27 results on '"Bomstein, Y."'
Search Results
2. Telomerase activity in ductal carcinoma in situ of the breast
- Author
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Shpitz, B., Zimlichman, S., Zemer, R., Bomstein, Y., Zehavi, T., Liverant, S., Bernehim, J., Kaufman, Z., Klein, E., Shapira, Y., and Klein, A.pitz
- Published
- 1999
- Full Text
- View/download PDF
3. Chemopreventive effect of aspirin on growth of aberrant crypt foci in rats
- Author
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Shpitz, B., Bomstein, Y., Kariv, N., Shalev, M., Buklan, G., and Bernheim, J.
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- 1998
- Full Text
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4. Altered expression of the DNA mismatch repair proteins hMLH1 and hMSH2 in cutaneous dysplastic nevi and malignant melanoma
- Author
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Shpitz, B., Klein, E., Malinger, P., Osmolovsky, G., Gochberg, S., Bomstein, Y., and Bernheim, J.
- Published
- 2005
5. Microsatellite instability in patients with chronic B-cell lymphocytic leukaemia
- Author
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Niv, E, primary, Bomstein, Y, additional, Yuklea, M, additional, and Lishner, M, additional
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- 2005
- Full Text
- View/download PDF
6. Immunoreactivity of p53, Ki-67, and c-erbB-2 in phyllodes tumors of the breast in correlation with clinical and morphologic features
- Author
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Shpitz, B., primary, Bomstein, Y., additional, Sternberg, A., additional, Klein, E., additional, Tiomkin, V., additional, Kaufman, A., additional, Groisman, G., additional, and Bernheim, J., additional
- Published
- 2002
- Full Text
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7. Evaluation of putative molecular biomarkers in abdominal and retroperitoneal leiomyosarcomas
- Author
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Shpitz, B., primary, Tiomkin, V., additional, Bomstein, Y., additional, Gralkin, M., additional, Buklan, H., additional, Bernheim, J., additional, and Klein, E., additional
- Published
- 2001
- Full Text
- View/download PDF
8. DNA-protein crosslinks, a biomarker of exposure to formaldehyde—in vitro and in vivo studies
- Author
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Shaham, J., primary, Bomstein, Y., additional, Meltzer, A., additional, Kaufman, Z., additional, Palma, E., additional, and Ribak, J., additional
- Published
- 1996
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9. Analysis of chromosomal aberrations in large hepatocellular carcinomas by comparative genomic hybridization
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Kitay-Cohen, Y., Amiel, A., Ashur, Y., Fejgin, M. D., Herishanu, Y., Afanasyev, F., Bomstein, Y., and Lishner, M.
- Published
- 2001
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- View/download PDF
10. Comparative genomic hybridization in polycythemia vera and essential thrombocytosis patients
- Author
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Herishanu, Y., Lishner, M., Bomstein, Y., Kitay-Cohen, Y., Fejgin, M. D., Gaber, E., and Amiel, A.
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- 2001
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11. The porphyrinogenic effect of simvastatin in experimental systems
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Schoenfeld, N., primary, Mamet, R., additional, Lurie, Y., additional, Green, P., additional, Bomstein, Y., additional, and Atsmon, A., additional
- Published
- 1989
- Full Text
- View/download PDF
12. Treatment of atopic dermatitis with KAM-3008, a barrier-based, non-steroidal topical cream.
- Author
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Bomstein Y and Rozenblat S
- Subjects
- Administration, Cutaneous, Adult, Aged, Anti-Allergic Agents administration & dosage, Anti-Inflammatory Agents, Non-Steroidal administration & dosage, Antioxidants, Chronic Disease, Dermatologic Agents administration & dosage, Eczema drug therapy, Emollients administration & dosage, Female, Humans, Male, Middle Aged, Plant Extracts administration & dosage, Plant Extracts therapeutic use, Skin drug effects, Skin pathology, Skin Diseases drug therapy, Steroids, Treatment Outcome, Young Adult, Anti-Allergic Agents therapeutic use, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Dermatitis, Atopic drug therapy, Dermatologic Agents therapeutic use, Emollients therapeutic use
- Abstract
Introduction: Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with cutaneous hyper-reactivity to environmental triggers, and is characterized by pruritic eczematous skin lesions. Recent insights into the pathophysiology of AD point to the important role that abnormal barrier permeability plays, which leads to compromised hydration, common micro-organismal colonization and immune dysregulation. Current treatment strategies for AD, such as topical corticosteroids and moisturizers, control the disease symptom's severity and duration. KAM-3008 is a novel, barrier-based, steroid-free, topical cream indicated for the relief of symptoms associated with AD. In addition to moisturizing and emollient ingredients, several herbal extracts have been incorporated into the formulation to enhance its anti-allergic and anti-inflammatory properties., Methods: In this study, the safety and efficacy of KAM-3008 body cream in relieving the symptoms of AD in adult subjects after 7, 14 and 21 days of treatment were investigated using the transepidermal water loss (TEWL), skin hydration and scoring atopic dermatitis (SCORAD) measurements., Results and Conclusions: Based on both the quantitative TEWL and qualitative SCORAD assessments, we found that KAM-3008 body cream is a safe, well-tolerated and efficacious stand-alone treatment for the relief of AD symptoms.
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- 2015
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13. Microsatellite instability in multiple nonfamilial malignancies.
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Niv E, Bomstein Y, Bernheim J, and Lishner M
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- Base Pair Mismatch genetics, Base Sequence, DNA Primers, DNA, Neoplasm genetics, Family, Genetic Markers, Humans, Leukemia genetics, Phenotype, Chromosomal Instability, Hematologic Neoplasms genetics
- Abstract
Development of multiple tumors of different histopathologic types may suggest a profound generalized genetic defect, such as malfunction of DNA mismatch repair (MMR) mechanism. Defects in this mechanism are best reflected in microsatellite instability (MSI). We aimed to determine the role of MSI in a group of patients with dual malignancies and compared the data with that of patients with a single malignancy. Fifty patients were enrolled in the study, of whom 16 patients developed both solid and hematologic nonfamilial malignancies, 18 patients developed a single matched hematologic malignancy, and 16 a single matched solid malignancy. Five microsatellite markers were replicated by polymerase chain reaction (PCR) after DNA extraction from paraffin-embedded tissue blocks and analyzed by the GeneScan Analysis Software. The MSI-high phenotype was defined as instability in at least 40% of the examined loci. A higher prevalence of MSI-high phenotype was found in patients with dual malignancies (31.3%) compared with patients with single hematologic (5.6%) or solid malignancy (6.3%) (P = 0.0498 and 0.07, respectively). In conclusion, defects in DNA MMR mechanism may have an important role in the development of multiple sporadic nonfamilial malignancies.
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- 2006
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14. Microsatellite instability in gastric MALT lymphoma.
- Author
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Niv E, Bomstein Y, Bernheim J, and Lishner M
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- Adult, Aged, Female, Genomic Instability, Humans, Loss of Heterozygosity, Male, Middle Aged, Polymerase Chain Reaction, DNA Repair Enzymes genetics, Lymphoma, B-Cell, Marginal Zone genetics, Microsatellite Repeats genetics, Stomach Neoplasms genetics
- Abstract
The role of microsatellite instability and defects in DNA mismatch repair mechanism in the pathogenesis of gastric lymphoma of mucosa-associated lymphoid tissue (MALT) type is still controversial, as both negative and positive findings have been reported. This may be explained mainly by arbitrary selection of the tested loci, the use of various techniques of microsatellite instability analysis and by different definitions of replication error positive phenotype. The aim of our study was to evaluate the instability at selected microsatellite markers using the GeneScan Analysis Software. DNA from paraffin-embedded tissue blocks of 13 previously untreated patients with localized gastric MALT lymphoma was extracted. Five microsatellite markers, which are located in hMSH2, hMLH1, P16, APC and MLL loci, were selected from the genetic database. We found genetic instability in tumors of 9/13 patients with gastric MALT lymphoma (69%). Seven of them had replication-error-positive phenotype (54%). Microsatellite instability was found in 39% of the samples in the MLL locus, 39% in the APC, 46% in the P16, 23% in the hMLH1 and none in the hMSH2. This study demonstrates that microsatellite instability has more prominent role in pathogenesis of gastric MALT lymphoma than reported to date. We suggest that microsatellite instability should be analyzed with markers adjacent to chromosomal loci that are involved in lymphomas. Our findings support the 'Real Common Target genes' theory of high rate of microsatellite instability in specific genes, which are associated with related tumors.
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- 2004
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15. Features of skin-coincubated macrophages that promote recovery from spinal cord injury.
- Author
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Bomstein Y, Marder JB, Vitner K, Smirnov I, Lisaey G, Butovsky O, Fulga V, and Yoles E
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- Animals, Antigen-Presenting Cells immunology, Antigen-Presenting Cells metabolism, Antigen-Presenting Cells transplantation, Behavior, Animal, Cytokines metabolism, Injections, Intralesional, Macrophage Activation immunology, Macrophages metabolism, Macrophages transplantation, Male, Motor Activity immunology, Rats, Rats, Sprague-Dawley, Spinal Cord Injuries pathology, Spinal Cord Injuries physiopathology, Macrophages immunology, Skin immunology, Spinal Cord Injuries immunology, Spinal Cord Injuries therapy
- Abstract
Uncontrolled inflammation is considered to exacerbate the neuronal loss that follows spinal cord trauma. However, controlled inflammation response appears to be beneficial. Skin-coincubated macrophages injected into contused spinal cord of rats resulted in improved motor recovery and reduced spinal cyst formation. The macrophages express elevated levels of cell-surface molecules CD80, CD86, CD54 and MHC-II, markers characteristic of antigen presenting cells (APCs). Additionally, skin-coincubation elevates secretion of interleukin-1 beta (IL-1 beta) and Brain-Derived Neurotrophic Factor (BDNF), and reduces secretion of tumor necrosis factor alpha (TNF-alpha). We propose that macrophages activated by skin-coincubation bolster neuroprotective immune activity in the spinal cord, making the environment less cytotoxic and less hostile to axonal regeneration.
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- 2003
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16. The antiapoptotic effects of blood constituents in patients with chronic lymphocytic leukemia.
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Bomstein Y, Yuklea M, Radnay J, Shapiro H, Afanasyev F, Yarkoni S, and Lishner M
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- Aged, Aged, 80 and over, Animals, Antigens, CD19 metabolism, B-Lymphocytes pathology, Case-Control Studies, Cattle, Cell Survival, Culture Media, Humans, In Vitro Techniques, Middle Aged, Neoplasm Staging, T-Lymphocytes pathology, Apoptosis, Leukemia, Lymphocytic, Chronic, B-Cell blood, Leukemia, Lymphocytic, Chronic, B-Cell pathology
- Abstract
Objective: Clonal B-lymphocytes of chronic lymphocytic leukemia (B-CLL) are characterized by decreased sensitivity to programmed cell death and, therefore, they accumulate in vivo. However, these malignant cells die rapidly in vitro. In the current study we concentrated on the contribution of autologous serum (AS) and lymphocyte subsets to the survival of the malignant cells in vitro., Methods: Mononuclear cells from the peripheral blood of 26 CLL patients and 24 controls were incubated overnight in the presence or absence of AS and heat-inactivated AS (HI-AS) or fetal calf serum (FCS). Also, isolated B cells were incubated at different concentrations in the presence of AS and/or isolated T cells. The level of apoptosis of CD19+ cells was measured by flow cytometry., Results: Spontaneous apoptosis of unfractionated B-CLL cells incubated with AS, FCS or without serum was significantly lower than the rate of B-cell death in the control group, in similar culture conditions. AS had an antiapoptotic effect on unfractionated B-CLL cells when compared with FCS. The rate of apoptosis of B-CLL cells was directly associated with stage. HI of AS had a variable effect, which was related to the stage of the disease. High concentrations of B cells and the addition of autologous T cells reduced the rate of apoptosis when incubated without serum. The antiapoptotic effect of T cells was most prominent in progressive stages., Conclusions: B-CLL cells exhibit decreased spontaneous apoptosis, which is partially prevented by humoral (AS) and cellular (T cells and B-CLL cells) factors. The equilibrium between apoptotic and antiapoptotic factors changes with disease progression.
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- 2003
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17. Angiogenesis, p53, and c-erbB-2 immunoreactivity and clinicopathological features in male breast cancer.
- Author
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Shpitz B, Bomstein Y, Sternberg A, Klein E, Liverant S, Groisman G, and Bernheim J
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- Adult, Aged, Aged, 80 and over, Breast Neoplasms, Male blood supply, Breast Neoplasms, Male pathology, Humans, Immunohistochemistry, Male, Middle Aged, Neovascularization, Pathologic pathology, Prognosis, Receptors, Estrogen analysis, Survival Analysis, Biomarkers, Tumor analysis, Breast Neoplasms, Male diagnosis, Receptor, ErbB-2 analysis, Tumor Suppressor Protein p53 analysis
- Abstract
Background and Objectives: p53, c-erbB-2, and tumor microvascular density have been shown to be potential prognostic tools in female breast cancer. Our objective was to assess the significance of these biomarkers as prognostic factors in infiltrating male breast cancer., Methods: A retrospective study of expression of p53, c-erbB-2, and tumor microvascular density was done on a group of 26 male breast cancer patients. Biotin-streptavidin immunohistochemical study with specific anti-p53, anti-c-erbB-2, and anti-CD34 antibodies was carried out on paraffin sections of breast carcinoma. The data of expression of the biomarkers were merged with clinicopathological data such as tumor grade, T class, TNM stage, estrogen receptor status, tumor recurrence, and patient survival., Results: p53 and c-erbB-2 were expressed in 46% and 39% of carcinomas, respectively. No correlation was found between positive immunoreactivity of p53, and tumor grade, size, T class, TNM stage, and survival. Nor was any relation found between tumor size, T class, TNM stage, survival, and c-erbB-2 overexpression. c-erbB-2 overexpression was significantly higher in high grade carcinomas. Estrogen receptor (ER) were positive in 21 out of 26 of tumors (81%). No trends were observed between estrogen receptor status and clinicopathological parameters or survival (data not shown). There was a positive correlation between mean microvascular density (MVD), advanced T class, and survival: higher MVD counts were found in patients with advanced tumors and in those who had tumor relapses or died of metastatic disease., Conclusions: This study suggests that tumor microvascular density may serve as a potential prognostic tool in male breast carcinoma., (Copyright 2000 Wiley-Liss, Inc.)
- Published
- 2000
- Full Text
- View/download PDF
18. Topoisomerase IIalpha expression in ductal carcinoma in situ of the breast: a preliminary study.
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Shpitz B, Bomstein Y, Zehavi T, Bernheim J, Liverant S, Kaufman Z, Buklan G, and Klein E
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- Antigens, Neoplasm, DNA-Binding Proteins, Female, Humans, Middle Aged, Necrosis, Receptor, ErbB-2 analysis, Breast Neoplasms enzymology, Carcinoma, Intraductal, Noninfiltrating enzymology, DNA Topoisomerases, Type II biosynthesis, Isoenzymes biosynthesis
- Abstract
Ductal carcinoma in situ (DCIS) of the breast, a precursor lesion of invasive breast cancer, is a heterogeneous disease in terms of histomorphologic features and biologic behavior. Our aim was to assess the proliferative activity, expressed as topoisomerase IIalpha (Topo IIalpha) immunoreactivity and c-erbB-2 expression in relation to morphologic features and architectural pattern of DCIS. The study included 26 DCIS, which were reclassified according to the recommendations of Consensus Conference. Topo-IIalpha and c-erbB-2 immunoreactivity were detected on paraffin sections. Topo IIalpha was consistently negative in normal ductal epithelium. Topo IIalpha-labeling index (Topo IIalpha-LI) was 0.7+/-0.6% for grade I, 4.3+/-3.9% for grade II, and 13.4+/-8.9 for grade III lesions (P<.01). For mixed nuclear grade DCIS, Topo IIalpha-LI was 6.8+/-4.8. There was no difference in Topo IIalpha-LI between different architectural patterns in low- and intermediate-grade lesions. In high nuclear grade DCIS, there was a progressive increase in Topo IIalpha-LI from solid toward cribriform and comedo-type DCIS. Positive c-erbB-2 immunoreactivity was found in 46% of DCIS, being highest in DCIS with high nuclear grade (78%) and in lesions with extensive necrosis. Topo IIalpha-LI was significantly higher in c-erbB-2-positive lesions (Topo IIalpha-LI- 12.4+/-8.5) as compared with negative lesions (Topo IIalpha-LI- 3.9+/-4.5, P<. 0001). Overexpression of c-erbB-2 and Topo IIalpha is associated with poorly differentiated lesions. Proliferative activity in individual ducts of DCIS depended primarily on the nuclear grade and was independent of architectural patterns of individual ducts in architecturally heterogeneous lesions., (Copyright 2000 by W.B. Saunders Company.)
- Published
- 2000
- Full Text
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19. Oncoprotein coexpression in human aberrant crypt foci and minute polypoid lesions of the large bowel.
- Author
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Shpitz B, Bomstein Y, Shalev M, Liverant S, Kaufman Z, Klein E, Mekori Y, and Bernheim J
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- Colon pathology, Colonic Polyps pathology, Humans, Immunohistochemistry, Colon metabolism, Colonic Polyps genetics, Polyploidy
- Abstract
Background: Genetic aberrations observed in the large bowel during the neoplastic progression have a cumulative effect and are responsible for the propagation of the multistep malignant process. In the present study we evaluated the immunoreactivity of c-fos, ras, bcl-2 and p53 in aberrant crypt foci (ACF) and minute polyps of the large bowel obtained from patients with colorectal cancer., Methods: ACF and minute polyps were collected from macroscopically normal colonic mucosa. Protein immunoreactivity was detected on parafin sections utilizing the biotin-streptavidin method on 25 hyperplastic, 10 dysplastic ACF, 5 hyperplastic and 10 dysplastic adenomas., Results: 41% of the lesions displayed positive ras immunoreactivity. bcl-2 immunoreactivity was positive in six minute polyps of which five were neoplastic. fos immunoreactivity was detected in five ACF and seven minute polyps, mainly in dysplastic lesions. Two neoplastic polyps were positive for p53 immunoreactivity. Coexpression of two or more oncoproteins was found with increasing frequency in dysplastic versus hyperplastic lesions and in polypoid lesions versus ACF., Conclusion: Abnormal expression and coexpression in oncoproteins can be identified in the earliest stages of colorectal tumorigenesis and may contribute to the progression of selected lesions during ACF-adenoma-carcinoma sequence.
- Published
- 1999
20. Aberrant crypt foci in human colons: distribution and histomorphologic characteristics.
- Author
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Shpitz B, Bomstein Y, Mekori Y, Cohen R, Kaufman Z, Neufeld D, Galkin M, and Bernheim J
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- Adult, Aged, Aged, 80 and over, Colon metabolism, Colorectal Neoplasms metabolism, Colorectal Neoplasms pathology, Female, Humans, Hyperplasia pathology, Immunohistochemistry, Intestinal Mucosa metabolism, Lymphoid Tissue metabolism, Lymphoid Tissue pathology, Male, Middle Aged, Mitosis, Precancerous Conditions metabolism, Proliferating Cell Nuclear Antigen metabolism, Rectum metabolism, Colon pathology, Colorectal Neoplasms etiology, Intestinal Mucosa pathology, Precancerous Conditions pathology, Rectum pathology
- Abstract
Aberrant crypt foci (ACF) are one of the earliest putative preneoplastic, and in some cases, neoplastic lesions in human colons. These microscopic lesions, identified on methylene blue-stained mucosa with a low-power-magnification microscope, are thought to be closely related to the earliest steps in multistage colonic tumorigenesis. We investigated the distribution pattern and histomorphological features of ACF in 74 patients with sporadic colorectal cancer. The distribution pattern shows a slightly higher prevalence with older age. The prevalence of the ACF in sigmoid colon was significantly higher in patients with colorectal cancer as compared with patients with benign colonic diseases. Also, significantly more ACF were detected in distal parts of the large bowel (descending, sigmoid colon, and rectum) than in proximal parts. Of 42 microdissected lesions, 12 were dysplastic and 30 were hyperplastic foci. The average size of dysplastic lesions was significantly larger than hyperplastic foci. More apoptotic bodies were found in dysplastic lesions. These lesions also showed an upward expansion of proliferative compartment and higher proliferation indices expressed as proliferating cell nuclear antigen-labeling index. Lymphoid follicles were frequently observed in the base of both hyperplastic and dysplastic foci (40% and 66.6%, respectively). The coincidence of lymphoid follicles was 2.5 to 8 times higher than expected. These features may be related to further progression of selected ACF during colorectal tumorigenesis.
- Published
- 1998
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21. Proliferating cell nuclear antigen as a marker of cell kinetics in aberrant crypt foci, hyperplastic polyps, adenomas, and adenocarcinomas of the human colon.
- Author
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Shpitz B, Bomstein Y, Mekori Y, Cohen R, Kaufman Z, Grankin M, and Bernheim J
- Subjects
- Cell Division, Colon pathology, Humans, Hyperplasia diagnosis, Immunohistochemistry, Intestinal Mucosa pathology, Adenocarcinoma diagnosis, Adenomatous Polyps diagnosis, Biomarkers, Tumor analysis, Carcinoma in Situ diagnosis, Colonic Neoplasms diagnosis, Colonic Polyps diagnosis, Proliferating Cell Nuclear Antigen analysis
- Abstract
Background: One of the first steps in multistage colonic carcinogenesis is increased cell proliferation and an upward shift of the proliferation zone of colonic crypts. In the present study, progression in cell kinetics was followed up at all sequential stages of colonic carcinogenesis, starting with aberrant crypt foci (ACF), the earliest putative preneoplastic lesions, hyperplastic and dysplastic polyps, and invasive carcinomas., Materials and Methods: Colonic tissue and tumor specimens were prospectively obtained from 65 patients treated at our hospital for adenocarcinoma or malignant polyps. For identification of ACFs, dissected mucosal strips obtained from patients with colorectal cancer were stained with 0.1% methylene blue and scanned under dissecting microscope. Paraffin-embedded ACFs and macroscopic lesions were serially sectioned, deparaffinized, and stained with a monoclonal antiproliferating cell nuclear antigen (PCNA) antibody. The PCNA-labelling index (PCNA-LI), expressed as a ratio of positively stained nuclei to total nuclei counted, was calculated separately for basal, middle, and upper colonic crypt compartments. A comparison of the PCNA-LI was made for each compartment in normal mucosa, and hyperplastic and dysplastic lesions., Results: A stepwise increase in the PCNA-LI was observed during neoplastic progression of colonic lesions. The two most important variables of increased cell proliferation, expressed as PCNA-LI per crypt compartment, were the presence of dysplasia and the size of dysplastic lesions., Conclusions: In colorectal carcinogenesis, hyperproliferation with upward expansion of proliferative compartment is a characteristic feature at all stages of malignant progression.
- Published
- 1997
- Full Text
- View/download PDF
22. Enhanced sensitivity of P-glycoprotein-positive multidrug resistant tumor cells to complement-mediated lysis.
- Author
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Bomstein Y and Fishelson Z
- Subjects
- CD55 Antigens metabolism, Complement C3b metabolism, Complement C9 metabolism, Complement Membrane Attack Complex metabolism, Cytotoxicity, Immunologic, Humans, Protein Binding, Tumor Cells, Cultured, ATP Binding Cassette Transporter, Subfamily B, Member 1 immunology, Complement System Proteins physiology, Drug Resistance, Multiple
- Abstract
The interaction of KB-V1, a multidrug resistant (MDR) variant of the KB-3-1 human oral carcinoma, with human complement was investigated. KB-V1 cells were found to be more sensitive than KB-3-1 cells to complement-mediated lysis. Detailed analysis of the capacity of KB cells to activate human complement demonstrated that both C3b deposition and formation of the membrane attack complex (MAC) are higher on KB-V1 than on KB-3-1 cells. Furthermore, the MAC formed on KB-V1 cells, but not on KB-3-1 cells, was found to be resistant to trypsin treatment, i.e. more stably inserted into the plasma membrane. Immunofluorescence analysis by flow cytometry showed that KB-V1 cells express less decay-accelerating factor (DAF, CD55) than KB-3-1 cells. Two other complement regulatory proteins, membrane cofactor protein (MCP, CD46) and CD59 are expressed to a similar extent on both KB-V1 and KB-3-1 cells. Treatment of KB-V1 cells with neutralizing anti-P-glycoprotein (P-gp) monoclonal antibodies reduced their sensitivity to complement. In addition, KB-V1 revertants which cease to express P-gp become more resistant to complement. These results indicate that multiple factors, such as reduced expression of DAF, enhanced deposition of C3b and increased binding and stability of the MAC may contribute to the increased complement sensitivity of KB-V1 cells. It is suggested that P-gp is responsible for the complement-sensitive phenotype of KB-V1 cells.
- Published
- 1997
- Full Text
- View/download PDF
23. DNA-Protein Crosslinks and Sister Chromatid Exchanges as Biomarkers of Exposure to Formaldehyde.
- Author
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Shaham J, Bomstein Y, Melzer A, and Ribak J
- Abstract
Formaldehyde is classified as a probable human carcinogen. DNA-protein crosslinks (DPCs) and sister chromatid exchanges (SCEs) may represent early lesions in the carcinogenic process. The authors examined the DPCs and SCEs in peripheral-blood lymphocytes of 12 and 13 workers exposed to formaldehyde and eight and 20 unexposed workers, respectively. The amounts of DPCs and SCEs in the exposed and the unexposed differed significantly after adjustment for smoking. There was a linear relationship between years of exposure and the amounts of DPC and SCE. The authors conclude that the data indicate a possible mechanism of carcinogenicity of formaldehyde, and that formaldehyde is mutagenic to humans. These results support the use of DPCs as a biomarker of occupational exposure to formaldehyde and to detect high-risk populations for secondary prevention.
- Published
- 1997
- Full Text
- View/download PDF
24. Release of immunosuppressive factor(s) by MOPC-315 murine plasmacytoma cells: a possible mechanism of defence.
- Author
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Bomstein Y, Ophir R, Harshemes H, and Ben-Efraim S
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- Animals, Antibody Formation drug effects, Cell Line, Cells, Cultured, Culture Media, Immunologic Factors isolation & purification, Immunologic Factors pharmacology, Immunosuppressive Agents isolation & purification, Immunosuppressive Agents pharmacology, Lymphocyte Activation, Lymphocyte Culture Test, Mixed, Lymphocytes drug effects, Male, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Spleen immunology, Tumor Cells, Cultured, Immunologic Factors metabolism, Immunosuppressive Agents metabolism, Lymphocytes immunology, Plasmacytoma immunology
- Abstract
Supernatants were collected from suspensions of MOPC-315 tumor cells harvested from ascitic tumors and kept for 24 hours in culture medium and from cultures of an MOPC-315 tumor-cell kept for a long period of time in vitro. The MOPC-315 supernatants were tested for immunosuppression of mitogenic stimulation of BALB/c spleen cells by ConA or LPS, of allogeneic response of effector BALB/c spleen cells against target C57BL spleen cells, of generation of antibody response against SRBC and of induction of LAK activity. The immunosuppression was marked in all the test systems, was not related to secretion of either C-type particles or of anti-TNP antibodies and was also induced by MOPC-315 tumor cells kept in serum-free medium. It is suggested that release of immunosuppressive factor(s) by MOPC-315 tumor cells might play a role in the mechanism(s) of defence of the tumor against the host.
- Published
- 1993
25. The human lymphokine leukoregulin induces cell resistance to complement-mediated lysis.
- Author
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Fishelson Z, Shlanger S, Bomstein Y, and Evans CH
- Subjects
- Antibodies, Neoplasm immunology, Calcium physiology, Cell Survival drug effects, Complement Membrane Attack Complex immunology, Humans, Killer Cells, Natural immunology, Leukemia, Erythroblastic, Acute pathology, Protein Kinase Inhibitors, Protein Synthesis Inhibitors pharmacology, Tumor Cells, Cultured drug effects, Complement System Proteins immunology, Cytotoxicity, Immunologic drug effects, Lymphokines pharmacology
- Abstract
Leukoregulin (LR) is a lymphokine secreted by human natural killer (NK) cells. Its effect on the susceptibility of K562 human erythroleukemic cells to lysis by antibody and complement was examined. As reported here, treatment of K562 cells with LR for 60 min at 37 degrees C confers on them resistance to complement damage. The LR-induced state of complement resistance is transient and the cells recover within 4-6 h unless a second dose of LR is added. The protective action of LR was observed using both conventional 51Cr-release and trypan blue inclusion assays. The protein synthesis inhibitors puromycin and cycloheximide and the protein kinase inhibitors tamoxifen, polymyxin B and W-7, could each block this action of LR. Fewer membrane attack complexes were found, following complement activation, on LR-treated than control cells. These results suggest that LR increases the capacity of K562 cells to down-regulate complement activation or repair the complement damage, possibly by inducing synthesis of defense proteins and/or activation of protective protein kinases.
- Published
- 1992
- Full Text
- View/download PDF
26. Regulation of heme synthesis in the regenerating rat liver.
- Author
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Mamet R, Schoenfeld N, Mevasser R, Bomstein Y, Lahav M, and Atsmon A
- Subjects
- 5-Aminolevulinate Synthetase antagonists & inhibitors, 5-Aminolevulinate Synthetase metabolism, Allylisopropylacetamide pharmacology, Animals, Dicarbethoxydihydrocollidine pharmacology, Male, Rats, Rats, Inbred Strains, Heme biosynthesis, Liver Regeneration physiology
- Abstract
This investigation shows that the regulation of heme synthesis in the regenerating rat liver does not differ from the regulation in the normal liver. The heme saturation of tryptophan pyrrolase was found to be low, indicating a reduced concentration of heme in the regulatory heme pool of the regenerating rat liver. As expected, ALAS in the mitochondrial fraction was found to be elevated. It was also shown that ALAS in the regenerating rat liver can be induced by the porphyrinogenic drugs AIA and DDC and that heme reduces its activity. The decrease observed in the activity of cytosolic ALAS might be due to impaired synthesis of the enzyme but does not affect the regulation of the heme biosynthetic pathway.
- Published
- 1990
- Full Text
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27. L-Alanine: 4,5-dioxovalerate transaminase does not regulate heme synthesis in rat liver.
- Author
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Mamet R, Mevasser R, Bomstein Y, Atsmon A, and Schoenfeld N
- Subjects
- Alanine metabolism, Allylisopropylacetamide pharmacology, Aminolevulinic Acid metabolism, Animals, Chick Embryo, Dicarbethoxydihydrocollidine pharmacology, Enzyme Induction drug effects, Hemin pharmacology, Liver embryology, Male, Phenobarbital pharmacology, Porphyrins biosynthesis, Rats, Rats, Inbred Strains, Valerates metabolism, Heme biosynthesis, Liver enzymology, Transaminases metabolism
- Abstract
L-Alanine: 4,5-dioxovalerate transaminase (ADT) was determined in liver homogenates of rats treated by either inducers of porphyrin synthesis or the repressor, hemin. ADT activity was not induced by the porphyrinogenic agents nor reduced by hemin, indicating that ADT probably has no regulatory role in the heme synthesis pathway. The same conclusion was drawn from similar experiments performed in monolayers of chick embryo liver cells.
- Published
- 1990
- Full Text
- View/download PDF
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