peptide, caused a large increase in the fluorescence of membrane-bound fluorescein-labeled CytA, whereas helix B had only a slight effect. Moreover, the addition of rearranged helix A, a peptide with the same composition as helix A, but with only two pairs of amino acids rearranged, did not affect the fluorescence. The addition of unlabeled CytA also caused an increase in the fluorescence intensity, further demonstrating the interaction between CytA monomers within the membrane. Taken together, our results provide further support for the suggestion that the CytA toxin self-assembles within membrane and that helices A and C are major structural elements involved in the membrane interaction and intermolecular assembly of the toxin.
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91
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Gross M, Gavish A, Calderon S, Gazit E. The coronoid process as a cause of mandibular hypomobility--case reports. J Oral Rehabil 1997; 24:776-81. [PMID: 9372469 DOI: 10.1046/j.1365-2842.1997.00556.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In an attempt to draw the clinician's attention to the coronoid process site while evaluating the aetiology of the restriction of mandibular opening, four cases are illustrated. These cases represent a diversity of causes hampering the free rotational movement of the coronoid process in space during jaw function. Case 1 is an example of unilateral hyperplastic coronoid process and osteochondroma; case 2 shows unusually shaped short and divergent coronoid processes combined with a bucally displaced maxillary third molar on one side; cases 3 and 4 represent an anatomical variation of an extremely narrow vestibular space due to the close proximity of the medial aspect of the coronoid process to the distal molar. It is suggested that each clinical examination include the width of the buccal vestibular space while performing mandibular movements.
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Carp HJ, Toder V, Torchinsky A, Portuguese S, Lipitz S, Gazit E, Mashiach S. Allogenic leukocyte immunization after five or more miscarriages. Recurrent Miscarriage Immunotherapy Trialists Group. Hum Reprod 1997; 12:250-5. [PMID: 9070705 DOI: 10.1093/humrep/12.2.250] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Rather than investigate whether paternal leukocyte immunization improves the live birth rate in women with three or more abortions, we analysed the results of patients expected to have a poor outcome in a subsequent pregnancy if untreated, i.e. women with five or more abortions and no anti-paternal complement-dependent antibody (APCA) at initial testing. The analysis included the results of patients treated by us over the last 8 years and the results of randomized and non-randomized trials reported by the Recurrent Miscarriage Immunotherapy Trialists Group. Patients with a previous live birth were classified into two groups: secondary aborters if there was an initial live birth followed by miscarriages, or tertiary aborters if there were miscarriages followed by a live birth and at least three subsequent miscarriages. The results were evaluated separately for primary, secondary and tertiary aborters who demonstrated APCA activity as a result of immunization. The 107 primary aborters had double the live birth rate if immunized, with an overall benefit of 31%. The 45 tertiary aborters had an almost 3-fold increase in the live birth rate, with an absolute benefit of 50%. The number of patients needed to treat to achieve one extra live birth was three to four primary aborters or two tertiary aborters. Immunization had little beneficial effect in secondary aborters but was effective in preventing abortion in primary or tertiary aborters with five or more abortions.
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93
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Livneh A, Renert A, Avishai O, Langevitz P, Gazit E. Lymphocytotoxic antibodies in Israeli patients with rheumatoid arthritis. ISRAEL JOURNAL OF MEDICAL SCIENCES 1997; 33:30-5. [PMID: 9203515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The presence, antigenic specificity, and clinical role of lymphocytotoxic antibodies (LCAs) were studied in 72 Israeli patients with rheumatoid arthritis (RA). Using the microlymphocytotoxicity assay on a cell panel of 47 donors, LCAs were found in 55% of the 72 RA sera, each displaying a distinct pattern of anti-lymphocytic reactivity, mostly against B lymphocytes. Human lymphocytic antigens (HLA) analysis of donors' lymphocytes suggested that activity of LCA-positive RA sera is HLA directed in 60% of cytotoxic sera. The anti-HLA antibodies found were not autoreactive and were not restricted to a particular class I or class II antigen. Relating the presence of LCAs to selective clinical features revealed that LCAs are inversely associated with the presence of an erosive disease (P <0.01) and with the patients' HLA-DQw1 (P <0.01). These findings suggest that LCAs in Israeli patients with RA are very common, multispecific and may have a protective role not mediated through interaction with self-HLA antigens.
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94
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Gazit E, Miller IR, Biggin PC, Sansom MS, Shai Y. Structure and orientation of the mammalian antibacterial peptide cecropin P1 within phospholipid membranes. J Mol Biol 1996; 258:860-70. [PMID: 8637016 DOI: 10.1006/jmbi.1996.0293] [Citation(s) in RCA: 225] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cecropins are positively charged antibacterial peptides that act by permeating the membrane of susceptible bacteria. To gain insight into the mechanism of membrane permeation, the secondary structure and the orientation within phospholipid membranes of the mammalian cecropin P1 (CecP) was studied using attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and molecular dynamics simulations. The shape and frequency of the amide I and II absorption peaks of CecP within acidic PE/PG multibilayers (phosphatidylethanolamine/phosphatidylglycerol) in a 7:3 (w/w) ratio (a phospholipid composition similar to that of many bacterial membranes), indicated that the peptide is predominantly alpha-helical. Polarized ATR-FTIR spectroscopy was used to determine the orientation of the peptide relative to the bilayer normal of phospholipid multibilayers. The ATR dichroic ratio of the amide I band of CecP peptide reconstituted into oriented PE/PG phospholipid membranes indicated that the peptide is preferentially oriented nearly parallel to the surface of the lipid membranes. A similar secondary structure and orientation were found when zwitterionic phosphatidylcholine phospholipids were used. The incorporation of CecP did not significantly change the order parameters of the acyl chains of the multibilayer, further suggesting that CecP does not penetrate the hydrocarbon core of the membranes. Molecular dynamics simulations were used to gain insight into possible effects of transmembrane potential on the orientation of CecP relative to the membrane. The simulations appear to confirm that CecP adopts an orientation parallel to the membrane surface and does not insert into the bilayer in response to a cis positive transmembrane voltage difference. Taken together, the results further support a "carpet-like" mechanism, rather than the formation of transmembrane pores, as the mode of action of CecP. According to this model, formation of a layer of peptide monomers on the membrane surface destablizes the phospholipid packing of the membrane leading to its eventual disintegration.
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95
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Carp HJ, Ahiron R, Mashiach S, Schonfeld Y, Gazit E, Toder V. Intravenous immunoglobulin in women with five or more abortions. Am J Reprod Immunol 1996; 35:360-2. [PMID: 8739454 DOI: 10.1111/j.1600-0897.1996.tb00494.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PROBLEM Treatment for recurrent miscarriage has usually been given to all women with three or more abortions of unknown cause. As these patients have a 50-60% subsequent live birth rate, no treatment has been shown to unequivocally improve the live birth rate. Immunoglobulin is the latest treatment to be applied. In order to determine if immunoglobulin improves the live birth rate, we analyzed the results of patients expected to have a poor outcome in the subsequent pregnancy if left untreated, i.e., women with five or more abortions, who have aborted after paternal leucocyte immunization or who continue to abort despite possessing anti-paternal complement dependent antibody (APCA). METHODS A preliminary trial was carried out using immunoglobulin (Sandoglobulin, Sandoz, Switzerland). It was infused at a dose of 400 mg/Kg body weight, in the follicular phase of a cycle in which pregnancy was planned. A booster dose was administered as soon as pregnancy was diagnosed. RESULTS Twelve patients were treated, ten conceived. Five have had subsequent live births. Two infants were premature but their size was appropriate for gestational age. The other three infants delivered at term. CONCLUSIONS This is still too small a group from which to draw definite conclusions about the efficacy of immunoglobulin to prevent abortion. However, five live births in ten patients is an encouraging result, especially when the expected poor obstetric outcome is considered. Hence the efficacy of immunoglobulin should be evaluated further in high risk patients.
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Bogolobov A, Frydmann M, Lubomirov L, Borochovitz Z, Fried K, Dangur N, Gazit E. [Huntington's disease: molecular basis and detection of carriers]. HAREFUAH 1996; 130:152-7; 224. [PMID: 8682389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Huntington's disease (HD) results from extensive damage to the nerve cells of the brain cortex and basal ganglia. The gene associated with these changes was mapped in 1983 to the short arm of chromosome 4, at 4p16.3. A decade later it was cloned and the mutation was identified as an increase in the number of CAG repeats in the coding sequence. In the normal gene there are up to 34 repeats but in HD there are more than 36. This is termed dynamic mutation and is found in several other diseases, most of which manifest neurological symptoms. We summarize our studies of 10 families with HD, and 20 individuals with no known history of the disease. Our studies suggest that Jewish patients with HD exhibit the same dynamic gene mutation found in non-Jews. The number of repeats, both in diseased patients and normal controls, is similar to that found in non-Jews. Paternal inheritance was associated with increased severity of symptoms and earlier clinical manifestation, similar to what has been reported. Our experience testing for Huntington gene mutations indicates that this is a relatively simple, reliable and accurate test which can be used in the diagnosis of the disease, in identifying carriers, and for prenatal diagnosis.
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Martinez-Laso J, Gazit E, Gomez-Casado E, Morales P, Martinez-Quiles N, Alvarez M, Martin-Villa JM, Fernandez V, Arnaiz-Villena A. HLA DR and DQ polymorphism in Ashkenazi and non-Ashkenazi Jews: comparison with other Mediterraneans. TISSUE ANTIGENS 1996; 47:63-71. [PMID: 8929714 DOI: 10.1111/j.1399-0039.1996.tb02515.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
HLA-DR and DQ alleles have been detected by DNA typing in Ashkenazi and non-Ashkenazi Jews from Israel. Allele frequencies, characteristic DR/DQ linkage disequilibria, population distances and their corresponding dendrogram by using the Neighbor-Joining method were used to study relatedness between Jewish and other Mediterranean and non Mediterranean populations. Closest relatedness is observed between Ashkenazi and non-Ashkenazi Jews, and, in decreasing order, also with Algerians, Spaniards (including Spanish-Basques), French and Italians. Also, particular characteristic Central European alleles are observed in Ashkenazi Jews and Mediterranean/African alleles in non-Ashkenazi Jews. This is consistent with historical data, Jews being an ancient Mediterranean population, who have had a certain degree of admixture with their 2000-3000 years old neighbors in spite of cultural and religious traditions which have preserved identity outside Israel.
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98
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Peleg L, Gazit E, Goldman B, Akstein E. [Biochemical, molecular and social aspects of carrier screening for Tay-Sachs disease]. HAREFUAH 1995; 129:475-80. [PMID: 8846957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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99
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Nemcovsky CE, Benvenisti A, Gazit E. Variation of skin surface temperature over the masseter muscles in patients with myofascial pain following occlusal splint treatment. J Oral Rehabil 1995; 22:769-73. [PMID: 8606335 DOI: 10.1111/j.1365-2842.1995.tb00221.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The skin surface temperature (SST) over the masseter muscles was measured in 19 patients suffering from myofascial pain (MP) and 20 controls who had no history of any craniomandibular disorder. Seven measurements with intervals of 2 weeks were carried out. MP patients received an occlusal stabilization appliance during their second visit as their only treatment. Clinical symptoms, including muscle sensitivity to palpation, jaw movement and general feeling were evaluated at each visit and compared to baseline. The results indicated that SST in the control group remained almost unchanged throughout the study. In the MP group, the mean temperature decreased during the study after initial treatment. Accordingly, there was a probability of 88.5% that the occlusal appliance treatment in the MP group would cause a decrease of SST over the masseter muscle. A significant relationship between clinical improvement and a decrease of SST was found in the MP group. Temperature recordings with certain limitations could be an objective assessory tool in diagnosis and follow-up of patients with myofascial pain.
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100
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Gazit E, Boman A, Boman HG, Shai Y. Interaction of the mammalian antibacterial peptide cecropin P1 with phospholipid vesicles. Biochemistry 1995; 34:11479-88. [PMID: 7547876 DOI: 10.1021/bi00036a021] [Citation(s) in RCA: 231] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cecropins are positively charged antibacterial polypeptides that were originally isolated from insects. Later on a mammalian homologue, cecropin P1 (CecP), was isolated from pig intestines. While insect cecropins are highly potent against both Gram-negative and Gram-positive bacteria, CecP is as active as insect cecropins against Gram-negative but has reduced activity against Gram-positive bacteria. To gain insight into the mechanism of action of CecP and the molecular basis of its antibacterial specificity, the peptide and its proline incorporated analogue (at the conserved position found in insect cecropins), P22-CecP, were synthesized and labeled on their N-terminal amino-acids with fluorescent probes, without significantly affecting their antibacterial activities. Fluorescence studies indicated that the N-terminal of CecP is located on the surface of phospholipid membranes. Binding experiments revealed that CecP binds acidic phosphatidylserine/phosphatidylcholine (PS/PC) vesicles better than zwitterionic PC vesicles, which correlates with its ability to permeate the former better than the latter. The shape of the binding isotherms suggest that CecP, like insect cecropin, binds phospholipids in a simple, noncooperative manner. However, resonance energy transfer (RET) measurements revealed that, unlike insect cecropins, CecP does not aggregate in the membrane even at relatively high peptide to lipid ratios. The stoichiometry of CecP binding to vesicles suggests that amount of CecP sufficient to form a monolayer causes vesicle permeation. In spite of the incorporation of the conserved proline in P22-CecP, the analogue has reduced antibacterial activity, which correlates with its reduced alpha-helical structure and its lower partitioning and membrane permeating activity with phospholipid vesicles. Taken together, our results support a mechanism in which CecP disrupts the structure of the bacterial membrane by (i) binding of peptide monomers to the acidic surface of the bacterial membrane and (ii) disintegrating the bacterial membrane by disrupting the lipid packing in the bilayers. These results, combined with data reported for other antibacterial polypeptides, suggest that the organization of peptide monomers within phospholipid membranes contributes to Gram-positive/Gram-negative antibacterial specificity.
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