Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We reviewed six cases of rhabdomyosarcoma as a rare second primary malignancy in children with bilateral retinoblastoma after irradiation treatment. The patients comprised four females and two males (age range 1 year 4 months-7 years 11 months). Second tumors arose in the temporal muscle inside or close to the previously irradiated fields. All the children were alive and well 24-72 months after diagnosis. Microscopic examination showed proliferation of closely packed, small round cells with scanty cytoplasm, coarse nuclear chromatin, and increased mitotic activity without a myxoid background nor obvious alveolar architecture. The most characteristic feature was the presence of rosette-like structures in four tumors. Immunoreactivity for many skeletal muscle markers was evident, including desmin (six of six), muscle-specific actin (HHF35) (six of six), sarcomeric actin (six of six), myogenin (six of six), vimentin (six of six), and myoglobin (three of six). On reverse transcriptase-polymerase chain reaction examination, three second tumors lacked specific chimeric transcripts for alveolar rhabdomyosarcoma and Ewing's sarcoma. Unexpectedly, variable reactivity for neurofilament (150 kd) was identified in six of six second tumors as well as 15 of 20 sporadic primary rhabdomyosarcomas (75%) examined as controls, the result being confirmed by Western blot analysis. In addition, staining for retinoblastoma-susceptibility gene protein was negative in all second tumors, in contrast to positivity in 14 of 17 sporadic primary tumors (82%). This finding suggests that retinoblastoma-susceptibility gene abnormalities could be associated with the development of second primary rhabdomyosarcoma. We consider that knowledge of the occurrence of rhabdomyosarcoma and appropriate immunohistochemical study are helpful for avoiding a misdiagnosis of recurrent retinoblastoma or Ewing's sarcoma when encountering patients with a history of bilateral retinoblastoma who developed second small round cell neoplasms.
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PMID:Second primary rhabdomyosarcomas in patients with bilateral retinoblastoma: a clinicopathologic and immunohistochemical study. 980 27

In the rat lung, primary saccules are transformed into alveoli from postnatal Days 4 to 13, after which time there is a 20% reduction in the number of lung fibroblasts as the interstitial volume of the alveolar walls decreases. Our objective was to determine whether apoptosis is a factor in the observed decrease in the number of interstitial lung fibroblasts beyond Day 13. We used both histologic and flow cytometric assays to detect in lung fibroblasts the DNA fragmentation and condensation that are characteristic of apoptosis. In addition, we evaluated levels of bcl-2 and BAX messenger RNAs (mRNAs) using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Apoptotic cells were quantitated in glycol methacrylate-embedded sections of neonatal rat lungs using the terminal transferase dUTP-digoxygenin nick end-labeling (TUNEL) method. Although TUNEL-positive interstitial cells were observed in the lungs of rats ranging in age from 10 to 16 d, a dramatic increase in apoptotic cells was seen on Day 17. Although diminished in number, TUNEL-positive cells were still present on Day 28. Hoechst-stained apoptotic bodies were observed in isolated lung cells that were vimentin-positive and factor VIII-negative, which identified the apoptotic cells as fibroblasts as opposed to endothelial cells. Flow cytometric analysis of freshly isolated lung fibroblasts stained with Hoechst 33342 indicated a 24% increase in chromatin condensation in cells from 17-d versus 16-d rats. DNA fragmentation was also quantitated by flow cytometry in freshly isolated fibroblasts labeled with BODIPY-conjugated dUTP in the presence of terminal deoxynucleotidyl transferase. The percentage of lung fibroblasts containing fragmented DNA was 51.4 +/- 13.4 in 17-d, 36.9 +/- 8.6 in 18-d, and 13.8 +/- 5.4 in 19-d rat pups. Finally, evaluation by RT-PCR indicated that on postnatal Day 17, mRNA for bcl-2, which inhibits apoptosis, was decreased to 73.5 +/- 11.4% (P < 0.001) of Day 5 controls; whereas mRNA for BAX, which enhances apoptosis, was increased to 243.0 +/- 102.0% (P < 0.001) of Day 5 values. These results demonstrate that rat lung fibroblasts undergo apoptosis after the completion of alveolarization, and suggest that this decrease in fibroblast number plays an important role in the thinning and remodeling of the alveolar walls of the lung.
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PMID:Lung fibroblasts undergo apoptosis following alveolarization. 992 13

We investigated the expression and the subcellular localization of S100A1 and S100B, two Ca(2+)-binding proteins of the EF-hand type, in replicating myoblasts and fused myotubes. Northern blot and reverse transcriptase-polymerase chain reaction analyses revealed the presence of S100A1 mRNA and S100B mRNA respectively, in myoblasts. Immunofluorescence and immunogold electron microscopy were used to localize individual proteins in myoblasts and myotubes. In the present report we document that: (1) in replicating myoblasts S100B is localized to intracellular membranes, including Golgi membranes, vimentin intermediate filaments (IFs) and microtubule (MT) structures; (2) in the same cells S100A1 is found associated with intracellular membranes; (3) following treatment of replicating myoblasts with colchicine, a fraction of S100B remains colocalized with bundled and collapsed vimentin IFs, whereas another fraction follows the destiny of endoplasmic membranes; (4) under the same conditions S100A1, like a fraction of S100B, follows the collapse of the endoplasmic reticulum around the nucleus; and (5) in fused myotubes S100A1 is found diffusely in the cytoplasm, whereas S100B is mostly found associated with vimentin IFs. These data suggest that in the skeletal myogenic cell line used in the present study S100A1 and S100B might share binding sites on or close to intracellular membranes, but display a significant degree of target specificity with respect of IFs and MTs. The results of these analyses suggest that expression of S100B in skeletal muscle cells may be developmentally regulated and lend support to the possibility that S100B might regulate the MT and IF dynamics.
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PMID:Replicating myoblasts and fused myotubes express the calcium-regulated proteins S100A1 and S100B. 1032 76

There is a controversy regarding whether there are thyrotropin (TSH) receptors in orbital fat and eye muscle tissues that may play a role in the pathogenesis of Graves' ophthalmopathy. To elucidate whether there are TSH receptors in orbital fat and eye muscle tissues in patients with Graves' ophthalmopathy, we applied the method of in situ hybridization in orbital fat and eye muscle tissues obtained during the operation for patients with Graves' ophthalmopathy, to directly detect TSH receptor mRNA. To identify whether the cells with positive TSH receptor mRNA are fibroblasts, we also did vimentin immunoreactivity study. To further prove the transcript does have a full length of TSH receptor, the samples of total RNA preparations, extracted from orbital fat and eye muscle tissues, were used as a template for reverse transcriptase polymerase chain reaction (RT-PCR) using three primer sets to generate cDNA fragments and cloned for sequencing. The results showed that the expression of TSH receptor mRNA was demonstrated in adipocytes and fibroblasts of orbital fat, and perimysial fibroblasts within eye muscle tissues by in situ hybridization and vimentin immunoreactivity study. Also, by using the RT-PCR, cloning and sequencing, we further proved that the transcript does have a full length of TSH receptor. The present study suggested that there are TSH receptors expressed in orbital fat and eye muscle tissues.
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PMID:Demonstration of thyrotropin receptor mRNA in orbital fat and eye muscle tissues from patients with Graves' ophthalmopathy by in situ hybridization. 1034 63

Malignant rhabdoid tumor (MRT) is a rare and extremely aggressive malignant tumor in childhood. In this study, an MRT cell line, designated KP-MRT-NS, was established from the ascitic fluid taken from an 11-month-old girl, whose tumor had originated from the left kidney. Ultrastructural findings demonstrated the typical aggregation of whorls of intermediate filaments. Chromosome constitution was described as 46, XX, add (10)(q26)[17]/46, idem, dis (1;2)(q22;q31)[3] based on ISCN (1995) and a del (22)(q11.2) was not found in this cell line. The origin of MRT is controversial, various cellular origins having been proposed because of the phenotypic diversity of MRT. Therefore, in this study, to clarify the origin of MRT, the expressions of cytoplasmic proteins including smooth-muscle-specific proteins (alpha-smooth-muscle actin, basic calponin, smooth-muscle-myosin-heavy-chain isoforms of SM1 and SM2) in the primary-MRT tissue and cell line were analyzed. In the primary-tumor tissue, the expressions of neurofilament, vimentin and alpha-smooth-muscle actin were demonstrated by indirect immunofluorescence. In the KP-MRT-NS cell line, the expression of neurofilament, alpha-smooth-muscle actin, basic calponin and smooth-muscle-myosin heavy chain of SM1 and SM2 isoforms was revealed by immunofluorescence, Western blot and/or reverse transcriptase-polymerase chain reaction (RT-PCR). MyoD1 mRNA, determined as a skeletal-muscle-cell lineage marker, was not expressed in the primary-tumor tissue or in the KP-MRT-NS cell line. According to our findings, the MRT cells are of both neural and smooth-muscle cell phenotypes, and support the neural-crest origin of MRT.
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PMID:Malignant rhabdoid-tumor cell line showing neural and smooth-muscle-cell phenotypes. 1041 65

We describe an autopsy case of primary hepatic leiomyosarcoma in a 68-year-old man with hepatitis C virus-related liver cirrhosis. The patient, who had a history of acute hepatitis 20 years previously, died of a ruptured hepatic tumor. At autopsy, a well-circumscribed 14 x 16 x 15 cm tumor replaced the medial site of the right hepatic lobe with multiple intrahepatic and distant metastases. Histologically the tumor, which had extensive central necrosis, consisted predominantly of well or moderately differentiated spindle-shaped cells, which were positive for smooth muscle actin and vimentin on immunohistochemical staining. In addition, clusters of markedly atypical cells and myxoid change of the matrix were discretely found in the focal and small areas of the tumor. These findings indicated that many sections were necessary for the histologically accurate estimation of primary hepatic smooth muscle tumor. The histological examination of a non-tumorous lesion showed liver cirrhosis. Hepatitis C virus was detected in the cytoplasm of cirrhotic hepatocytes by immunohistochemistry and reverse transcriptase-polymerase chain reaction, but not in the tumor cells. This suggested that the virus was not directly involved in the development of primary hepatic leiomyosarcoma.
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PMID:Primary hepatic leiomyosarcoma in a patient with hepatitis C virus-related liver cirrhosis. 1069 76

We report 15 primary renal neoplasms with morphologic, immunohistochemical, and molecular features identical to those of synovial sarcoma. These tumors form a distinct subset of the entity previously designated as embryonal sarcoma of the kidney. Most were diagnosed between the ages of 20 and 50 years. On gross examination, tumors are large, partially necrotic, and usually contain smooth-walled cysts. Microscopically, tumors are characterized by mitotically active, monomorphic plump spindle cells with indistinct cell borders growing in short, intersecting fascicles. Grossly identified cysts are lined by mitotically inactive polygonal eosinophilic cells with apically oriented nuclei ("hobnailed epithelium"). The spindle cells are immunoreactive for vimentin, often immunoreactive for EMA, but typically non-immunoreactive for desmin, actin, S100, or cytokeratins, whereas the cyst epithelium is cytokeratin-positive. These findings are consistent with monophasic, spindled synovial sarcoma encircling dilated native renal collecting ducts. The presence of an SYT-SSX gene fusion resulting from the t(X;18) characteristic of synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in three of three tumors in which adequate RNA could be obtained from paraffin blocks. An additional case demonstrated the characteristic t(X; 18) translocation on cytogenetic analysis, but adequate material to perform molecular studies was not available in this case or the remaining 11 cases. Primary renal synovial sarcoma is a distinctive clinicopathologic entity confirmed by molecular detection of SYT-SSX fusion transcripts.
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PMID:Primary renal synovial sarcoma: molecular and morphologic delineation of an entity previously included among embryonal sarcomas of the kidney. 1093 49

For the advanced study of the cell and molecular biology of middle ear mucosa, an in vitro cell culture system is required. Although middle ear epithelial cells have been cultured from various species of laboratory animal, there have been no reports concerning a serial subculture system of human middle ear epithelial cells. In this paper, we describe the establishment of a primary culture system of human middle ear epithelial cells using a serum-free conditioned medium and the characterization of these cells by the expression of phenotypic characteristics of epithelial cells and mucin genes. Cultured cells were anchorage-dependent in terms of growth and showed a polygonal cobblestone-like appearance: desmosomes in the cell junction were observed by electron microscopy. In the immunocytochemical study, cytokeratin (epithelial cell marker) was expressed in all cultured cells. but von Willebrand factor (endothelial cell marker) was not. Unexpectedly, vimentin (fibroblast marker) was locally expressed, and a double stain showed the co-expression of both cytokeratin and vimentin in the same cell. The products of reverse transcriptase polymerase chain reaction from cultured cells yielded distinct bands compatible with the expected sizes of the MUC1, MUC2, MUC5AC and MUC5B genes. This culture system will allow us to prepare the cell line and to perform advanced studies of human middle ear mucosal biology.
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PMID:Mucin gene expression in cultured human middle ear epithelial cells. 1120 May 87

The long-term maintenance of human islets in culture has remained a challenge. Despite advancements in culture techniques, human islets proved to have a short life span in vitro. For the first time, we have succeeded in maintaining human islets in a defined culture medium for more than 12 months. Freshly isolated islets from a 38-year-old donor were cultured in M3:5 medium and placed on a rocker for 14 days to remove contaminated exocrine and mesenchymal cells which attached to the bottom. The floating islets were purified by daily hand-picking and transfer into fresh medium. After 14 days, purified islets were allowed to attach to the bottom of the flasks and to expand. At various time points, islets were examined immunohistochemically and electron microscopically, and the secretion of islet hormones and their mRNA were determined by radioimmunoassay and reverse transcriptase polymerase chain reaction, respectively. Within seven days of culture, ductular and acinar cells developed within the initially normal islets. With time, exocrine cell types expanded while the number of the endocrine cells and their secretion decreased. At day 60, only a few endocrine cells were identifiable, whereas most of the cells appeared undifferentiated and expressed cytokeratin 7 and 19, neuron specific enolase, tomato lectin, phaseolus leucoagglutinin, laminin, and vimentin. After 60 days, the culture consisted entirely of undifferentiated cells which could be maintained in culture for 270 days before they became senescent. This is the first report on the long-term maintenance of human islet cells in culture and allows an insight into the complex process of endocrine cell differentiation.
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PMID:Maintenance of human islets in long-term culture. 1126 43

Molecular analysis of microdissected tissue samples is used for analyzing tissue heterogeneity of histological specimens. We have developed a rapid one-step microdissection technique, which was applied for the selective procurement of tissue areas down to a minimum of 10 cell profiles. The special features of our microdissection system consist of an ultrasonically oscillating needle and a piezo-driven micropipette. The validity of this technique is demonstrated in human lung large-cell carcinoma by real-time quantitative reverse transcriptase-polymerase chain reaction assays of vimentin, cyclin D1, and carcinoembryonic antigen after linear RNA amplification. mRNA expression values of microdissected samples scattered around those of bulk tumor tissue and showed differential mRNA expression between samples of tumor parenchyma and supportive stromal cells for vimentin and carcinoembryonic antigen as confirmed by immunohistochemistry. In conclusion, this procedure requires simple equipment, is easily performed, and delivers microdissected tissue samples of oligocellular clusters suitable for further molecular analysis.
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PMID:A new method for histological microdissection utilizing an ultrasonically oscillating needle: demonstrated by differential mRNA expression in human lung carcinoma tissue. 1139 75


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