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Biomedical subjects

A Orazi

Publications and source records attributed to A Orazi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Proliferation-induced decline of primitive hematopoietic progenitor cell activity is coupled with an increase in apoptosis of ex vivo expanded CD34+ cells.

We examined the decline in hematopoietic potential observed when human CD34+ cells are cultured in vitro by evaluating the association between proliferation history and the fate of long-term hematopoietic culture-initiating cells (LTHC-ICs) as well as the onset of programmed cell death. The membrane dye PKH2 was used to track ex vivo expanded human CD34+ cells from bone marrow, cord blood, and mobilized peripheral blood, and to identify and isolate CD34+ cells that had divided once, twice, three, or four times or more, as well as cells that had remained cytokine nonresponsive and therefore failed to proliferate. These isolated groups of cells were assayed for their hematopoietic potential, cell cycle status, and percentage of apoptotic cells. A gradual decline in the content of LTHC-ICs, as well as in their ability to initiate and sustain in vitro hematopoiesis, was found to correlate with the number of in vitro cellular divisions, such that the hematopoietic potential of CD34+ cells dividing four or more times was nearly depleted. DNA analysis revealed that cells dividing more than three times resided predominantly in G0/G1 phases of the cell cycle. In addition, the percentage of CD34+ cells undergoing apoptosis was found to increase concomitantly with the number of in vitro cellular divisions; less than 10% of cells dividing once were apoptotic, whereas more than 25% of CD34+ cells dividing four or more times underwent programmed cell death. Together, these data suggest that a proliferation-associated, and possibly activation-induced, loss of hematopoietic potential among dividing CD34+ cells may result from an increase in programmed cell death among dividing primitive hematopoietic progenitor cells.

Antigens, CD34↗
PubMed1997

The BCL-6 proto-oncogene controls germinal-centre formation and Th2-type inflammation.

Structural alterations of the promoter region of the BCL-6 proto-oncogene represent the most frequent genetic alteration associated with non-Hodgkin lymphoma, a malignancy often deriving from germinal-centre B cells. The BCL-6 gene encodes a zinc-finger transcriptional repressor normally expressed in both B cells and CD4+ T cells within germinal centres, but its precise function is unknown. We show that mice deficient in BCL-6 displayed normal B-cell, T-cell and lymphoid-organ development but have a selective defect in T-cell-dependent antibody responses. This defect included a complete lack of affinity maturation and was due to the inability of follicular B cells to proliferate and form germinal centres. In addition, BCL-6-deficient mice developed an inflammatory response in multiple organs characterized by infiltrations of eosinophils and IgE-bearing B lymphocytes typical of a Th2-mediated hyperimmune response. Thus, BCL-6 functions as a transcriptional switch that controls germinal centre formation and may also modulate specific T-cell-mediated responses. Altered expression of BCL-6 in lymphoma represents a deregulation of the pathway normally leading to B cell proliferation and germinal centre formation.

Animals↗
PubMed1997

Therapeutic leukapheresis in hyperleucocytic leukaemias: lack of correlation between degree of cytoreduction and early mortality rate.

The clinical and laboratory data of 48 leukapheresis-treated patients with hyperleucocytic leukaemia (HL) was reviewed to assess the correlation between the degree of leucoreduction and early mortality. Leukapheresis resulted in > 50% leucoreductions and postapheresis WBC counts < 100 x 10(9)/l in most patients (64.5%). Patients presenting with neurological, respiratory or renal complications had higher early mortality rates than patients without such complications, despite similar initial WBC counts and comparable leucoreductions. Thus, in these patients, more efficient leucoreduction was not associated with improved early survival.

Adolescent↗
PubMed1997

Hypoplastic myelodysplastic syndromes can be distinguished from acquired aplastic anemia by CD34 and PCNA immunostaining of bone marrow biopsy specimens.

Hypoplastic myelodysplastic syndromes (h-MDSs) are difficult to distinguish from acquired aplastic anemia (AA) because of the considerable clinical, cytologic, and histologic similarities between these two disorders. Recent studies have suggested that the bone marrow (BM) in AA is characterized by a decreased number of CD34+ cells and reduced expression of proliferating cell nuclear antigen (PCNA), features that have not been associated with MDS. To determine the potential importance of these markers in the differential diagnosis of hypoplastic BM disorders, we immunostained 50 BM biopsy specimens of cytogenetically characterized cases of AA (27) and h-MDS (23). Immunohistochemical staining for CD34 was performed with QBEND10 (Vector, Burlingame, Calif), a monoclonal antibody (MoAb) reactive in routinely processed specimens, while PCNA was assessed by the PC10 MoAb (Dako, Carpinteria, Calif) using a microwave over-based antigen retrieval technique. Bone marrow specimens of h-MDS cases showed statistically higher values of PCNA and CD34 than did those of the AA cases: mean values (+/- SD) of CD34-positive cells in h-MDS, 0.94% +/- 1.1; AA, 0.04% +/- 0.1 (P = .0002); PCNA-positive cells in h-MDS, 43.59% +/- 13.3; AA, 14.80% +/- 6.4 (P < .0001). Our study confirms that AA is characterized by low expression of PCNA in BM and reduced CD34 frequency compared with h-MDS and supports the concept of an early deficiency of stem cells in the former disorder. The results also illustrate how immunostaining permits a simple distinction of these conditions in routinely processed BM biopsy specimens.

Adult↗
PubMed1997

Posttransplantation lymphoproliferative disorders in bone marrow transplant recipients are aggressive diseases with a high incidence of adverse histologic and immunobiologic features.

Posttransplantation lymphoproliferative disorders (PT-LPDs) occurring in T-cell depleted (TCD) allogeneic bone marrow transplant recipients seem to be different from those that arise in solid organ recipients in their early development, the high incidence of extensive dissemination at presentation, and their aggressive course and high fatality rate. We report a series of 10 patients with PT-LPDs after TCD allogeneic bone marrow transplant. We studied the correlation between the morphology of the lesions; their clonality based on immunoglobulin (Ig) heavy chain gene rearrangement analysis and immunohistochemistry; their proliferative activity as measured by immunoperoxidase staining for the proliferating cell nuclear antigen (PCNA) and the presence of p53 gene product overexpression. Histologically, our cases corresponded to the two morphologic categories of polymorphic B-cell lymphoma (PBCL, seven cases) and malignant lymphoma immunoblastic (ML-IB, three cases). Ig light-chain staining showed monoclonality in a minority of the cases, whereas Ig gene rearrangement analysis by polymerase chain reaction revealed B-cell clonality in three of seven cases of PBCL and in all three cases of ML-IB. The Epstein-Barr virus (EBV) genome, the expression of EBV latent membrane protein or both were found in all 10 specimens. High proliferative activity (PCNA > or = 66%) was found in all cases, with a mean PCNA value of 56% in PBCL and 84% in ML-IB. Five specimens were p53+ (two of seven PBCL and three of three ML-IB). Two of four PBCL cases resolved with the administration of donor leukocytes. All of the remaining patients died of the PT-LPD within a short time from admission. Our results show that the PT-LPDs after TCD bone marrow transplantation are characterized by a high frequency of high-grade histologic subtypes, frequent monoclonality, high proliferative activity, frequent overexpression of p53 gene product, and poor prognosis. These characteristics observed in only a minority of cases of PT-LPDs occurring after solid organ transplantation may account for the less aggressive clinical behavior observed in those diseases.

Adult↗
PubMed1997

Protective effects of interleukin-11 in a murine model of ischemic bowel necrosis.

The present study examined the effect of interleukin-11 (IL-11) in a murine model of bowel ischemia (BI). Prophylactic IL-11 administration in BI mice (induced by occluding the superior mesenteric artery for 90 min) was associated with significantly decreased morbidity and mortality. IL-11-treated mice demonstrated rapid recovery of intestinal mucosa as evidenced by an increase in mitotic activity and suppression of apoptosis in intestinal crypt cells as well as increased peripheral platelet and leukocyte counts primarily due to an increase in peripheral lymphocyte number in BI mice. In contrast to vehicle-treated mice, which uniformly developed thrombocytopenia after ischemic injury, no IL-11-treated BI mice developed thrombocytopenia during the experimental period. These data suggest a role for IL-11 in the treatment of gastrointestinal mucosal diseases due to a wide variety of causative injuries.

Animals↗
PubMed1997

013 (CD99) positivity in hematologic proliferations correlates with TdT positivity.

The monoclonal antibody 013, which detects the cell surface glycoprotein p30/32mic2 (CD99) is a characteristic, if nonspecific, marker for peripheral neuroepithelioma and Ewing's sarcoma. 013 was first produced against a human thymus leukemia antigen and has also been found in immature terminal deoxynucleotidyl transferase (TdT)-positive T cells and in a small group of hematopoietic precursor cells in the bone marrow. 013 is reactive in lymphoblastic lymphomas and acute leukemias, as well as in a variety of other hematologic malignancies. Because the distribution of 013 positivity in hematopoietic proliferations is similar to that of TdT, we hypothesized that 013 might correlate with TdT positivity. We studied 67 lymphoblastic lymphomas and acute lymphoblastic leukemias, 6 chronic myelogenous leukemias in blast crisis, a variety of acute myeloid leukemias, 5 granulocytic sarcomas, and a spectrum of 94 diffuse lymphomas other than lymphoblastic type. With the use of heat-induced epitope retrieval and automated immunostaining, we compared the results obtained with 013 and TdT, a well-established marker of lymphoblastic lymphomas and acute lymphoblastic leukemias that can also be successfully demonstrated in tissue sections by use of a similar technique. In our study, all of the 013-positive cases were also TdT positive. 013 reacted with 44 (71%) of 62 of the TdT-positive lymphoblastic lymphomas and acute lymphoblastic leukemias cases studied. We also found 013 to be positive in one case of TdT-positive acute myeloid leukemia, in two cases of chronic myelogenous leukemia in blast crisis, and in three TdT-positive granulocytic sarcomas. 013 was negative in all of the other high-grade malignant lymphomas and in TdT-negative leukemias. With use of our technique, 013 positivity appears to be restricted to hematologic proliferations that demonstrate TdT positivity. 013 may be a helpful additional marker in the diagnosis of TdT-positive leukemias and lymphomas in conventionally processed tissue sections.

12E7 Antigen↗
PubMed1997

Leukemic meningitis complicating early stage chronic lymphocytic leukemia.

Central nervous system involvement in chronic lymphocytic leukemia is rare. We describe a patient with early stage chronic lymphocytic leukemia who developed visual loss and transient paresthesias. Lumbar puncture with cytology and flow cytometry documented leukemic meningitis, which responded to standard treatment; including cranial irradiation and intrathecal chemotherapy. We review the literature of all previously reported cases of brain or meningeal involvement by chronic lymphocytic leukemia and suggest that this complication may frequently go unrecognized.

Adult↗
PubMed1996

Prolonged administration of granulocyte colony-stimulating factor (filgrastim) to patients with Fanconi anemia: a pilot study.

This report examines the effect of filgrastim (granulocyte colony-stimulating factor, [G-CSF] in 12 patients with neutropenia [absolute neutrophil count [ANC] < 1,000/mm3]) caused by Fanconi anemia (FA). Two of 14 patients who were evaluated for study entry were ineligible because of unsuspected cytogenetic abnormalities in their bone marrow (BM). G-CSF was started at 5 micrograms/kg/d. All patients had an increase in their ANC at week 8 (mean increase = 15,664/mm3). The median ANC during therapy was 5,030/mm3. Eight of 10 patients who completed 40 weeks on study maintained an ANC > 1,500/mm3 on G-CSF given every-otherday. Four patients had an increase in their platelet count by week 8 without transfusion (maximum increase = 23,000 to 45,000/mm3); however, platelet counts fell toward baseline levels as the G-CSF dose was reduced. BM CFU-MK were increased at week 8 in three of four evaluable patients. Four patients who did not receive red blood cell transfusions had an increase in their hemoglobin level of at least 2.0 g/dL. A fifth patient had a red blood cell transfusion in week 2 and then had a similar increase in hemoglobin level without subsequent transfusion. Eight of 10 patients who completed 40 weeks of treatment showed increases in the percentage of BM CD34+ cells measured by flow cytometry. The same proportion showed increases in peripheral blood CD34+ cells. Increased BM cellularity and myeloid hyperplasia were constant findings and were associated with increased expression of the proliferating cell nuclear antigen. Adverse experiences were mild fever (1 patient) and a new BM cytogenetic abnormality at week 40 (1 patient). This study shows that prolonged administration of G-CSF exerts a stimulatory effect on the BM of FA patients and may be used to maintain a clinically adequate ANC in these patients. G-CSF has beneficial effects on multiple hematopoietic lineages in some patients and may be a good candidate for use in combination cytokine protocols for FA patients with progressive aplastic anemia. G-CSF use results in an increase in circulating CD34+ cells, a finding with important implications for future gene transfer protocols.

Adolescent↗
PubMed1996

Treatment of a human breast cancer xenograft with an adenovirus vector containing an interferon gene results in rapid regression due to viral oncolysis and gene therapy.

Treatment of a human breast cancer cell line (MDA-MB-435) in nude mice with a recombinant adenovirus containing the human interferon (IFN) consensus gene, IFN-con1 (ad5/IFN), resulted in tumor regression in 100% of the animals. Tumor regression occurred when virus was injected either within 24 hr of tumor cell implantation or with established tumors. However, regression of the tumor was also observed in controls in which either the wild-type virus or a recombinant virus containing the luciferase gene was used, although tumor growth was not completely suppressed. Tumor regression was accompanied by a decrease in p53 expression. Two other tumors, the human myelogenous leukemic cell line K562 and the hamster melanoma tumor RPMI 1846, also responded to treatment but only with ad5/IFN. In the case of K562 tumors, there was complete regression of the tumor, and tumors derived from RPMI 1846 showed partial regression. We propose that the complete regression of the breast cancer with the recombinant virus ad5/IFN was the result of two events: viral oncolysis in which tumor cells are being selectively lysed by the replication-competent virus and the enhanced effect of expression of the IFN-con1 gene. K562 and RPMI 1846 tumors regressed only as a result of IFN gene therapy. This was confirmed by in vitro analysis. Our results indicate that a combination of viral oncolysis with a virus of low pathogenicity, itself resistant to the effects of IFN and IFN gene therapy, might be a fruitful approach to the treatment of a variety of different tumors, in particular breast cancers.

Adenoviruses, Human↗
PubMed1996

Haemophilus ducreyi elicits a cutaneous infiltrate of CD4 cells during experimental human infection.

Human subjects were experimentally infected with Haemophilus ducreyi for up to 2 weeks. Bacterial suspensions were delivered into the epidermis and dermis through puncture wounds made by an allergy-testing device. Subjects developed papular lesions that evolved into pustules resembling natural disease. Some papular lesions resolved spontaneously, indicating that host responses may clear infection. Bacteria were shed intermittently from lesions, suggesting that H. ducreyi may be transmissible before ulceration. Host responses to infection consisted primarily of cutaneous infiltrate of polymorphonuclear leukocytes, Langerhans cells, macrophages, and CD4 T cells of alpha beta lineage. Expression of HLA-DR by keratinocytes was associated with the presence of interferon-gamma mRNA in the skin. There was little evidence for humoral or peripheral blood mononuclear cell responses to bacterial antigens. The cutaneous infiltrate of CD4 cells and macrophages provides a mechanism that facilitates transmission of human immunodeficiency virus by H. ducreyi.

Adult↗
PubMed1996

Pro-vs-anti-CD45.

Explore the source record for details and available documents.

Antibodies, Monoclonal↗
PubMed1996

Tumor proliferative activity is predictive of pathological stage in clinical stage A nonseminomatous testicular germ cell tumors.

PURPOSE: Traditional histopathological features have failed to predict accurately the pathological stage of clinical stage A nonseminomatous germ cell tumors of the testis. Based on pilot studies in nonconsecutive patients at our university, we evaluated nontraditional risk factors (cell cycle analysis by flow cytometry, deoxyribonucleic acid analysis by single cell cytophotometry [image analysis] and assessment of proliferative activity by immunohistochemistry) combined with histopathological features in consecutive patients with clinical stage A nonseminomatous testis cancer. MATERIALS AND METHODS: Orchiectomy specimens from 105 consecutive patients with clinical stage A nonseminomatous germ cell tumors who underwent retroperitoneal lymph node dissection (76 with pathological stage A disease and 29 with proved metastasis) were recut, histopathologically reviewed, immunohistochemically stained with proliferation markers (for example Ki-67/MIB-1), and examined by flow cytometry and image analysis. RESULTS: After multiple logistic regression analysis, the G2M+S cell cycle fraction of the aneuploid tumor stemline was the most predictive parameter of pathological stage (p = 0.0004). Using a cutoff of 41%, patients with metastasis were predicted with a sensitivity of 71%. Of 61 patients with a G2M+S value of less than 41%, 53 had pathological stage A cancer (negative predictive value 87%). A low volume of embryonal carcinoma was predominant in patients at low risk for metastasis and MIB-1 immunohistochemical staining identified 23% of patients with pathological stage A tumor who were at extremely low risk for metastatic disease. CONCLUSIONS: Assessment of tumor cell proliferation cannot classify accurately high risk patients at a clinically applicable level. However, identification of patients at low risk for metastasis by flow cytometry, immunohistochemical proliferation markers and volume of embryonal carcinoma may be possible at the 90% level. MIB-1 staining is able to classify patients at extremely low risk for metastasis. These parameters deserve further study, since identification of patients at extremely low risk for metastasis could potentially decrease overall morbidity in the management of clinical stage A nonseminomatous testis cancer.

Cell Division↗
PubMed1996

Interleukin-11 prevents apoptosis and accelerates recovery of small intestinal mucosa in mice treated with combined chemotherapy and radiation.

Previous studies have shown that acute injury to rodent small intestinal mucosa as a result of either chemotherapy or radiation is caused by a combination of high-frequency cell death caused by apoptosis, continued migration of epithelial cells from the intestinal crypts toward the villi, and absence of adequate compensatory mitotic activity in the crypt bases. Recently, we have shown that IL-11, a novel multifunctional bone marrow stromal-derived growth factor, could stimulate rapid repair of small intestinal villous structures in mice treated with combined radiation and chemotherapy by increasing the mitotic index of crypt cells. To further clarify the biological mechanism responsible for its protective action, we used a similar experimental model to evaluate whether IL-11 could reduce the high frequency of apoptosis observed after cytoablative treatment. In the present study, 78 C3H/HeJ mice received 5-fluorouracil at 150 mg/kg body weight intraperitoneal injection 3 days before 7.0-Gy total body irradiation. The animals received IL-11 250 microg/kg body weight/day divided into two equal doses or vehicle control by subcutaneous injections beginning on the same day of irradiation within 1 hour of the end of the dose. The mice killed on Days 1, 2, and 5 after cytoablative treatment were autopsied, the small intestine was processed for histologic examination, and the mitotic index and other parameters were measured, including the expression of the proliferating cell nuclear antigen and of the p53 protein. Apoptosis was detected by a nonisotopic in situ DNA end-labeling technique applied to the same histologic sections. The cytoablative treatment caused marked degenerative changes in the small intestinal mucosa, including shortening of the villi and damage to the crypt cells. The degenerative changes, which included nuclear fragmentation with formation of apoptotic bodies, increased expression of proliferating cell nuclear antigen, and strong expression of p53 was seen in mice killed on Days 1 and 2 after cytotoxic treatment. IL-11 administration resulted in a partial suppression of apoptosis, as shown by a reduced number of crypt cells stained with in situ DNA end-labeling for fragmented DNA. In addition, IL-11 treatment was associated with an increase in the frequency of mitosis and proliferating cell nuclear antigen expression in crypt cells as compared with the vehicle treated mice. Morphometric analysis of intestinal villi and crypt depth showed increased villus length and decreased crypt to villus ratio after IL-11 treatment. These results indicate that IL-11 can exert a potent effect on the recovery of the small intestinal mucosa of mice by its combined effects on proliferation and apoptosis of crypt cells. IL-11 may thus have potential clinical applications in limiting the intestinal toxicity that is associated with cytotoxic therapies.

Animals↗
PubMed1996

mdm-2 oncoprotein expression associated with deletion of the long arm of chromosome 12 in a case of mantle cell lymphoma with blastoid transformation [corrected].

We report a unique case of mantle cell lymphoma in blastoid transformation associated with deletion of the long arm of chromosome 12 and with 90 kDa mdm-2 protein overexpression. Neither the mantle cells nor their blastoid counterparts expressed p53 gene product by immunohistochemical analysis. This seems to be the first reported case of this subtype of lymphoma associated with these specific cytogenetic and molecular genetic abnormalities.

Aged↗
PubMed1996

p53 overexpression in myeloid leukemic disorders is associated with increased apoptosis of hematopoietic marrow cells and ineffective hematopoiesis.

Recent evidence has shown that p53 overexpression in leukemic cells may be a consequence of p53 gene mutation or can occur via posttranslational modification mechanisms. While mutant forms of p53 may stimulate cell proliferation and transformation, wild-type p53 may inhibit DNA synthesis and cause leukemic cells to enter apoptosis. Nine bone marrow biopsies of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) with known p53 overexpression were analyzed for evidence of apoptosis of both leukemic blasts and of background hematopoietic cells. This was quantified and compared with that seen in p53- AML and MDS and in normal control marrows. The rate of cell death due to apoptosis was measured by in situ end-labeling of fragmented DNA with the following results: mean values of apoptotic cells/mm2 of BM, p53+ AML and MDS (9 cases), 2.41 +/- 1.7; p53- AML and MDS (10 cases), 0.16 +/- 0.1; control marrows (20 samples), 0.05 +/- 0.0. Our results showed a significant association (P < 0.001) between p53 overexpression and increased apoptosis in all cases studied. The difference was entirely caused by the high rate of cell death observed in the erythroid and myeloid precursor cells of these marrows. These findings suggest that p53+ AML and MDS are a distinct group of marrow disorders characterized by a high rate of intramedullary cell death. This may explain why patients with p53+ leukemic disorders show excessive marrow sensitivity to chemotherapy with prolonged marrow suppression associated with the presence of cytogenetically abnormal blasts that display great drug resistance.

Adolescent↗