Search PubMed⌕ Search

Biomedical subjects

M A Shipp

Publications and source records attributed to M A Shipp.

At least 37 records · Page 2Linked to original sources
PubMed1995

Analysis of the human CD10/neutral endopeptidase 24.11 promoter region: two separate regulatory elements.

The cell surface zinc metalloproteinase CD10/neutral endopeptidase 24.11 (NEP) is expressed on normal and malignant lymphoid progenitors, granulocytes, and a variety of epithelial cells. To further define the tissue-specific and developmentally related expression of CD10/NEP, we have characterized two separate regulatory regions that control the transcription of 5' alternatively spliced CD10/NEP transcripts. These type 1 and 2 CD10/NEP regulatory regions are both characterized by the presence of multiple transcription initiation sites and the absence of classic TATA boxes and consensus initiator elements. The purine-rich type 1 regulatory region, which includes 5' UTR exon 1 sequence, is characterized by multiple putative PU.1 binding sites and consensus ets-binding motifs. In marked contrast, the GC-rich type 2 regulatory region contains multiple putative Sp1 binding sites, a potential consensus retinoblastoma control element (RCE), and an inverted CCAAT box. In the majority of tissues examined to date, type 2 CD10/NEP transcripts were more abundant; the abundance of type 1 transcripts was more variable, with the highest type 1 levels in fetal thymus and certain lymphoblastic leukemia cell lines.

Base Sequence↗
PubMed1995

Inflammatory effector mechanisms in asthma.

Each of these effector systems has the capacity to initiate airway obstruction or alter airway responsiveness in asthma. It is likely that they act in concert in certain asthmatic settings. Further basic and applied research will define their relative roles in asthma.

Arachidonate 5-Lipoxygenase↗
PubMed1995

High-dose CHOP as initial therapy for patients with poor-prognosis aggressive non-Hodgkin's lymphoma: a dose-finding pilot study.

PURPOSE: To purpose of this study was to develop a more effective approach to the treatment of patients with poor-prognosis aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Thirty newly diagnosed patients with bulky (> or = 10 cm) advanced-stage aggressive NHL were enrolled onto a pilot study. The study was designed to determine the maximum-tolerated dosages (MTD) of cyclophosphamide and doxorubicin that could be used in a high-dose cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen with granulocyte colony-stimulating factor (G-CSF) support and to assess preliminarily the efficacy of the regimen. RESULTS: In the initial dose-finding portion of the study, cumulative thrombocytopenia was the dose-limiting toxicity. At the MTD, the regimen included four 21-day cycles of cyclophosphamide 4 gm/m2, doxorubicin 70 mg/m2, vincristine 2 mg, and prednisone 100 mg for 5 days with mesna and G-CSF support. At the MTD, 65% of treatment cycles were complicated by febrile neutropenia, 84% of patients received at least one platelet transfusion for platelet counts less than 20,000/microL, and there was one treatment-related death. Nineteen of 22 (86%; 90% confidence interval [CI], 68 to 96) patients treated at the MTD achieved an initial complete response (CR), and 79% (90% CI, 58 to 92) of the complete responders and 69% of all patients remain progression-free with 20 months median follow-up. CONCLUSION: The high-dose CHOP regimen may be an effective alternative for patients with poor-prognosis aggressive NHL.

Adult↗
PubMed1994

Prognostic factors in aggressive non-Hodgkin's lymphoma: who has "high-risk" disease?

As the above-mentioned cellular and molecular parameters and newly identified biologic features are evaluated in larger numbers of patients with aggressive NHL, the biologic heterogeneity of this disease will be better appreciated. With a more complete understanding of the disease, it is likely that we will substitute biologic variables for clinical surrogate features in our prognostic factor models and target these biologic variables for therapy in specific subsets of patients. In the meantime, widely accepted clinical models such as the International Index and the age-adjusted index will aid in the identification of specific patient risk groups and the ongoing comparison of different therapeutic approaches. Early restaging with sensitive techniques like Ga-67 citrate scans may also identify patients with suboptimal responses to induction therapy at timepoints when additional therapeutic alternatives may be most effective.

Adult↗
PubMed1994

CD10/NEP in non-small cell lung carcinomas. Relationship to cellular proliferation.

The cell surface metalloproteinase CD10/neutral endopeptidase 24.11 (NEP) hydrolyzes a variety of peptide substrates and reduces cellular responses to specific peptide hormones. Because CD10/NEP modulates peptide-mediated proliferation of small cell carcinomas of the lung (SCLC) and normal fetal bronchial epithelium, we evaluated the enzyme's expression in non-small cell lung carcinomas (NSCLC). Bronchoalveolar and large cell carcinoma cell lines had low levels of CD10/NEP expression whereas squamous, adenosquamous, and adenocarcinoma cell lines had higher and more variable levels of the cell surface enzyme. Regional variations in CD10/NEP immunostaining in primary NSCLC specimens prompted us to correlate CD10/NEP expression with cell growth. In primary carcinomas of the lung, clonal NSCLC cell lines and SV40-transformed fetal airway epithelium, subsets of cells expressed primarily CD10/NEP or the proliferating cell nuclear antigen (PCNA). Cultured airway epithelial cells had the lowest levels of CD10/NEP expression when the highest percentage of cells were actively dividing; in addition, these cells grew more rapidly when cell surface CD10/NEP was inhibited. NSCLC cell lines had receptors for a variety of mitogenic peptides known to be CD10/NEP substrates, underscoring the functional significance of growth-related variability in CD10/NEP expression.

Base Sequence↗
PubMed1993

Alternatively spliced CD44 transcripts in diffuse large-cell lymphomas: characterization and comparison with normal activated B cells and epithelial malignancies.

CD44 exists in a variety of alternatively spliced isoforms that include variable numbers of additional exons from the membrane proximal domain (exons 6-14). Lymphocytes express high levels of a "hematopoietic" isoform (CD44H) with no additional variable exons. CD44H binds lymphocytes to postcapillary venules and promotes lymphocyte extravasation into nodal areas. Epithelial carcinomas also express CD44 variants, including exon 10-containing isoforms associated with metastasis in a rat model. An exon 10-containing CD44 isoform is also transiently expressed by normal activated lymphocytes, suggesting that the protein may function in the trafficking of both normal lymphocytes and metastatic tumors. To identify the specific CD44 transcripts in tumors from patients with primary nodal, extranodal, and disseminated large-cell lymphomas (LCLs) and compare them with CD44 mRNAs in normal Ig-activated splenic B cells and epithelial cells, we used a semiquantitative RNA-based polymerase chain reaction. Specific CD44 variants were identified by size, hybridization with exon-specific probes, and sequence analysis. In comparison to primary nodal LCLs, extranodal and disseminated LCLs had increased levels of CD44H and additional isoforms, including a directly spliced (exon 5-->exon 10-->exon 15) exon 10-containing CD44 variant. The CD44 transcripts in extranodal and advanced-stage LCLs were similar to those in normal Ig-activated splenic B cells, whereas epithelial malignancies contained decreased CD44H and increased amounts of larger CD44 variants with additional exons from the membrane proximal domain. The regulated expression of specific CD44 variants is likely to influence the trafficking of lymphoid and epithelial malignancies.

Alternative Splicing↗
PubMed1993

Inhibition of CD10/neutral endopeptidase 24.11 promotes B-cell reconstitution and maturation in vivo.

The common acute lymphoblastic leukemia antigen [(CALLA) CD10, neutral endopeptidase 24.11 (NEP)] is a cell-surface zinc metalloprotease expressed by a subpopulation of early murine B-lymphoid progenitors and by bone marrow stromal cells that support the earliest stages of B lymphopoiesis. In previous in vitro studies in which uncommitted murine hematopoietic progenitors plated on a stromal cell layer differentiate into immature B cells, the inhibition of CD10/NEP increased early lymphoid colony numbers. To further characterize CD10/NEP function during lymphoid ontogeny in vivo, we utilized a Ly5 congenic mouse model in which the lymphoid differentiation of uncommitted hematopoietic progenitors from Ly5.1 donors was followed in sublethally irradiated Ly5.2 recipients treated with a specific long-acting CD10/NEP inhibitor (N-[L-(1-carboxy-2-phenyl)ethyl]-L-phenylalanyl-beta- alanine (SCH32615)). The expression of Ly5.1, B220, and surface IgM (sIgM) was utilized to characterize donor-derived hematopoietic cells (Ly5.1+), B lymphocytes (B220+), and mature B cells (B220+ sIgM+) from the lymphoid organs of recipient animals treated with SCH32615 or vehicle alone. SCH32615-treated animals had higher percentages of Ly5.1+ donor splenocytes than animals treated with vehicle alone (16.9% vs. 10.4%, 63% increase, P = 0.013). Animals treated with the CD10/NEP inhibitor also had relatively more Ly5.1+ splenic B (B220+) cells than vehicle-treated animals (14.4% vs. 8.2%, 75% increase, P = 0.018). To more specifically characterize the effects of CD10/NEP inhibition on B-cell differentiation, Ly5.1+ splenocytes from animals treated with SCH32615 or vehicle alone were analyzed for coexpression of B220 and sIgM. Animals treated with the CD10/NEP inhibitor had a significantly higher percentage of mature donor B cells (Ly5.1+ B220+ sIgM+, 10.2% vs. 5.2%, 90% increase, P = 0.006) and a more modest relative increase in immature donor B cells (Ly5.1+ B220+ sIgM-, 4.7% vs. 3.4%, 38% increase, P = not significant). Taken together, these results suggest that CD10/NEP inhibition promotes the reconstitution and maturation of splenic B cells. Therefore, CD10/NEP may function to regulate B-cell ontogeny in vivo by hydrolyzing a peptide substrate that stimulates B-cell proliferation and/or differentiation.

Animals↗
PubMed1993

CD10/neutral endopeptidase 24.11 regulates fetal lung growth and maturation in utero by potentiating endogenous bombesin-like peptides.

Bombesin-like peptides (BLPs) are mitogens for bronchial epithelial cells and small cell lung carcinomas, and increase fetal lung growth and maturation in utero and in organ cultures. BLPs are hydrolyzed by the enzyme CD10/neutral endopeptidase 24.11 (CD10/NEP) which is expressed in bronchial epithelium and functions to inhibit BLP-mediated growth of small cell lung carcinomas. To determine whether CD10/NEP regulates peptide-mediated lung development, we administered a specific CD10/NEP inhibitor, SCH32615, to fetal mice in utero from gestational days e15-17. Fetal lung tissues were evaluated on e18 for: (a) growth using [3H]thymidine incorporation into nuclear DNA; and (b) maturation using: [3H]-choline incorporation into surfactant phospholipids, electron microscopy for type II pneumocytes, and Northern blot analyses for surfactant apoproteins A, B, and C. Inhibition of CD10/NEP stimulated [3H]thymidine incorporation into DNA (70% above baseline, P < 0.005), [3H]choline incorporation into surfactant phospholipids (38% above baseline, P < 0.005), increased numbers of type II pneumocytes (36% above baseline, P = 0.07), and fivefold higher surfactant protein A transcripts (P < 0.05). CD10/NEP-mediated effects were completely blocked by the specific bombesin receptor antagonist, [D-Phe12, Leu14]bombesin. These observations suggest that CD10/NEP regulates fetal lung growth and maturation mediated by endogenous BLPs.

Animals↗
PubMed1993

Large-cell and immunoblastic lymphoma of the mediastinum: prognostic features and treatment outcome in 57 patients.

PURPOSE: A retrospective study was performed to define clinical characteristics and therapeutic outcome for patients with large-cell and immunoblastic lymphoma of the mediastinum. PATIENTS AND METHODS: Fifty-seven patients who presented with primary, mediastinal large-cell and immunoblastic lymphoma were retrospectively studied to determine initial sites of disease, radiologic characteristics, treatment, outcome, and factors that have prognostic significance for progression-free and overall survival. RESULTS: Fifty-six of the 57 patients had disease that was confined to sites above the diaphragm. Bulky disease and extensive intrathoracic infiltration were common in these patients. All patients were treated with intensive chemotherapy regimens, and 44% of patients received chest irradiation. The overall 5-year survival by Kaplan-Meier estimation was 50% with a freedom-from-relapse rate of 45%. Predictors of disease relapse after chemotherapy included the presence of a pleural effusion (P = .015), a number of involved extranodal sites (P < .01), and a lactic dehydrogenase (LDH) ratio > 3.0 (LDH value/upper limit of assay; P = .04) as well as an incomplete treatment response as evidenced by residual mass on chest radiograph (P = .02) or persistent gallium 67 avidity (P = .01) after chemotherapy. Predictors of decreased survival included the presence of pleural effusion (P = .001), the number of involved extranodal sites (P = .022), and a positive posttreatment 67Ga scan (P = .027). CONCLUSION: Patients with primary mediastinal large-cell and immunoblastic lymphoma have an approximate 50% chance of surviving disease-free after initial therapy. The presence of pleural effusion at presentation was associated with an extremely poor outcome. Bulk disease per se was a negative predictive factor only in patients without pleural effusions when compared with patients who did not have bulk disease. In addition, all patients with involvement of two or more extranodal sites relapsed when treated with standard chemotherapy.

Actuarial Analysis↗
PubMed1992

Opioid receptor agonists and Ca2+ modulation in human B cell lines.

Opiates and opioid peptides have been shown to modulate lymphocyte functions; however, little attention has been given to the type of receptors or receptor signaling mechanisms that are involved. Receptor-mediated signaling via ionized free Ca2+ is an event thought to be important in the triggering of lymphocyte activities. We report use of the calcium indicator dye, indo-1, and flow cytometry to identify B lymphocyte calcium responses to physiologic concentrations of opioid peptides. The human B cell lines Nalm 6 and JY responded to the naturally occurring opioid pentapeptide methionine-enkephalin or other opiate receptor agonists with a rapid, dose-dependent rise in free cytoplasmic Ca2+. This opioid peptide effect on Ca2+ modulation was inhibited by the opiate receptor antagonist naloxone. The synthetic enkephalin analogue DAMGO with specificity for mu-type opiate receptors and the synthetic opiate receptor agonists U50,488H and U69,593 with selectivity for kappa-type sites also stimulated calcium responses when applied to the B cell lines. These studies provide evidence that human B cell lines express functional opiate receptors of the mu- and kappa-types and suggest that such receptors, coupled with Ca2+ modulation, are instrumental in the B cell response to opiates and endogenous opioid neuropeptides.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1992

CD10/NEP is expressed on Thy-1low B220+ murine B-cell progenitors and functions to regulate stromal cell-dependent lymphopoiesis.

To further characterize the function of the common acute lymphoblastic leukemia antigen (CALLA; CD10, neutral endopeptidase 24.11, NEP) in early lymphoid development, we have identified murine lymphoid progenitors expressing CD10/NEP and analyzed the effects of inhibiting the enzyme in in vitro assays of murine lymphoid differentiation. CD10/NEP transcripts and enzymatic activity were primarily restricted to the subpopulation of murine lymphoid progenitors, termed pro-B cells, which were isolated from bone marrow (BM) and modified Whitlock-Witte cultures and defined by coexpression of B220 and low levels of Thy-1. CD10/NEP transcripts and cell surface enzymatic activity were also detected in BM stromal cells known to support the development of B-lymphoid progenitors. In contrast, Abelson and H-ras transformed pre-B-cell lines were CD10/NEP- as were Thy-1-B220+ pre-B cells from BM and modified Whitlock-Witte cultures and Thy-1lowLin- (B220-Mac-1-GR-1-Ly-2/3-) uncommitted hematopoietic progenitors from BM. The expression of CD10/NEP on murine pro-B cells and BM stromal cells suggests a role for the enzyme in early B-cell ontogeny. In modified Whitlock-Witte cultures in which Thy-1lowLin- progenitors plated on BM stromal cells differentiate into Thy-1lowB220+ pro-B and Thy-1-B220+ pre-B cells, the addition of specific CD10/NEP inhibitors increased the number of lymphoid colonies at days 5 through 7 by 34% (P < .001). The results suggest that CD10/NEP participates in the regulation of the earliest stages of stromal cell-dependent B lymphopoiesis.

Animals↗
PubMed1992

Murine common acute lymphoblastic leukemia antigen (CD10 neutral endopeptidase 24.11). Molecular characterization, chromosomal localization, and modeling of the active site.

To further analyze CD10/NEP function in lymphoid and nonlymphoid cells using well characterized murine systems, we isolated the murine CD10/NEP homologue, determined its chromosomal location, and modeled the enzyme's active site. The murine CD10/NEP cDNA predicts a 750-amino acid (aa) type II integral membrane protein with 90% identity to the human CD10 sequence and 100% conservation of critical aa and functional motifs. The latter include the pentapeptide consensus sequence required for zinc binding and catalytic activity, additional aa associated with substrate binding, and the extracellular cysteines that participate in disulfide bonds required for enzymatic activity. Like its human homologue, murine CD10/NEP has multiple alternative 5'-untranslated region sequences. The gene is localized on the proximal half of murine chromosome 3. In Northern analysis, murine CD10/NEP transcripts are abundant in bone marrow stromal cells that support pre-B cell differentiation but are undetectable in representative Abelson transformed pre-B cell lines. The murine CD10/NEP active site was modeled by aligning critical conserved CD10/NEP residues with comparable residues in the active site of thermolysin, a bacterial metalloprotease with similar substrate specificity. The model predicts that the two enzymes have similar clefts that comprise the active site and permit zinc-dependent substrate interactions.

Amino Acid Sequence↗
PubMed1992

CD10/neutral endopeptidase 24.11 in developing human fetal lung. Patterns of expression and modulation of peptide-mediated proliferation.

The cell membrane-associated enzyme CD10/neutral endopeptidase 24.11 (CD10/NEP) functions in multiple organ systems to downregulate responses to peptide hormones. Recently, CD10/NEP was found to hydrolyze bombesin-like peptides (BLP), which are mitogens for normal bronchial epithelial cells and small cell lung carcinomas. Growth of BLP-responsive small cell lung carcinomas was potentiated by CD10/NEP inhibition, implicating CD10/NEP in regulation of BLP-mediated tumor growth. BLP are also likely to participate in normal lung development because high BLP levels are found in fetal lung, and bombesin induces proliferation and maturation of human fetal lung in organ cultures and murine fetal lung in utero. To explore potential roles for CD10/NEP in regulating peptide-mediated human fetal lung development, we have characterized temporal and cellular patterns of CD10/NEP expression and effects of CD10/NEP inhibition in organ cultures. Peak CD10/NEP transcript levels are identified at 11-13 wk gestation by Northern blots and localized to epithelial cells and mesenchyme of developing airways by in situ hybridization. CD10/NEP immunostaining is most intense in undifferentiated airway epithelium. In human fetal lung organ cultures, inhibition of CD10/NEP with either phosphoramidon or SCH32615 increases thymidine incorporation by 166-182% (P < 0.025). The specific BLP receptor antagonist, [Leu13-psi(CH2NH)Leu14]bombesin abolishes these effects on fetal lung growth, suggesting that CD10/NEP modulates BLP-mediated proliferation. CD10/NEP expression in the growing front of airway epithelium and the effects of CD10/NEP inhibitors in lung explants implicate the enzyme in the regulation of peptide-mediated fetal lung growth.

Cell Differentiation↗
PubMed1991

CD10/neutral endopeptidase 24.11 hydrolyzes bombesin-like peptides and regulates the growth of small cell carcinomas of the lung.

Bombesin-like peptides are essential autocrine growth factors for many small cell carcinomas (SCCas) of the lung. Herein, we demonstrate that these malignant pulmonary neuroendocrine cells express low levels of the cell surface metalloendopeptidase CD10/neutral endopeptidase 24.11 (CD10/NEP, common acute lymphoblastic leukemia antigen) and that this enzyme hydrolyzes bombesin-like peptides. The growth of bombesin-like peptide-dependent SCC as is inhibited by CD10/NEP and potentiated by CD10/NEP inhibition. The results provide evidence that CD10/NEP is involved in the regulation of tumor cell proliferation. Since SCCa of the lung occurs almost exclusively in cigarette smokers and cigarette smoke inactivates CD10/NEP, decreased cell surface CD10/NEP enzymatic activity may be causally related to the development of SCCa of the lung.

Amino Acid Sequence↗
PubMed1991

CD10 (CALLA)/neutral endopeptidase 24.11 modulates inflammatory peptide-induced changes in neutrophil morphology, migration, and adhesion proteins and is itself regulated by neutrophil activation.

The common acute lymphoblastic leukemia antigen (CALLA, CD10), which is expressed on early lymphoid progenitors and neutrophils, is the zinc metalloprotease, neutral endopeptidase 24.11 (NEP, "enkephalinase"). The CD10 cell surface enzyme is known to hydrolyze a variety of biologically active peptides including met-enkephalin, formyl-met-leu-phe (f-MLP), and substance P. These three CD10/NEP substrates induce the migration and aggregation of neutrophils, suggesting that each of the peptides can function as a mediator of neutrophil inflammatory responses. Recently, inhibition of CD10/NEP was found to reduce the concentration of metenkephalin needed to activate human and invertebrate granulocytes by several orders of magnitude. Herein we show that f-MLP and substance P induce rapid changes in neutrophil morphology, migration, and adhesion molecule expression, including upregulation of Mo1 (CD11b/CD18) and shedding of LAM-1 (also known as LECAM-1, Leu8, or TQ-1, the human homologue of murine gp100MEL14). Importantly, these coordinated changes are potentiated by inhibition of cell surface CD10/NEP enzymatic activity. Neutrophil cell surface CD10/NEP enzymatic activity is also shown to be regulated by the activation state of the cell during the time period in which the enzyme has its most pronounced effects. These results suggest that in neutrophils, CD10/NEP functions to control responsiveness to multiple inflammatory peptides.

Antigens, Differentiation↗
PubMed1991

Drug-related pulmonary toxicity in non-Hodgkin's lymphoma. Comparative results with three different treatment regimens.

Pulmonary toxicity may complicate the treatment of non-Hodgkin's lymphoma (NHL). The possible drug-related cause of pulmonary toxicity was investigated retrospectively in 207 NHL patients treated between 1981 and 1988 with three regimens containing cyclophosphamide with and without methotrexate or bleomycin: methotrexate, calcium, leucovorin, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone (m-BACOD) (n = 134); methotrexate, calcium, leucovorin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone (m-ACOD) (n = 43); or cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) (n = 30) chemotherapy. These regimens contained the same drugs and were administered in the same schedule; the regimens differed primarily in the addition of bleomycin or methotrexate. Pulmonary toxicity occurred in 24 of 134 (18%) m-BACOD-treated and in six of 43 (14%) m-ACOD-treated patients (P = 0.65). Chest radiography revealed diffuse pulmonary infiltrates in 16 (67%) and six (100%) of the m-BACOD-treated and m-ACOD-treated patients with pulmonary toxicity, respectively. None of the CHOP-treated patients had pulmonary toxicity. The clinical features of pulmonary toxicity and the amount of chemotherapy administered before it occurred did not differ in patients treated with m-BACOD or m-ACOD, although the toxicity tended to be more severe in the m-BACOD group. Open lung or transbronchial biopsies done in six (38%) of the m-BACOD-treated and three (50%) of the m-ACOD-treated patients with pulmonary infiltrates revealed nonspecific pneumonitis compatible with drug-related toxicity. In summary, these results showed that pulmonary toxicity during m-BACOD and m-ACOD therapy occurred with similar frequency and clinicopathologic features. This suggested that bleomycin was not responsible uniquely for the pulmonary toxicity in m-BACOD-treated patients. That pulmonary toxicity was not observed in patients treated with CHOP suggested that methotrexate may play an important role in the pathogenesis of the pulmonary toxicity.

Adult↗