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1.
J Virol Methods ; 300: 114369, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34813823

RESUMO

Cotton leaf curl disease (CLCuD) is caused by a complex of several whiteflies (Bemisia tabaci Genn.)-transmitted begomovirus species, Cotton leaf curl Multan virus (CLCuMuV), Cotton leaf curl Kokhran virus (CLCuKoV) and Cotton leaf curl Alabad virus (CLCuAlV) by individual of mixed infection, associated with Cotton leaf curl Multan betasatellite (CLCuMB) and several alphasatellites. The disease causes major economic losses in cotton in the Indian subcontinent. For monitoring of epidemiology and development of management strategies of CLCuD, a quick, sensitive and effective method capable of detecting all the begomovirus, betasatellite and alphasatellite components associated with CLCuD is required. With this objective, a multiplex polymerase chain reaction (mPCR) assay was developed for the simultaneous detection of these three viral components associated with CLCuD of cotton. Primers for each component were designed based on the retrieved reference sequences from the GenBank. Each pair of primers, designed for each of the respective component, was evaluated for its sensitivity and specificity in both the component-specific simplex polymerase chain reaction (sPCR) and mPCR assay. This report identified three viral component-specific pairs of primers which, in all combinations, amplified simultaneously the CP gene (780 nts) of the begomovirus, the ßC1gene (375 nts) of the betasatellite and the Rep gene (452 nts) of the alphasatellite associated with CLCuD in the mPCR assays. The amplified products specific to each component produced by these assays were identified based on their amplicon sizes, and the identities of the viral components amplified were confirmed by cloning and sequencing the amplicons obtained in the mPCR. The mPCR assay was validated using naturally CLCuD-affected cotton plants of the fields. This assay will be useful for rapid detection of CLCuD-associated begomovirus, betasatellite and alphasatellite DNA in field samples, extensive resistance screening in resistance breeding programme, and also monitoring epidemiology for detection of virus and its components when symptoms are mild or absent in the plant.


Assuntos
Begomovirus , Begomovirus/genética , DNA Viral/análise , DNA Viral/genética , Gossypium/genética , Reação em Cadeia da Polimerase Multiplex , Filogenia , Doenças das Plantas
2.
Oncogene ; 36(22): 3080-3093, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27941883

RESUMO

DEAD box RNA helicase p68 acts as a transcriptional coactivator of several oncogenic transcription factors apart from being a vital player of RNA metabolism. Signal transducer and activator of transcription 3 (Stat3) is a major oncogenic contributor of diverse cancers, including that of colon. Deciphering the mechanistic insights of coactivation of Stat3 transcriptional activity may aid in improved therapeutic strategies. Here we report for the first time a novel mechanism of alliance between p68 and Stat3 in stimulating transcriptional activity of Stat3. Interestingly, we observed that the expression of p68 and Stat3 bears strong positive correlation and significant colocalization in normal and colon carcinoma patient samples. We demonstrated that p68 directly interacts with Stat3 in HEK293 cells as well as multiple colon cancer cell lines. Additionally, p68 positively modulated both mRNA and protein expression levels of Stat3 target genes; promoter activity of Stat3 target gene Mcl-1 in multiple colon cancer cell lines. Also, p68 occupied the promoters of multiple Stat3 target genes in enhancing Stat3-dependent transcription. Moreover, the strong positive correlation between the abundance of p68 and Stat3 target genes in the same set of colon carcinoma samples further supported our observations. Enhanced expression levels of Stat3 target genes observed in primary tumors and metastatic lung nodules, generated in mice colorectal allograft model using syngeneic cells stably expressing p68, further reinforced our in vitro findings. Hence, this study unravels novel modes of p68-mediated oncogenesis through coactivation of Stat3 and enhancing Stat3 signaling.


Assuntos
Carcinogênese/genética , RNA Helicases DEAD-box/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Linhagem Celular Tumoral , RNA Helicases DEAD-box/genética , Células HCT116 , Células HEK293 , Células HT29 , Humanos , Camundongos , Fator de Transcrição STAT3/genética , Transdução de Sinais
3.
Oncogene ; 34(47): 5843-56, 2015 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-25745998

RESUMO

Increased abundance of proto-oncogene AKT and reduced expression of tumor suppressor Forkhead box O3 (FOXO3a), the downstream target of AKT, is frequent in carcinogenesis. Mechanistic insights of AKT gene regulation are limited. DEAD box RNA helicase p68 is overexpressed in various cancers and acts as a transcriptional co-activator of several transcription factors, including ß-catenin. Here, we report a novel mechanism of p68-mediated transcriptional activation of AKT, and its ensuing effect on FOXO3a, in colon carcinogenesis. Interestingly, we found that the expression of p68 and AKT exhibits strong positive correlation in normal and colon carcinoma patient samples. In addition, p68 increased both AKT messenger RNA (mRNA) and protein, enhanced AKT promoter activity in multiple colon cancer cell lines. Conversely, p68 knockdown led to reduced AKT mRNA and protein, diminished AKT promoter activity. Here, we demonstrated that p68 occupies AKT promoter with ß-catenin as well as nuclear factor-κB (NF-κB)and cooperates with these in potentiating AKT transcription. Furthermore, p68 and FOXO3a expression followed inverse correlation in the same set of colon carcinoma samples. We observed that p68 significantly reduced FOXO3a protein level in an AKT-dependent manner. Studies in primary tumors and metastatic lung nodules generated in mice colorectal allograft model, using syngeneic cells stably expressing p68, corroborated our in vitro findings. Hence, a new mechanism of oncogenesis is attributed to p68 by upregulation of AKT and consequent nuclear exclusion and degradation of tumor suppressor FOXO3a.


Assuntos
Neoplasias do Colo/metabolismo , RNA Helicases DEAD-box/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais , Animais , Linhagem Celular Tumoral , Neoplasias do Colo/patologia , Proteína Forkhead Box O3 , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Humanos , Neoplasias Pulmonares/patologia , Camundongos , Transplante de Neoplasias , Regiões Promotoras Genéticas , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-akt/metabolismo
4.
J Thromb Haemost ; 13(6): 1113-27, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25715026

RESUMO

BACKGROUND: Iron deficiency is associated with reactive thrombocytosis; however, the mechanisms driving this phenomenon remain unclear. We previously demonstrated that this occurs alongside enhanced megakaryopoiesis in iron-deficient rats, without alterations in the megakaryopoietic growth factors thrombopoietin, interleukin-6, or interleukin-11. OBJECTIVES: The aim of this study was to evaluate megakaryocyte differentiation under iron deficiency in an in vitro model and to investigate potential genes involved in this process. METHODS: Human erythroleukemia and megakaryoblastic leukemia cell lines, as well as cord-blood derived hematopoietic stem cells were cultured under iron deficiency. Cell morphology, ploidy, expression of CD41, CD61, and CD42b, and proplatelet formation were assessed in iron-deficient cultures. Polymerase chain reaction arrays were used to identify candidate genes that were verified using real-time polymerase chain reaction. Hypoxia-inducible factor 1, α subunit (HIF2α) protein expression was assessed in bone marrow sections from iron-deficient rats and vascular endothelial growth factor (VEGF)-A in culture supernatants. RESULTS AND CONCLUSIONS: Iron deficiency enhanced megakaryoid features in cell lines, increasing ploidy and initiating formation of proplatelet-like structures. In cord blood cell cultures, iron deficiency increased the percentage of cells expressing megakaryopoietic markers and enhanced proplatelet formation. HIF2α and VEGF were identified as potential pathways involved in this process. HIF2α protein expression was increased in megakaryocytes from iron-deficient rats, and VEGF-A concentration was higher in iron-deficient culture supernatants. Addition of VEGF-A to cell cultures increased percentage expression of megakaryocyte CD41. In conclusion, the data demonstrate that iron deficiency augments megakaryocytic differentiation and proplatelet formation and a potential role of HIF2α in megakaryopoiesis.


Assuntos
Anemia Ferropriva/sangue , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Megacariócitos/metabolismo , Trombocitose/sangue , Trombopoese , Anemia Ferropriva/genética , Anemia Ferropriva/patologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Linhagem Celular Tumoral , Forma Celular , Modelos Animais de Doenças , Sangue Fetal/citologia , Regulação da Expressão Gênica , Humanos , Megacariócitos/patologia , Contagem de Plaquetas , Ploidias , Ratos , Transdução de Sinais , Trombocitose/genética , Trombocitose/patologia , Fatores de Tempo , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/metabolismo
5.
Microb Ecol ; 70(1): 168-74, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25592636

RESUMO

Formation of magnetite in anaerobic sediments is thought to be enhanced by the activities of iron-reducing bacteria. Geobacter has been implicated as playing a major role, as in culture its cells are often associated with extracellular magnetite grains. We studied the bacterial community associated with magnetite grains in sediment of a freshwater pond in South Korea. Magnetite was isolated from the sediment using a magnet. The magnetite-depleted fraction of sediment was also taken for comparison. DNA was extracted from each set of samples, followed by PCR for 16S bacterial ribosomal RNA (rRNA) gene and HiSeq sequencing. The bacterial communities of the magnetite-enriched and magnetite-depleted fractions were significantly different. The enrichment of three abundant operational taxonomic units (OTUs) suggests that they may either be dependent upon the magnetite grain environment or may be playing a role in magnetite formation. The most abundant OTU in magnetite-enriched fractions was Geobacter, bolstering the case that this genus is important in magnetite formation in natural systems. Other major OTUs strongly associated with the magnetite-enriched fraction, rather than the magnetite-depleted fraction, include a Sulfuricella and a novel member of the Betaproteobacteria. The existence of distinct bacterial communities associated with particular mineral grain types may also be an example of niche separation and coexistence in sediments and soils, which cannot usually be detected due to difficulties in separating and concentrating minerals.


Assuntos
Óxido Ferroso-Férrico/análise , Sedimentos Geológicos/microbiologia , Microbiota/genética , Lagoas/microbiologia , Sequência de Bases , Primers do DNA/genética , Geobacter/genética , Sedimentos Geológicos/química , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase em Tempo Real , República da Coreia , Análise de Sequência de DNA , Especificidade da Espécie
6.
Mol Biol Cell ; 25(24): 3900-8, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25253718

RESUMO

Proper chromosome segregation is of paramount importance for proper genetic inheritance. Defects in chromosome segregation can lead to aneuploidy, which is a hallmark of cancer cells. Eukaryotic chromosome segregation is accomplished by the bipolar spindle. Additional mechanisms, such as the spindle assembly checkpoint and centromere positioning, further help to ensure complete segregation fidelity. Here we present the fission yeast csi2+. csi2p localizes to the spindle poles, where it regulates mitotic microtubule dynamics, bipolar spindle formation, and subsequent chromosome segregation. csi2 deletion (csi2Δ) results in abnormally long mitotic microtubules, high rate of transient monopolar spindles, and subsequent high rate of chromosome segregation defects. Because csi2Δ has multiple phenotypes, it enables estimates of the relative contribution of the different mechanisms to the overall chromosome segregation process. Centromere positioning, microtubule dynamics, and bipolar spindle formation can all contribute to chromosome segregation. However, the major determinant of chromosome segregation defects in fission yeast may be microtubule dynamic defects.


Assuntos
Segregação de Cromossomos , Microtúbulos/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Fuso Acromático/metabolismo , Centrômero/metabolismo , Cinética , Cinetocoros/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Microscopia Confocal , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Mitose , Mutação , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Fuso Acromático/genética , Imagem com Lapso de Tempo
7.
Genes Immun ; 12(7): 575-81, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21654841

RESUMO

Within the interleukin-10 receptor 1 (IL10R1) gene, two common variants are associated with certain diseases: single-nucleotide polymorphism 3 (SNP3), a serine-138 to glycine mutation is in linkage disequilibrium with SNP4, a glycine-330 to arginine mutation, both of which are considered loss-of-function alleles. However, the molecular consequence of G330R is unknown. We investigated possible roles of G330R on the dynamics of IL10R1 surface expression and signal transducer and activator of transduction (STAT) phosphorylation. HeLa cells expressing the respective IL10R1 haplotype were stimulated with IL-10. Significant reduction of IL10R1 surface expression was observed after ligand binding. Receptor expression remained low on continuous incubation with IL-10. In contrast, when treated with an IL-10 pulse, IL10R1 surface expression returned to its resting state within 3-9 h irrespective of the haplotype. STAT3 was rapidly phosphorylated both in cells with wild-type (WT) or variant IL10R1, and maintained phosphorylated when cells were cultured with IL-10. On IL-10 pulse, however, STAT3 phosphorylation declined rapidly in cells expressing IL10R1-G330R but not IL10R1-WT or S138G. Similar dynamics were observed with STAT1 phosphorylation at Tyr701. No differences in janus kinase 1 (JAK1) activation were observed in cells with WT or variant IL10R1. Our results indicate that IL10R1-G330R does not alter surface expression but duration of STAT phosphorylation, indicating that the position of G330 is important in stabilizing the STAT signal.


Assuntos
Subunidade alfa de Receptor de Interleucina-10/genética , Subunidade alfa de Receptor de Interleucina-10/metabolismo , Polimorfismo de Nucleotídeo Único , Fator de Transcrição STAT3/metabolismo , Pontos de Checagem do Ciclo Celular , Ativação Enzimática/genética , Regulação da Expressão Gênica , Células HeLa , Humanos , Interleucina-10/metabolismo , Janus Quinase 1/metabolismo , Ligantes , Fosforilação , Ligação Proteica , Transdução de Sinais
8.
Diagn Cytopathol ; 38(1): 47-50, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19688761

RESUMO

Calcium pyrophosphate dihydrate crystal deposition disease (CPPD) is a well-recognized inflammatory joint disorder characterized by presence of calcium pyrophosphate dihydrate crystals in intraarticular and periarticular tissue. We report here a case of a 48-year-old male who presented with painless right hand swelling. Clinical suspicion was that of malignant soft tissue tumor. Fine-needle aspiration (FNA) yielded chalky white gritty material. Microscopic examination showed large areas of basophilic calcified material, histiocytes, giant cells and characteristic rhomboid shaped crystals. At places, chondroid material was also identified, hence, diagnosis of CPPD was made. This was confirmed on histopathological examination. Tophaceous/ tumoral pseudogout is a rare form of CPPD and it is important to recognize that this form can be diagnosed in FNA cytology (FNAC) and misdiagnosis of benign or malignant cartilaginous lesions can be avoided.


Assuntos
Condrocalcinose/diagnóstico , Condrocalcinose/patologia , Mãos/patologia , Neoplasias/diagnóstico , Neoplasias/patologia , Biópsia por Agulha Fina , Condrocalcinose/diagnóstico por imagem , Diagnóstico Diferencial , Mãos/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia
9.
Oncogene ; 29(10): 1431-50, 2010 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-20023697

RESUMO

The p53-inducible gene 3 (PIG3) is originally isolated as a p53 downstream target gene, but its function remains unknown. Here, we report a role of PIG3 in the activation of DNA damage checkpoints, after UV irradiation or radiomimetic drug neocarzinostatin (NCS). We show that depletion of endogenous PIG3 sensitizes cells to DNA damage agents, and impaired DNA repair. PIG3 depletion also allows for UV- and NCS-resistant DNA synthesis and permits cells to progress into mitosis, indicating that PIG3 knockdown can suppress intra-S phase and G2/M checkpoints. PIG3-depleted cells show reduced Chk1 and Chk2 phosphorylation after DNA damage, which may directly contribute to checkpoint bypass. PIG3 exhibited diffuse nuclear staining in the majority of untreated cells and forms discrete nuclear foci in response to DNA damage. PIG3 colocalizes with gamma-H2AX and 53BP1 to sites of DNA damage after DNA damage, and binds to a gamma-H2AX. Notably, PIG3 depletion decreases the efficient induction and maintenance of H2AX phosphorylation after DNA damage. Moreover, PIG3 contributes to the recruitment of 53BP1, Mre11, Rad50 and Nbs1 to the sites of DNA break lesions in response to DNA damage. Our combined results suggest that PIG3 is a critical component of the DNA damage response pathway and has a direct role in the transmission of the DNA damage signal from damaged DNA to the intra-S and G2/M checkpoint machinery in human cells.


Assuntos
Ciclo Celular/fisiologia , Dano ao DNA , Reparo do DNA/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Western Blotting , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem , Quinase do Ponto de Checagem 2 , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/efeitos da radiação , Citometria de Fluxo , Células HCT116 , Células HeLa , Histonas/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Fosforilação/efeitos dos fármacos , Fosforilação/efeitos da radiação , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/genética , Interferência de RNA , Proteína 1 de Ligação à Proteína Supressora de Tumor p53 , Raios Ultravioleta , Zinostatina/farmacologia
10.
J Am Chem Soc ; 131(20): 6936-7, 2009 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-19419168

RESUMO

In photosynthesis, water is oxidized at a protein-bound Mn(4)Ca complex. Artificial water-oxidation catalysts that are similarly efficient and based on inexpensive and abundant materials are of great interest. Recently, assembly of a catalyst as an amorphous layer on inert cathodes by electrodeposition starting from an aqueous solution of cobalt ions and potassium phosphate has been reported. X-ray absorption spectroscopy on the cobalt catalyst film (CoCF) suggests that its central structural unit is a cluster of interconnected complete or incomplete Co(III)-oxo cubanes. Potassium ligation to Co-bridging oxygens could result in Co(3)K(mu-O)(4) cubanes, in analogy to the Mn(3)Ca(mu-O)(4) cubane motif proposed for the photosynthetic Mn complex. The similarities in function and oxidative self-assembly of CoCF and the catalytic Mn complex in photosynthesis are striking. Our study establishes a close analogy also with respect to the metal-oxo core of the catalyst.


Assuntos
Cobalto/química , Água/química , Técnicas Eletroquímicas/métodos , Análise de Fourier , Modelos Moleculares , Oxirredução , Óxidos/química , Complexo de Proteína do Fotossistema II/química , Espectrometria por Raios X/métodos
11.
J Commun Dis ; 41(3): 183-8, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22010485

RESUMO

A prospective analysis of 90 clinically diagnosed cases with acute diarrhea over a period of one year was carried out to determine the prevalence of rotavirus infection in children between 2 months to 2 years of age. Enzyme Linked Immunosorbent Assay (ELISA) and Polyacrylamide Gel Electrophoresis (PAGE) were used for detection of rotavirus from stool sample. Fourteen (15.6%) of them were found to be positive for group A rotavirus, 9 (23%) cases were between 6 months to 1 year of age. Rotavirus excretion was highest (50%) when all three symptoms (diarrhea, vomiting and fever) occurred in the same child. A planned study for surveillance of rotavirus serotypes is required from this area.


Assuntos
Diarreia/epidemiologia , Diarreia/virologia , Infecções por Rotavirus/epidemiologia , Doença Aguda , Pré-Escolar , Feminino , Hospitais/estatística & dados numéricos , Humanos , Índia/epidemiologia , Lactente , Masculino , Prevalência , Estudos Prospectivos
12.
J Cutan Pathol ; 28(4): 211-8, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11426829

RESUMO

BACKGROUND: Restrictive dermopathy is a rare autosomal recessive skin disorder that is fatal in the neonatal period. Clinical and pathologic findings are distinctive and allow for a specific diagnosis in most cases. METHODS: We present a case of an affected infant and a review of the previously reported cases in the literature. RESULTS: The infant had thick shiny skin with reduced compliance and multiple spontaneous linear splits. Additional findings included an abnormal facies with a distinctive small, round and open mouth, low set ears, small nose, widely spaced sutures, flexion contractures of the extremities, and poorly expanded lungs. The infant expired 65 h after birth. Histologic findings of the skin at autopsy included a relatively unremarkable epidermis, a flat dermal-epidermal junction (absent rete ridges), an overall thinned dermis with hypoplastic appendage structures, a dense fibrotic reticular dermis with collagen parallel to the epidermis, a sharp subcutaneous margin, and an abnormally thick layer of subcutaneous adipose tissue. Electron microscopic findings included dense dermal patches of collagen and fibroblasts with abundant endoplasmic reticulum and unusually small tonofilaments. Review of previously reported cases reveals strikingly consistent findings. CONCLUSIONS: This rare condition illustrates that abnormal cutaneous development may produce fetal hypokinesia, leading to profound effects on intrauterine growth and development. The autosomal recessive pattern of inheritance and morphologic changes of the skin and skeletal system in this disorder suggest that a structural protein or enzyme defect, perhaps of collagen metabolism, may underlie the pathogenesis.


Assuntos
Epiderme/patologia , Anormalidades da Pele/patologia , Fácies , Evolução Fatal , Fibroblastos/patologia , Fibroblastos/ultraestrutura , Humanos , Recém-Nascido , Microscopia Eletrônica
13.
J Biol Chem ; 276(26): 24286-92, 2001 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-11290737

RESUMO

We have studied the processing of O(6)-methylguanine (m6G)-containing oligonucleotides and N-methyl-N-nitrosourea (MNU)-treated DNA templates by the 3' --> 5' exonuclease of T4 DNA polymerase. In vitro biochemical analyses demonstrate that the exonuclease can remove bases opposite a defined m6G lesion. The efficiency of excision of a terminal m6G.T was similar to that of m6G.C, and both were excised as efficiently as a G.T substrate. Partitioning assays between the polymerase and exonuclease activities, performed in the presence of dNTPs, resulted in repeated incorporation and excision events opposite the m6G lesion. This idling produces dramatically less full-length product, relative to natural substrates, indicating that the 3' --> 5' exonuclease may contribute to DNA synthesis inhibition by alkylating agents. Genetic data obtained using an in vitro herpes simplex virus-thymidine kinase assay support the inefficiency of the exonuclease as a "proofreading" activity for m6G, since virtually all mutations produced by the native enzyme using MNU-treated templates were G --> A transitions. Comparison of MNU dose-response curves for exonuclease-proficient and -deficient forms of T4 polymerase reveals that the exonuclease efficiently removes 50-86% of total premutagenic alkyl mispairs. We propose that idling of exonuclease-proficient polymerases at m6G lesions during repair DNA synthesis provides the biochemical explanation for cellular cytotoxicity of methylating agents.


Assuntos
Reparo do DNA , DNA Polimerase Dirigida por DNA , Guanina/metabolismo , Proteínas Virais/fisiologia , Alquilantes/farmacologia , Pareamento Incorreto de Bases , Sequência de Bases , Exodesoxirribonucleases/fisiologia , Guanina/análogos & derivados , Metilnitrosoureia/farmacologia , Dados de Sequência Molecular , Mutagênese , Oligodesoxirribonucleotídeos/metabolismo , Ciclização de Substratos , Especificidade por Substrato , Moldes Genéticos
14.
J Cutan Pathol ; 27(10): 485-92, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11100807

RESUMO

BACKGROUND: The spectrum of cutaneous metastasis of non-hematopoietic neoplasms in the pediatric population is not well documented. We report the histologic diversity of this unusual process over a 30-year period at a tertiary care center for pediatric malignancy (St. Jude Children's Research Hospital, Memphis, TN, USA). METHODS: Of 1,971 pathology accessions which included histologic material on skin (1,604 surgical cases and 367 autopsy cases) we found 40 cases (2% of total skin accessions) coded for metastatic non-hematopoietic malignancy. RESULTS: The patients (n=34) ranged in age from 1 month to 20 years (mean=9.8 years) and had a male:female ratio of 1:1. The histologic diagnoses were as follows: rhabdomyosarcoma NOS (6 cases), embryonal rhabdomyosarcoma (4 cases), alveolar rhabdomyosarcoma (4 cases), neuroblastoma (8 cases), osteosarcoma (2 cases), choriocarcinoma (2 cases), peripheral neuroepithelioma or Ewing's sarcoma (2 cases), malignant rhabdoid tumor (1 case), paraganglioma (1 case), nasopharyngeal carcinoma (1 case), sarcoma NOS (1 case), colon adenocarcinoma (1 case), and malignant melanoma (1 case). CONCLUSIONS: Cutaneous or subcutaneous metastasis of non-hematopoietic malignancies in children and adolescents is a rare occurrence but in a high percentage of cases may be the first manifestation of disease. The tumors most likely to metastasize to the skin in children are rhabdomyosarcoma and neuroblastoma and they are more likely than adult malignancies to disseminate to multiple distant sites.


Assuntos
Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/secundário , Pele/patologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos
15.
Pediatr Dev Pathol ; 2(2): 159-67, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-9949222

RESUMO

Malignant peripheral nerve sheath tumor (MPNST) of bone is a rare entity. We have examined three lesions that fit standard histopathologic criteria for MPNST of soft tissues but that arose in the skeleton of three children aged 6 to 13 years. None was affected by neurofibromatosis 1 (NF1). Histologic features typical of MPNST included spindle cells with comma-shaped nuclei, tactoid bodies, nuclear palisading, hyaline bands, and schwannoma-like and curlicue foci. Epithelioid foci were seen in two cases, and heterologous differentiation in one. Immunohistochemistry revealed positivity for S-100 (1 positive/3 tested), vimentin (3/3), glial fibrillary acidic protein (2/3), CD34 (1/1), and CD68 (1/2). Studies for CD99 (0/3), epithelial membrane antigen (0/3), cytokeratin (0/3), CD57 (0/3), and HMB-45 (0/2) were negative. Ultrastructural findings in one of two cases examined included interlacing, attenuated cytoplasmic processes, microtubules, and rare dense-core granules. We conclude that MPNST may arise as a primary bone neoplasm in children without NF1.


Assuntos
Neoplasias Ósseas/patologia , Neoplasias de Bainha Neural/patologia , Neoplasias do Sistema Nervoso Periférico/patologia , Adolescente , Criança , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Estudos Retrospectivos
16.
Tumour Biol ; 20(1): 30-43, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-9858873

RESUMO

Age-dependent tumor cytolytic functions of tumor-associated macrophages (TAM) obtained from mice bearing different stages of Dalton's lymphoma (DL), a spontaneous T cell lymphoma, were studied. Mice were separated into three groups on the basis of their reproductive status as indicator of age: young (prereproductive); adult (reproductive) and old (postreproductive). DL was injected (1 x 10(5) cells/mouse) intraperitoneally in mice; days 4, 10 and 16 from the day of injection were referred to as early, mid and late tumor stages, respectively. Normal peritoneal macrophages and macrophages isolated from the ascitic fluid of DL-bearing mice (TAM); 1 x 10(5) cells activated with lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma) and assayed for age-dependent alterations in macrophage tumoricidal functions such as: tumor cell binding, cytotoxicity, production of reactive nitrogen intermediates (RNI), expression of inducible nitric oxide synthase (iNOS) and oncostatin-M (OSM) were observed. TAM from old mice were observed to be inhibited with respect to tumor cell binding, cytotoxicity and expression of iNOS and OSM, as compared to macrophages of young and adult mice. TAM obtained from early tumor stages showed augmented tumor cytotoxicity as well as enhanced expression of iNOS and OSM in all the age groups. This effect was most pronounced in the TAM obtained from adult mice and least in the TAM obtained from old mice. The reasons for the observed difference are discussed. These observations should be helpful in understanding the effect of progressive tumor growth and age on the functions of TAM and their responsiveness towards therapeutic manipulations.


Assuntos
Envelhecimento/imunologia , Linfoma de Células T/imunologia , Macrófagos Peritoneais/imunologia , Envelhecimento/metabolismo , Animais , Antineoplásicos/farmacologia , Cálcio/metabolismo , Citotoxicidade Imunológica , Feminino , Humanos , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Antígeno-1 Associado à Função Linfocitária/biossíntese , Linfoma de Células T/metabolismo , Linfoma de Células T/patologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/biossíntese , Óxido Nítrico Sintase Tipo II , Oncostatina M , Peptídeos/metabolismo
17.
Pediatr Pathol Lab Med ; 18(1): 97-113, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9566287

RESUMO

An extremely aggressive malignant epithelial neoplasm of the kidney has recently been described and named renal medullary carcinoma. The finding of this tumor is highly predictive of drepanocytes (sickle cells) in tissue sections and thus the presence of sickle hemoglobin, specifically sickle cell trait, in the patient. We present a case report of this rare tumor in a 10-year-old male. The tumor displayed a variable histologic architecture including gland-like areas with intra- and extracytoplasmic material resembling mucin with hematoxylin and eosin stain. This material was negative with periodic acid-Schiff and mucicarmine stains, stained only weakly with Alcian Blue, and was positive using antibodies against peanut agglutinin. Tumor cells stained positively with antibodies to epithelial membrane antigen, cytokeratin, vimentin, and Ulex europaeus lectin. The luminal face of tumor cells stained with peanut agglutinin. Stains using antibodies against carcinoembryonic antigen and alpha-fetoprotein were negative. Ultrastructurally, the tumor cells were characterized by short microvilli lining the luminal surface and lateral complex infoldings of adjacent plasma membranes. We discuss the relationship of this neoplasm to another renal pelvic neoplasm, collecting duct carcinoma, which may rarely occur in children. Renal medullary carcinoma should be included in the differential diagnosis of gross hematuria, which is most commonly benign self-limited hematuria, in young patients with sickle cell trait.


Assuntos
Carcinoma Medular/complicações , Carcinoma Medular/patologia , Neoplasias Renais/complicações , Neoplasias Renais/patologia , Traço Falciforme/complicações , Adolescente , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Medular/diagnóstico , Criança , Diagnóstico Diferencial , Hematúria/complicações , Humanos , Neoplasias Renais/diagnóstico , Masculino , Microscopia Eletrônica
18.
J Cutan Pathol ; 25(1): 2-10, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9508337

RESUMO

Substance P (SP) is a neuropeptide found in both the central and peripheral nervous system. In the skin, SP-containing neurons stimulate the release of histamine from connective tissue mast cells (MC). SP also can potentiate neoangiogenesis and induce dermal fibrosis. MC-derived histamine has potent vasoactive effects, is angiogenic, and promotes tissue fibroplasia. In addition to histamine, MC contain many other angiogenic factors and a variety of cytokines, growth factors, and proteolytic enzymes implicated in tissue remodeling, and normal as well as tumor-associated neoangiogenesis. Many MC-derived factors, including histamine, can enhance melanoma cell growth directly. MC often concentrate around cutaneous melanomas which also frequently are associated with angiogenesis and peritumoral fibrosis. The precise mediators of these responses have not been well defined. We evaluated by immunohistochemistry cutaneous lesions representing stages of progression of malignant melanoma and its precursor lesions for the expression of SP. SP was expressed in 17/25 (68%) primary invasive malignant melanomas, 2/5 (40%) metastatic melanomas, 6/10 (60%) melanomas in situ, 7/12 (58%) atypical (dysplastic) nevi, and 4/10 (40%) spindle and epithelioid cell (Spitz) nevi, but was not detected in any (0/11, 0%) acquired benign melanocytic nevi (p<0.05). Invasive melanomas were immunolabeled in both the intraepidermal and the dermal components of the lesions. For those atypical and Spitz nevi which expressed SP, most of the immunoreactive melanocytes were located at the dermal-epidermal junction overlying areas of papillary dermal fibrosis. The results show differential expression of SP among cutaneous melanocytic lesions and suggest that the expression of this neuropeptide together with other factors may contribute to some of the host responses associated with these lesions.


Assuntos
Mastócitos/metabolismo , Melanoma/metabolismo , Neoplasias Cutâneas/metabolismo , Substância P/biossíntese , Progressão da Doença , Síndrome do Nevo Displásico/metabolismo , Síndrome do Nevo Displásico/patologia , Humanos , Imuno-Histoquímica/métodos , Mastócitos/patologia , Melanoma/patologia , Melanoma/secundário , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/patologia , Estudos Retrospectivos , Neoplasias Cutâneas/patologia
19.
Nat Immun ; 16(5-6): 215-27, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-11061590

RESUMO

The present investigation was carried out to study the effect of tumor growth on the spleen of an aged host. Dalton's lymphoma (DL), a spontaneous T cell lymphoma, was grown in mice of different age groups classified as young, adult or old on the basis of their reproductive status. Splenocytes obtained from normal and tumor-bearing young, adult and old mice were checked for an in vitro blastogenic response to concanavalin A (Con A), colony-forming ability and apoptosis. There was an enhanced apoptosis of splenocytes and a concomitant inhibition of splenocyte blastogenesis and their responsiveness to the mitogenic stimulus of Con A in aged mice. The counts of granulocyte macrophage- and macrophage-colony forming units were significantly enhanced in the spleen of tumor-bearing adult mice. It is proposed that the DL-growth-dependent increase in the size of the spleen in adult mice is due to an increased blastogenesis of splenocytes, which, however, may not be applicable in the case of old tumor-bearing mice. The role of splenic macrophages in the regulation of the functions of the spleen by macrophage-derived NO is shown.


Assuntos
Envelhecimento/imunologia , Envelhecimento/patologia , Linfoma de Células T/imunologia , Linfoma de Células T/patologia , Baço/imunologia , Baço/patologia , Envelhecimento/metabolismo , Animais , Apoptose , Sobrevivência Celular , Ensaio de Unidades Formadoras de Colônias , Concanavalina A/farmacologia , Feminino , Técnicas In Vitro , Ativação Linfocitária/efeitos dos fármacos , Linfoma de Células T/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Baço/metabolismo
20.
J Am Assoc Gynecol Laparosc ; 4(5): 583-6, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9348365

RESUMO

STUDY OBJECTIVES: To use Chlamydia trachomatis immunoglobulin-gamma (IgG) titers to investigate the possibility of their association with ovarian cancer, and to evaluate the effectiveness of this titer in algorithmic protocols in infertility. DESIGN: Prospective, age-matched, pilot study (Canadian Task Force classification II-2). SETTING: University and university-affiliated office practice. PATIENTS: The original 30 patients were seen for follow-up of ovarian cancer (19) and at yearly examination for nonmalignant disease (10). An additional group of 21 women seen for pelvic pain and infertility was added to clarify questions that arose during the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Chlamydia trachomatis IgG titers were positive in 15 (79%) of 19 of women with ovarian cancer, 9 (90%) of 10 age-matched controls, and 14 (67%) of 21 patients with infertility and pain. When analyzed by age, 4 (40%) of 10 patients under 30 years and 34 (85%) of 40 patients 30 years of age or older had positive titers (p = 0.007). Of 21 women with positive Chlamydia pneumoniae titers, 17 (81 %) had positive C. trachomatis titers, and 17 (85%) of 20 with positive C. trachomatis titers had positive C. pneumoniae titers. CONCLUSION: The test kit used in this study may not be adequate in older patients due to cross-reaction with C. pneumoniae titers. Further evaluation of C. trachomatis IgG titers as a marker in the study of ovarian cancer will require titers that are more specific than those we used. Although these titers may be useful as an immunologic screening marker in infertile patients, results should be interpreted with caution. A positive test may not be evidence of C. trachomatis infection and is not an indication for specific therapy. Successful use of some currently available C. trachomatis IgG titers in algorithms for infertility may be related to a patient's age.


Assuntos
Envelhecimento/imunologia , Infecções por Chlamydia/imunologia , Chlamydia trachomatis/isolamento & purificação , Chlamydophila pneumoniae/isolamento & purificação , Cadeias gama de Imunoglobulina/sangue , Neoplasias Ovarianas/imunologia , Adolescente , Adulto , Idoso , Algoritmos , Biomarcadores/sangue , Infecções por Chlamydia/diagnóstico , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/sangue , Dor Pélvica/diagnóstico , Dor Pélvica/imunologia , Projetos Piloto , Probabilidade , Estudos Prospectivos , Valores de Referência , Sensibilidade e Especificidade
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