Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Point-mutational activation of the c-Ki-ras proto-oncogene has been shown to be rare in human hepatocellular carcinoma, the most common primary liver cancer and one usually associated with chronic viral infection. To reveal the association of c-Ki-ras activation with cholangiocarcinogenesis under different etiological backgrounds, the incidence of point mutation at codons 12 and 13 of the c-Ki-ras proto-oncogene was examined in three groups of human liver cancers with differentiation to biliary epithelial cells: Group 1, cholangiocellular carcinoma in Japanese with normal livers; Group 2, cholangiocellular carcinoma in Thais who had lived in an area where the liver fluke Opisthorchis viverrini is endemic; and Group 3, combined hepatocellular-cholangiocellular carcinoma, a rare type showing features of both hepatocellular and biliary epithelial differentiation, in Japanese with chronic viral hepatitis with or without cirrhosis. The polymerase chain reaction and direct sequencing of its product were used to detect the mutation. Point mutation at codon 12 of the c-Ki-ras gene was detected in five (56%) of nine cases in Group 1. In contrast, the mutation was not detected in any of the cases in Groups 2 and 3. Therefore, point-mutational activation of c-Ki-ras did not seem to be involved in the development of primary liver cancers associated with apparent chronic irritation of liver cells or biliary epithelial cells caused by exogenous liver-fluke or viral infection. On the other hand, point-mutational activation of the c-Ki-ras proto-oncogene may be involved in cholangiocarcinogenesis in liver without preexisting liver-fluke or viral infection.
Mol Carcinog 1992
PMID:Cholangiocarcinomas in Japanese and Thai patients: difference in etiology and incidence of point mutation of the c-Ki-ras proto-oncogene. 133 66

In situ hybridization (ISH) techniques have proven to be invaluable tools for diagnostic molecular laboratories in the detection of gene expression and viral infection in cell and tissue samples. Radioactively labeled probes are still widely used for ISH because of their high sensitivity in detection. Among the non-isotopic systems only biotinylated probes for viral DNA detection found broader acceptance. Recently we introduced the digoxigenin probe labeling and detection system for ISH in our diagnostic molecular laboratory. Our experiences with digoxigenin-labeled probes are summarized in this report in the form of technical recommendations for probe choice, labeling, quantification, hybridization and detection. Several ISH protocols using RNA, DNA and oligonucleotide probes for the detection of mRNA and viral DNA are reported. Advantages, disadvantages and pitfalls of the digoxigenin system as well as comparisons with radiolabeled and other non-isotopic systems are discussed. Digoxigenin-labeled probes provide an attractive alternative to radiolabeled probes and are superior to other nonradioactive probes for ISH. Probe labeling, quantification, hybridization and detection can be performed with low biohazard risk. Working efforts and costs applying digoxigenin-labeled probes or radiolabeled probes for ISH are similar. Digoxigenin-labeled probes are stable for several months, provide an equal sensitivity in detection and a higher degree of cellular resolution than radiolabeled probes. The turnaround time of procedures is short and results of diagnostic ISH can be obtained much quicker than using radiolabeled probes.
Diagn Mol Pathol 1992 Jun
PMID:Digoxigenin as an alternative probe labeling for in situ hybridization. 134 60

The study of low-copy viral or genomic DNA sequences by in situ hybridization (ISH) is often limited by sensitivity. Using the polymerase chain reaction (PCR) for the amplification of target DNA sequences in fixed cells [in situ PCR] (ISPCR) before ISH, we have been able to greatly improve the sensitivity of ISH. Viral DNA present in low copy number, single-copy genes, as well as immunoglobulin gene rearrangements (VH3 family genes), were successfully amplified in cells in suspension or on glass slides (cytospins). Single primer pairs were used in the in situ amplification step and 35S- or digoxigenin-11-dUTP-labeled region specific oligonucleotide probes were used for detection of amplificants by ISH. Artifacts, presumably resulting from leakage of in situ amplificants out of cells, may be a significant problem in selected instances. By optimal fixation and permeabilization of cells, limiting PCR cycle number, amplification of long DNA sequences, and/or incorporation of biotinylated dNTPs to produce bulkier amplificants together with washing of cells after ISPCR, diffusion artifacts were significantly reduced. Probe hybridization to single-stranded long PCR fragments or messenger RNA were excluded as a source for false-positive ISPCR results. The techniques reported dramatically increase the sensitivity of ISH in the detection of low-copy viral infection as well as in the study of gene rearrangements, and provide unique opportunities to study chromosomal translocations and point mutations at the cellular level.
Diagn Mol Pathol 1992 Jun
PMID:In situ polymerase chain reaction detection of viral DNA, single-copy genes, and gene rearrangements in cell suspensions and cytospins. 134 61

The low copy number of human immunodeficiency virus 1 (HIV-1) DNA infected cells precludes routine detection by in situ hybridization. The inability to detect cells latently infected by HIV-1 makes difficult the study of factors that induce viral transcription, an essential factor in the development of the acquired immune deficiency syndrome (AIDS). A sensitive and rapid technique to detect HIV-1 DNA could be used as a diagnostic test for AIDS and to differentiate latent versus active viral infection. We describe a 3-h technique whereby HIV-1 DNA is amplified by hot start polymerase chain reaction (PCR) and detected directly in infected cells. The specificity of the assay was demonstrated by double labeling the positive cells with CD4. Using a CR10 HIV-1-infected cell line, the 90% of cells that were HIV-1 DNA positive could be distinguished from the 10% that were actively expressing HIV-1 RNA. The PCR in situ technique should allow for the direct localization of DNA sequences in cells that would otherwise be undetectable by conventional in situ analysis.
Diagn Mol Pathol 1992 Jun
PMID:Rapid in situ detection of PCR-amplified HIV-1 DNA. 136 73

A cDNA library from freshly isolated mesophyll protoplasts of Nicotiana sylvestris was differentially screened using cDNAs from leaves, leaf strips submitted to the same stress as protoplasts during the isolation procedure, and cell suspension cultures. One of the selected clones (6P2) was found to encode a putative polypeptide highly homologous to previously characterized 3-hydroxy-3-methylglutaryl coenzyme A reductases. The C-terminal region of the polypeptide was highly conserved whereas its N-terminal region including the trans-membrane domains and the linker was more variable. Apart from protoplasts, the 6P2 gene was found to be expressed in apexes, anthers, roots, and in stressed leaf strips after 24 h of culture, during the hypersensitive reaction to viral infection and after HgCl2 treatment. This pattern of expression is consistent with a role in plant defence mechanisms.
Plant Mol Biol 1992 Oct
PMID:Isolation and characterization of a cDNA encoding a 3-hydroxy-3-methylglutaryl coenzyme A reductase from Nicotiana sylvestris. 139 79

The survival of a host challenged by viral infection depends on many factors. Some are specific, such as antiviral T-cell and B-cell responses. Others are nonspecific, such as intrinsic cellular resistance, macrophage activation, and activation of humoral protective mechanisms (e.g., complement, coagulation, etc.). Cytokines are important mediators and regulators of both types of host response. Furthermore, orchestration of specific humoral and cellular immune responses requires the participation of many cytokines. Details of the complex and overlapping roles that cytokines play in specific immune responses is beyond the scope of this review. Instead, this review will focus on the nonspecific antiviral effects of cytokines.
Mol Biother 1992 Jun
PMID:Modulation of viral infections by cytokines. 151

A double-stranded RNA (dsRNA)-specific modification activity from Xenopus oocytes and human cells dsRNA modifier) converts adenosine residues present in dsRNA to inosines. The function of the dsRNA modifier is unknown, although it has been suggested that it may be part of the cellular antiviral response. We investigated the relationship between the activity of the dsRNA modifier, viral infection, and the antiviral response in human cells induced by poly(rI)-poly(rC) [poly(I.C)] treatment. We found, unexpectedly, that treatment of HeLa cells with poly(I.C) or other dsRNA molecules resulted in the dramatic inhibition of the dsRNA modifier. Mixing experiments, reconstruction experiments, and pretreatment of extracts with RNases indicated that inhibition of the dsRNA modifier did not result from the continued presence of a soluble inhibitor such as dsRNA) in the in vitro modification reactions. Treatment of cells with cyclohexamide or dactinomycin simultaneously with the poly(I.C) demonstrated that in vivo inhibition of the dsRNA modifier did not require new transcription or translation. The dsRNA modification activity was also substantially inhibited in cells infected with poliovirus and was slightly inhibited in cells infected with adenovirus. The inhibition of the dsRNA modifier during the antiviral state is thus not consistent with an antiviral function, and instead suggests another cellular function for dsRNA modification.
Mol Cell Biol 1991 Jul
PMID:Regulation of a double-stranded RNA modification activity in human cells. 164 94

Eight recombinant clones were obtained by insertion of BamHI fragments of herpes simplex type I viral DNA into a vector plasmid pUC19o. Of the obtained clones 5 were found to hybridize with herpes simplex type I and 2 viral DNA while 3 clones revealed a positive reaction with the Vero cells DNA. A constructed DNA-probe possessing the highest level of activity was selected for further studies. The probe is a BamHI fragment of herpes simplex type I viral DNA labelled with 32P dTTP. Probe sensitivity in blot hybridization is 10 pg for identification of type I viral DNA and 50 pg for type 2 viral DNA. The DNAs of cytomegalovirus and herpes zoster virus do not show positive signals with the probe. The increased sensitivity of the used dot hybridization as compared with biological or IEA antigen identification of the virus was confirmed with the clinical material from 59 patients with the different clinical manifestations of the herpes viral infection.
Mol Gen Mikrobiol Virusol 1991 Oct
PMID:[Detection of herpes simplex virus by DNA-DNA hybridization method]. 166 48

In Japan, histiocytic necrotizing lymphadenitis (Kikuchi's disease) is a relatively common reactive lesion affecting lymph nodes, but the histogenesis and pathogenesis of the disease have not been clarified. Alpha-interferon has a role in the body's defense against viral infections. Using a polyclonal antibody to human alpha-interferon, we found numerous cells, mainly histiocytes, containing alpha-interferon in affected foci in the lymph nodes from 24 patients with Kikuchi's disease. Tubuloreticular structures, thought by some authors to be associated with the production of interferon, were detected by electron microscopy in histiocytes, activated lymphocytes and vascular endothelial cells in the affected foci. These results suggested that the formation of tubuloreticular structures is a secondary phenomenon following stimulation by alpha-interferon. Further, the activity of 2'-5' oligoadenylate synthetase, which is induced by alpha-interferon and enhanced during the early or active stage of viral infection, showed increased levels of activity in the active stage of Kikuchi's disease and decreased to normal levels in the convalescent stage 2 weeks later. These results suggested the possibility of a viral etiology for Kikuchi's disease.
Virchows Arch B Cell Pathol Incl Mol Pathol 1991
PMID:Alpha-interferon in Kikuchi's disease. 168 81

Alphaviruses, like many enveloped animal viruses, enter the cell by fusing with the cell membrane. This fusion occurs only in coated vesicles at a low pH. By using X-ray solution scattering of highly purified virus particles we have gained direct evidence that a drop in pH does not alter the structure of the virus core but does cause a significant change in the structure of the virus envelope. Thus these experiments give direct evidence to support the hypothesis that a reduction in pH causes a conformational change in the virus E protein, which enables it to promote fusion with the cell envelope and trigger virus infection.
J Mol Biol 1991 Sep 05
PMID:X-ray solution scattering of Sindbis virus. Changes in conformation induced at low pH. 192 Apr 15


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