Multiple positron-emission tomography false positives in a patient with malignant melanoma.
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
O Kocher
Publications and source records attributed to O Kocher.
Automated detection of the G20210A prothrombin mutation using the LCx microparticle enzyme immunoassay.
BACKGROUND: The prothrombin mutation, a G/A transition at position 20210 in the 3' untranslated region of the prothrombin gene, is associated with an increased risk of deep venous thrombosis and obstetrical complications. Several methods have been developed to detect the mutation; however, given the increased demand for this test in risk factor assessment, the development of simple and efficient screening methods has become necessary. METHODS: We have used a rapid, sensitive, and precise method developed by Abbott Laboratories to detect the prothrombin mutation. The method employs a polymerase chain reaction (PCR) amplification and the Abbot LCx microparticle enzyme immunoassay (MEIA) for detection. This method is able to detect and identify both homozygous and heterozygous genotypes. RESULTS: Two hundred ninety-six patients with a history of deep venous thrombosis, pulmonary embolism, preeclampsia, or cardiovascular disease and 163 control patients were included in this study. The prevalence of the mutation was 5.74% in the high-risk group and 3.06% in the control group. There was complete agreement between the results from the MEIA detection with those obtained using other detection methodologies, namely standard PCR and restriction fragment length polymorphism (RFLP) analysis. CONCLUSIONS: The MEIA detection method of the prothrombin mutation represents a simple, fast, and reliable alternative to standard methods of detection and is well suited for use in routine clinical laboratories. The results of our study confirm others' studies showing a greater incidence of G20210A prothrombin gene mutation in patients with an increased risk of venous thrombosis and pulmonary embolism as well as patients with cardiovascular disease and pregnant women with preeclampsia. It reinforces the necessity of including the screening for prothrombin mutation in populations at risk.
3' Untranslated Regions↗
Hodgkin's lymphoma of T-cell type: clonal association with a CD30+ cutaneous lymphoma.
The derivation of Reed-Sternberg cells in Hodgkin's lymphoma has been a subject of great interest. In most cases, Reed-Sternberg cells seem to be derived from germinal center B cells. In few sporadic cases, a T-cell origin has been shown. This article supports the concept of a T-cell derivation for rare cases of Hodgkin's lymphoma and provides evidence of a novel mechanism of pathogenesis from chronic inflammation in the skin.
Base Sequence↗
Differential expression of thymosin beta-10 by early passage and senescent vascular endothelium is modulated by VPF/VEGF: evidence for senescent endothelial cells in vivo at sites of atherosclerosis.
VPF/VEGF acts selectively on the vascular endothelium to enhance permeability, induce cell migration and division, and delay replicative senescence. To understand the changes in gene expression during endothelial senescence, we investigated genes that were differentially expressed in early vs. late passage (senescent) human dermal endothelial cells (HDMEC) using cDNA array hybridization. Early passage HDMEC cultured with or without VPF/VEGF overexpressed 9 and underexpressed 6 genes in comparison with their senescent counterparts. Thymosin beta-10 expression was modulated by VPF/VEGF and was strikingly down-regulated in senescent EC. The beta-thymosins are actin G-sequestering peptides that regulate actin dynamics and are overexpressed in neoplastic transformation. We have also identified senescent EC in the human aorta at sites overlying atherosclerotic plaques. These EC expressed senescence-associated neutral beta-galactosidase and, in contrast to adventitial microvessel endothelium, exhibited weak staining for thymosin beta-10. ISH performed on human malignant tumors revealed strong thymosin beta-10 expression in tumor blood vessels. This is the first report that Tbeta-10 expression is significantly reduced in senescent EC, that VPF/VEGF modulates thymosin beta-10 expression, and that EC can become senescent in vivo. The reduced expression of thymosin beta-10 may contribute to the senescent phenotype by reducing EC plasticity and thus impairing their response to migratory stimuli.
Actins↗
Cloning of DLM-1, a novel gene that is up-regulated in activated macrophages, using RNA differential display.
Tumors interact with their environment, reprogramming host cells to induce responses such as angiogenesis, inflammation, immunity and immune suppression. To understand these processes, it is important to identify and isolate new genes whose expression is induced in host tissues in response to tumors. Ascites tumors offer an attractive model for isolating such genes, because responding host peritoneal lining tissues can be cleanly separated from tumor cells growing in suspension within the peritoneal cavity. We here report the cloning by differential display of a novel gene, DLM-1, that is highly up-regulated in the peritoneal lining tissue of mice bearing MOT ascites tumors. Mouse peritoneal macrophages, stimulated by IFN-gamma or LPS, also expressed significant amounts of DLM-1. Up-regulation of DLM-1 became evident by 4h after stimulation with IFN-gamma and was not blocked by cycloheximide, suggesting the presence of IFN responding elements in its transcription regulation region. DLM-1 RNA was detected at significant levels in normal mouse lung, intestinal epithelium, liver and thymus by Northern blot analysis. In situ hybridization of MOT and HT-29 mouse subcutaneous transplanted solid tumors revealed strong DLM-1 expression in the host reactive stromal cells, but not the tumor cells. Sequence analysis of the full-length cDNA clone revealed that it encodes a protein of approx. M(r) 44330 with multiple potential protein kinase C and casein kinase II phosphorylation sites. Our data suggest that DLM-1 plays a role in such important processes as host response in neoplasia.
Amino Acid Sequence↗
Interaction between RGS7 and polycystin.
Regulators of G protein signaling (RGS) proteins accelerate the intrinsic GTPase activity of certain Galpha subunits and thereby modulate a number of G protein-dependent signaling cascades. Currently, little is known about the regulation of RGS proteins themselves. We identified a short-lived RGS protein, RGS7, that is rapidly degraded through the proteasome pathway. The degradation of RGS7 is inhibited by interaction with a C-terminal domain of polycystin, the protein encoded by PKD1, a gene involved in autosomal-dominant polycystic kidney disease. Furthermore, membranous expression of C-terminal polycystin relocalized RGS7. Our results indicate that rapid degradation and interaction with integral membrane proteins are potential means of regulating RGS proteins.
Amino Acid Sequence↗
Differential expression of frpHE: a novel human stromal protein of the secreted frizzled gene family, during the endometrial cycle and malignancy.
By using the differential display technique to identify genes that are differentially expressed in human endometrial carcinoma compared with normal endometrium, we have cloned frpHE, a novel member of the secreted frizzled gene family. By in situ hybridization, we have determined that frpHE is expressed by mesenchymal cells but not by epithelial cells. The expression of frpHE is modulated during the endometrial cycle: it is expressed in the stroma of proliferative endometrium and not significantly detectable in secretory or menstrual endometrium, suggesting that frpHE is under hormonal regulation. In addition, the expression of frpHE mRNA is markedly up-regulated in the stroma of endometrial hyperplasia and carcinoma and in the stroma of in situ and infiltrating breast carcinomas. Injection of frpHE mRNA in Xenopus embryos inhibited the Wnt-8 mediated dorsal axis duplication. These results indicate that frpHE functions as a regulator of the Wnt-frizzled signaling pathway and is involved in endometrial physiology and carcinogenesis.
Amino Acid Sequence↗
PDZK1, a novel PDZ domain-containing protein up-regulated in carcinomas and mapped to chromosome 1q21, interacts with cMOAT (MRP2), the multidrug resistance-associated protein.
We recently reported the isolation and partial characterization of two novel proteins, MAP17 and PDZK1. Using in situ hybridization, we demonstrated that MAP17 and PDZK1 mRNAs are markedly up-regulated in human carcinomas. PDZK1, originally isolated as a protein interacting with MAP17, contains four PDZ protein-interaction domains and could potentially interact with as many as four target proteins. In this paper, we confirm the overexpression of PDZK1 in human carcinomas using a specific antibody and demonstrate the localization of the PDZK1 gene to human chromosome 1q21, a region frequently altered in neoplastic conditions. Using the yeast two-hybrid system, we have also determined that PDZK1 interacts with the carboxy-terminal portion of cMOAT (MRP2), the canalicular multispecific organic anion transporter associated with multidrug resistance. This is of particular interest because proteins containing PDZ domains are involved in the clustering and signaling pathways of membrane-associated proteins, including ion channels. Therefore, the protein cluster formed by the association of cMOAT, PDZK1, and MAP17 could play an important role in the cellular mechanisms associated with multidrug resistance, and PDZK1 may represent a new target in cancer cells resistant to chemotherapeutic agents.
ATP-Binding Cassette Transporters↗
Pulmonary infiltrates, eosinophilia, and cardiomyopathy following corticosteroid withdrawal in patients with asthma receiving zafirlukast.
CONTEXT: Zafirlukast is a potent leukotriene antagonist that recently was approved for the treatment of asthma. As use of this drug increases, adverse events that occur at low frequency or in populations not studied in premarketing clinical trials may become evident. OBJECTIVE: To describe a clinical syndrome associated with zafirlukast therapy. DESIGN: Case series. PATIENTS: Eight adults (7 women and 1 man) with steroid-dependent asthma who received zafirlukast. MAIN OUTCOME MEASURES: Development of a clinical syndrome characterized by pulmonary infiltrates, cardiomyopathy, and eosinophilia following the withdrawal of corticosteroid treatment. RESULTS: The clinical syndrome developed while patients were receiving zafirlukast from 3 days to 4 months and from 3 days to 3 months after corticosteroid withdrawal. All 8 patients developed leukocytosis (range, 14.5-27.6 x 10(9)/L) with eosinophilia (range, 0.19-0.71). Six patients had fever (temperature >38.5 degrees C), 7 had muscle pain, 6 had sinusitis, and 6 had biopsy evidence of eosinophilic tissue infiltration. The clinical syndrome improved with discontinuation of zafirlukast treatment and reinitiation of corticosteroid treatment or addition of cyclophosphamide treatment. COMMENT: Development of pulmonary infiltrates, cardiomyopathy, and eosinophilia may have occurred independent of zafirlukast use or may have resulted from an allergic response to this medication. We suspect that these patients may have had a primary eosinophilic infiltrative disorder that had been clinically recognized as asthma, was quelled by steroid treatment, and was unmasked following corticosteroid withdrawal facilitated by zafirlukast.
Adult↗
H-cadherin expression inhibits in vitro invasiveness and tumor formation in vivo.
H-cadherin is a newly characterized cadherin molecule whose expression is decreased in a variety of human carcinoma cells, suggesting that it may play a role in maintaining normal cellular phenotype. To investigate how re-expression of H-cadherin could influence the malignant phenotype of human breast carcinoma cells in vivo, we transfected both control and H-cadherin expression vectors into human breast cancer cells (MDAMB435), which do not express H-cadherin constitutively. We found that invasiveness of these cells could be prevented by transfection with H-cadherin. We also compared the ability of control- and H-cadherin-transfected cells to induce subcutaneous tumors after injection into mammary fat pads of nude mice. Our results show that H-cadherin transfection produced a marked inhibition of tumor growth and modified the morphology of tumor cells: tumors from mice injected with control cells were significantly larger and contained larger cells having a higher degree of pleomorphism than those of tumors generated from carcinoma cells expressing H-cadherin. Altogether, these results indicate that H-cadherin expression antagonizes tumor growth in nude mice, presumably by enhancing cell-cell association in a tissue environment. These findings strongly suggest that H-cadherin could provide a possible target for corrective gene therapy against breast cancer.
Animals↗
Identification and partial characterization of PDZK1: a novel protein containing PDZ interaction domains.
We recently reported the isolation and partial characterization of a novel membrane-associated protein designated MAP17. In normal tissues, MAP17 was expressed only in the apical brush border of proximal tubular epithelial cells of the human adult kidney. However, MAP17 was diffusely expressed in most carcinomas originating in the kidney, colon, lung, and breast. Transfection of MAP17 into the HT29 carcinoma cell line markedly decreased cell proliferation in vitro and tumor growth in vivo, suggesting that MAP17 plays a role, either direct or indirect, in the control of cell proliferation. In an attempt to elucidate the function of MAP17, we screened a human kidney cDNA library for interacting proteins using the yeast two-hybrid system and isolated a novel protein containing PDZ protein interaction domains, which we have named PDZK1. PDZK1 is a 519-amino acid protein with a molecular weight of 63 kd; it is expressed in the kidney, pancreas, liver, gastrointestinal tract, and adrenal cortex. In situ hybridization experiments showed that the expression of PDZK1 was limited to epithelial cells. In the kidney, it colocalized with MAP17 in the brush border of proximal tubular epithelial cells. In addition, PDZK1 was overexpressed in selected tumors of epithelial origin. Although the function of PDZK1 has yet to be determined, proteins containing PDZ domains have been shown to play important roles as diverse as cell-cell interaction, cell differentiation, growth control, ion channels organization, and signal transduction. This is of particular interest because MAP17 is localized in areas either of cell-cell contact or where ion channels are localized, for example in the kidney. PDZK1 may represent the link between the cell membrane-where it interacts with MAP17-and other cytoplasmic proteins involved in biologic functions such as cell proliferation, differentiation, and ion transport.
Adult↗
Identification and partial characterization of a novel membrane-associated protein (MAP17) up-regulated in human carcinomas and modulating cell replication and tumor growth.
Using the differential display technique, we have recently reported the identification of a novel gene originally designated DD96. As determined by Northern blot and in situ hybridization, DD96 was expressed at significant levels only in a single epithelial cell population, the proximal tubular epithelial cells of the kidney. However, it was diffusely expressed in various carcinomas originating from kidney, colon, lung, and breast. Using a specific polyclonal antibody, we have not determined that the DD96 protein product is a 17-kd membrane-associated protein, which we have therefore redesignated MAP17. In normal tissues, MAP17 is expressed in significant amounts only in the kidney, where it was localized to the brush border of proximal tubular epithelial cells. However, MAP17 is expressed abundantly in carcinomas arising from kidney, colon, lung, and breast, in some cases with a membrane-associated apical glandular distribution. In tissue culture, MAP17 was localized to the cell membrane in areas of cell-cell contact, ie, the distribution of cell-function-associated proteins. Transfection of a full-length wild-type DD96 cDNA clone into a colon carcinoma cell line, HT-29, markedly decreased cell proliferation in vitro and tumor growth in vivo. Although the precise function of MAP17 remains to be determined, our findings suggest that this protein may play an important role in tumor biology.
Amino Acid Sequence↗
Identification of a novel gene, selectively up-regulated in human carcinomas, using the differential display technique.
Using the differential display technique, selecting for genes up-regulated in renal cell carcinoma compared with normal renal parenchyma, we isolated a novel gene, designated DD96. As determined by in situ and Northern blot hybridization studies, DD96 is expressed only in rare normal epithelial cell populations, such as the proximal tubular epithelial cells of the kidney. However, it is expressed diffusely in malignant epithelial cells of the wide majority of renal cell carcinomas. In addition, DD96 is overexpressed markedly in various human carcinomas originating from the colon, breast, and lung, as well as in a number of cell lines derived from tumors of these organs compared with normal epithelial cell populations. Furthermore, the expression of DD96 is induced in immortalized breast ductal epithelial cell lines compared with normal breast ductal epithelial cells, and, in vivo, in premalignant conditions, such as adenoma of the colon and ductal carcinoma in situ of the breast. Sequence analysis of a complete cDNA clone isolated from a human kidney cDNA library revealed that DD96 encodes for a protein of approximately Mr 13,500. These results suggest that DD96 may play a role in the early events associated with malignant transformation; however, its function remains to be determined.
Amino Acid Sequence↗
Overexpression of vascular permeability factor/vascular endothelial growth factor and its receptors in psoriasis.
Psoriatic skin is characterized by microvascular hyperpermeability and angioproliferation, but the mechanisms responsible are unknown. We report here that the hyperplastic epidermis of psoriatic skin expresses strikingly increased amounts of vascular permeability factor (VPF; vascular endothelial growth factor), a selective endothelial cell mitogen that enhances microvascular permeability. Moreover, two VPF receptors, kdr and flt-1, are overexpressed by papillary dermal microvascular endothelial cells. Transforming growth factor alpha (TGF-alpha), a cytokine that is also overexpressed in psoriatic epidermis, induced VPF gene expression by cultured epidermal keratinocytes. VPF secreted by TGF-alpha-stimulated keratinocytes was bioactive, as demonstrated by its mitogenic effect on dermal microvascular endothelial cells in vitro. Together, these findings suggest that TGF-alpha regulates VPF expression in psoriasis by an autocrine mechanism, leading to vascular hyperpermeability and angiogenesis. Similar mechanisms may operate in tumors and in healing skin wounds which also commonly express both VPF and TGF-alpha.
Base Sequence↗
Differential modulation of vascular cell integrin and extracellular matrix expression in vitro by TGF-beta 1 correlates with reciprocal effects on cell migration.
In vitro, BAEC and BASMC migratory phenotypes are known to be reciprocally modulated by both soluble factors and extracellular matrix proteins. In addition, integrin matrix receptors mediate endothelial and smooth muscle cell attachment and migration. To further elucidate these phenomena, we studied the effects of TGF-beta 1 on integrin expression by vascular BASMC and BAEC in tissue culture. TGF-beta 1 upregulated mRNA levels and surface pools of BASMC beta 3 integrin classes without modulating beta 1 integrin mRNA levels or expression of beta 1 integrin organization. In contrast to its effects on BASMC, TGF-beta 1 increased BAEC mRNA levels and surface expression of beta 1 and beta 3 integrins without altering their organization. Conversely, extracellular matrix components (fibronectin, laminin, and fibrinogen) organized cell surface integrins in both BASMC and BAEC without affecting the size of their cell surface pools. These data are consistent with the hypothesis that SMC and EC behavior in neointimal lesions may be modulated, in part, through a coordination of soluble factor and extracellular matrix protein regulation of integrin surface expression and organization.
Animals↗
Reversible expression of sm alpha-actin protein and sm alpha-actin mRNA in cloned cerebral endothelial cells.
The expression of smooth muscle (sm) alpha-actin was studied in cloned capillary cerebral endothelial cells of two phenotypes. Type I cells were cultured in medium containing 10% FCS, heparin and ECGS (or alpha-ECGF) and stained positive for a specific endothelial cell marker (Bandeiraea simplicifolia). Depletion of heparin and ECGS resulted in a smooth muscle-like appearance after 2-3 days. Cells of this phenotype, (type II) stained positive for the endothelial cell marker and for sm alpha-actin. In contrast to type I cells, type II cells expressed sm alpha-actin protein and mRNA as evidenced by Immunoblots and Northern blots. This phenotypic switch was shown to be reversible and so was the expression of sm alpha-actin.
Actins↗
Phenotypic features of smooth muscle cells during the evolution of experimental carotid artery intimal thickening. Biochemical and morphologic studies.
Balloon catheter denudation of rat carotid artery that results in significant medial damage is followed by marked intimal smooth muscle cell (SMC) proliferation associated with limited endothelial regrowth. In this report we demonstrate that: (a) SMC of the carotid media, preceding their intimal proliferation, develop a cytoskeletal profile and morphology consistent with a de-differentiated SMC phenotype; and (b) both medial and intimal SMC subsequently revert to a cytoskeletal profile and morphology reflecting incomplete but significant re-differentiation toward normal SMC phenotype. Specifically, early after balloon injury, SMC of the media and those that have migrated into the intima contain decreased amounts of actin, desmin, and tropomyosin and increased amounts of vimentin; moreover, beta-actin becomes the dominant actin isoform, whereas alpha-actin decreases as compared with that found in normal medial SMC. Late after balloon injury, actin is still less abundant, however, desmin, tropomyosin, and vimentin return toward normal values and both medial and intimal SMC again show a predominance of alpha-actin, although the endothelium does not regenerate over the central surface of intimal thickening in this model. The SMC surface to volume ratio significantly decreases early after balloon injury, whereas it is not significantly different late after balloon injury as compared with that of SMC of the normal carotid media. We demonstrate, furthermore that: (c) adjacent luminal SMC are interconnected by gap junctions and develop focal tight junctions, a feature not reported previously to occur in smooth muscle; these cells however do not form any well defined membrane specialization with the leading edge of endothelium, supporting the view that presence of modified SMC on the luminal surface of chronically denuded vessels is not responsible for the cessation of endothelial regrowth.
Actins↗
Modulation of gelsolin content in rat aortic smooth muscle cells during development, experimental intimal thickening and culture. An immunohistochemical and biochemical study.
Gelsolin is a Ca2+ and polyphosphoinositol-phospholipid regulated modulator of actin polymerization present in most mammalian cells and in plasma. Cytoplasmic gelsolin was first described in highly motile cells such as leukocytes, where actin polymerization is dynamic; however arterial smooth muscle cells (SMC), despite their stabilized actin bundles, express high levels of gelsolin. We have investigated gelsolin modulation in rat aortic SMC by immunohistochemistry, Western blotting and Northern hybridization using three models which are known to show modulation of actin isoform expression: development, aortic intimal thickening after experimental endothelial injury, and growth in culture. When related to the protein and mRNA content of adult aortic SMC, gelsolin is expressed about 50% in aortic SMC of five-day-old rats, 20-30% in SMC of intimal thickening 15 days after endothelial injury (when SMC are actively replicating) and in SMC growing in culture; in intimal thickening 60 days after injury (when SMC have returned to quiescence), the gelsolin content becomes similar to that of control SMC. The high level of gelsolin in smooth muscle (SM) tissues and the down regulation with proliferation and migration raises the question as to whether gelsolin in these cells has functions other than the dynamic control of actin filament length. The similar modulation patterns of gelsolin and alpha-SM actin suggest a preferential interaction between these two proteins.
Aging↗