Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
1.
J Econ Entomol ; 116(6): 2184-2192, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-37816495

RESUMO

Western corn rootworm, Diabrotica virgifera virgifera (LeConte) (Coleoptera: Chrysomelidae), is the most serious economic pest of maize, Zea mays (L.) (Poales: Poaceae), in the U.S. Corn Belt and also threatens production in Europe. Traditional management options have repeatedly failed over time as western corn rootworm rapidly develops resistance to insecticides, transgenic maize and even crop rotation. Traits that improve host plant resistance and tolerance are highly sought after by plant breeders for crop protection and pest management. However, maize resistance to western corn rootworm appears to be highly complex and despite over 75 yr of breeding efforts, there are no naturally resistant hybrids available commercially. Using phenotypic data from field and greenhouse experiments on a highly diverse collection of 282 inbred lines, we screened and genetically mapped western corn rootworm-related traits to identify genetic loci which may be useful for future breeding or genetic engineering efforts. Our results confirmed that western corn rootworm resistance is complex with relatively low heritability due in part to strong genotype by environment impacts and the inherent difficulties of phenotyping below ground root traits. The results of the Genome Wide Associated Study identified 29 loci that are potentially associated with resistance to western corn rootworm. Of these loci, 16 overlap with those found in previous transcription or mapping studies indicating a higher likelihood they are truly involved in maize western corn rootworm resistance. Taken together with previous studies, these results indicate that breeding for natural western corn rootworm resistance will likely require the stacking of multiple small effect loci.


Assuntos
Besouros , Animais , Besouros/genética , Zea mays/genética , Estudo de Associação Genômica Ampla , Defesa das Plantas contra Herbivoria , Plantas Geneticamente Modificadas/genética , Melhoramento Vegetal , Larva , Endotoxinas , Controle Biológico de Vetores
2.
BMJ Mil Health ; 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37696654

RESUMO

Administration of medication is a well-established part of prehospital trauma care. Guidance varies on the types of recommended medications and when they should be administered. Mnemonics have become commonplace in prehospital medicine to facilitate recall and retention. However, there is no comprehensive aid for the administration of medication in trauma patients. We propose a new mnemonic for the delivery of relevant intravenous or intraosseous medications in trauma patients. A '4A after Access' approach should enhance memory recall for the efficient provision of patient care. These 4As are: antifibrinolysis, analgesia, antiemesis and antibiotics. This mnemonic is designed to be used as an optional aide memoire in conjunction with existing treatment algorithms in the military prehospital setting.

3.
J Cancer Surviv ; 15(4): 630-640, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33067774

RESUMO

PURPOSE: Relatively little is known about caregivers of African American cancer survivors. Our goal was to identify the extent of burden among this group of caregivers. METHODS: Responses from 560 informal caregivers of African American participants of the Research on Cancer Survivors (ROCS) study in Detroit, MI, were analyzed including demographics, assistance provided including activities of daily living (ADLs) and instrumental activities of daily living (IADLs), time spent in caregiving, and caregiver burden (CGB). We assessed relationships between CGB and demographic variables, ADLs/IADLs, and level of care. Multivariable logistic regression determined which ADLs and IADLs were associated with high CGB. RESULTS: Over 75% of caregivers were female and 97% identified as African American. Mean age was 52.6 years. Fifty-six percent were employed outside the home, and 90% were related to the survivor. Caregivers averaged 35.7 h/week providing care, assisting with on average 2.8 ADLs and 5.0 IADLs. Despite the many hours and activities reported, no caregivers rated CGB as severe; only 4% rated it moderate to severe. ADLs associated with the top quartile of CGB were feeding and toileting; IADLs were finances, telephoning, housework, and medications. CONCLUSIONS: Caregivers for African American cancer survivors provide many hours of care, yet most describe their CGB as low. Although ADL assistance is often available through the healthcare system, assistance with IADLs presents an opportunity to lessen the burden for these caregivers and their care recipients. IMPLICATIONS FOR CANCER SURVIVORS: African American cancer survivors receive much care from informal family caregivers, who assist with multiple ADLs and IADLs. Formal IADL assistance programs, similar to those available for ADLs, would benefit both survivors and caregivers.


Assuntos
Sobreviventes de Câncer , Neoplasias , Atividades Cotidianas , Negro ou Afro-Americano , Cuidadores , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias/terapia
4.
Ann R Coll Surg Engl ; 101(6): 379-386, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30855983

RESUMO

INTRODUCTION: Public awareness campaigns have led to increasing referrals of patients to colorectal surgery for possible cancer. Change in bowel habit, is traditionally described as a symptom of a left sided bowel cancer. If this is the case in practice, it raises the potentially attractive option of investigating such patients with flexible sigmoidoscopy only. This study sought to systematically review the literature describing tumour location of patients with bowel cancer presenting with left-sided symptoms to establish the safety of potential investigation of these patients with flexible sigmoidoscopy alone. METHODS: A systematic review of studies reporting both the presenting symptoms of patients with bowel cancer and the location of their cancer in the bowel was prospectively registered (CRD42017072492). MEDLINE, EMBASE and CENTRAL were searched with no date or language restriction. RESULTS: Seven studies were included. Isolated change in bowel habit (with or without rectal bleeding) was a presenting symptom of 73% (95% CI 41-96%, I2 = 99%) of left-sided cancers but also in 13% (95% CI 2-30%, I2 = 96%) of right-sided cancers. In all patients with cancer who presented with isolated change in bowel habit (with or without rectal bleeding), the cancer was right sided in 8% (95% CI 4-12%, I2 = 69%). CONCLUSIONS: There is a higher than expected risk that if a cancer is diagnosed in a patient presenting with either an isolated change in bowel habit or a combination of change in bowel habit with rectal bleeding, the cancer may be right sided.


Assuntos
Neoplasias Colorretais/diagnóstico , Sigmoidoscopia , Humanos , Sigmoidoscopia/efeitos adversos
5.
BMC Public Health ; 16: 103, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26830343

RESUMO

BACKGROUND: School participation in collecting and reporting syndromic surveillance (SS) data to public health officials and school nurses' attitudes regarding SS have not been assessed. METHODS: An online survey was sent to Missouri Association of School Nurses members during the 2013/2014 school year to assess whether K-12 schools were collecting and reporting SS data. Z-scores were used to assess collection versus reporting of SS indicators. Logistic regressions were used to describe factors predicting nurses' collection and reporting of SS indicators: all-cause absenteeism, influenza-like illness and gastrointestinal illness. Univariate predictors were assessed with Chi-Squares. RESULTS: In total, 133 school nurses participated (33.6 % response rate). Almost all (90.2 %, n = 120) collect at least one SS indicator; half (49.6 %, n = 66) report at least one. Schools are collecting more SS data than they are reporting to the health department (p < .05 for all comparisons). Determinants of school nurses' collection of SS data included perceived administrative support, and knowledge of collecting and analyzing SS data. The strongest predictive factors for reporting SS data were the perception that the health department was interested in SS data and being approached by the health department to collect SS data. CONCLUSION: Schools are collecting SS indicators at a relatively high rate, yet less than half of the data is reported to public health officials. Findings from this study indicate that public health officials can increase access to school-based SS data by approaching schools about collecting and reporting this important data.


Assuntos
Absenteísmo , Coleta de Dados/métodos , Enfermeiras e Enfermeiros , Vigilância em Saúde Pública/métodos , Instituições Acadêmicas/estatística & dados numéricos , Adolescente , Adulto , Criança , Estudos Transversais , Feminino , Gastroenteropatias/epidemiologia , Humanos , Influenza Humana/epidemiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Missouri/epidemiologia
7.
Cell Death Differ ; 17(7): 1155-66, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20111043

RESUMO

Apoptosis-inducing factor (AIF) has important supportive as well as potentially lethal roles in neurons. Under normal physiological conditions, AIF is a vital redox-active mitochondrial enzyme, whereas in pathological situations, it translocates from mitochondria to the nuclei of injured neurons and mediates apoptotic chromatin condensation and cell death. In this study, we reveal the existence of a brain-specific isoform of AIF, AIF2, whose expression increases as neuronal precursor cells differentiate. AIF2 arises from the utilization of the alternative exon 2b, yet uses the same remaining 15 exons as the ubiquitous AIF1 isoform. AIF1 and AIF2 are similarly imported to mitochondria in which they anchor to the inner membrane facing the intermembrane space. However, the mitochondrial inner membrane sorting signal encoded in the exon 2b of AIF2 is more hydrophobic than that of AIF1, indicating a stronger membrane anchorage of AIF2 than AIF1. AIF2 is more difficult to be desorbed from mitochondria than AIF1 on exposure to non-ionic detergents or basic pH. Furthermore, AIF2 dimerizes with AIF1, thereby preventing its release from mitochondria. Conversely, it is conceivable that a neuron-specific AIF isoform, AIF2, may have been 'designed' to be retained in mitochondria and to minimize its potential neurotoxic activity.


Assuntos
Fator de Indução de Apoptose/metabolismo , Encéfalo/metabolismo , Mitocôndrias/metabolismo , Sequência de Aminoácidos , Animais , Fator de Indução de Apoptose/química , Fator de Indução de Apoptose/genética , Proteínas Reguladoras de Apoptose/química , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Humanos , Camundongos , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Neurônios/citologia , Neurônios/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Alinhamento de Sequência
8.
Cell Death Differ ; 14(5): 1029-39, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17256008

RESUMO

The reduction of intracellular 1,4,5-inositol trisphosphate (IP(3)) levels stimulates autophagy, whereas the enhancement of IP(3) levels inhibits autophagy induced by nutrient depletion. Here, we show that knockdown of the IP(3) receptor (IP(3)R) with small interfering RNAs and pharmacological IP(3)R blockade is a strong stimulus for the induction of autophagy. The IP(3)R is known to reside in the membranes of the endoplasmic reticulum (ER) as well as within ER-mitochondrial contact sites, and IP(3)R blockade triggered the autophagy of both ER and mitochondria, as exactly observed in starvation-induced autophagy. ER stressors such as tunicamycin and thapsigargin also induced autophagy of ER and, to less extent, of mitochondria. Autophagy triggered by starvation or IP(3)R blockade was inhibited by Bcl-2 and Bcl-X(L) specifically targeted to ER but not Bcl-2 or Bcl-X(L) proteins targeted to mitochondria. In contrast, ER stress-induced autophagy was not inhibited by Bcl-2 and Bcl-X(L). Autophagy promoted by IP(3)R inhibition could not be attributed to a modulation of steady-state Ca(2+) levels in the ER or in the cytosol, yet involved the obligate contribution of Beclin-1, autophagy-related gene (Atg)5, Atg10, Atg12 and hVps34. Altogether, these results strongly suggest that IP(3)R exerts a major role in the physiological control of autophagy.


Assuntos
Autofagia , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Animais , Autofagia/genética , Cálcio/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Privação de Alimentos , Células HeLa , Humanos , Inositol 1,4,5-Trifosfato/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/antagonistas & inibidores , Compostos Macrocíclicos/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Oxazóis/farmacologia , Isoformas de Proteínas/metabolismo , Ratos , Proteína bcl-X/metabolismo
10.
Biol Bull ; 209(2): 113-26, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16260771

RESUMO

Gamete interactions may strongly influence speciation and hybridization in sympatric broadcast-spawning marine invertebrates. We examined the role of gamete compatibility in species integrity using cross-fertilization studies between sympatric Asterias sea stars from a secondary contact zone in the northwest Atlantic. In crosses between single males and single females, gametes of both species were compatible and produced viable, fertile hybrid offspring, but with considerable variation in the receptivity of eggs to heterospecific sperm. Differential compatibility of heterospecific gametes was detected in sperm competition studies in which we used a nuclear DNA marker to assign paternity to larval offspring. Several families showed conspecific sperm precedence in A. forbesi eggs, and one family showed competitive superiority of A. forbesi sperm fertilizing A. rubens eggs. Gametic interactions are an important component of prezygotic reproductive isolation in sympatric Asterias. The interaction between gametes of these closely related sea stars is consistent with the function of gamete recognition systems that are known to mediate fertilization success and speciation in other marine invertebrates.


Assuntos
Hibridização Genética/fisiologia , Espermatozoides/fisiologia , Estrelas-do-Mar/fisiologia , Animais , Cruzamentos Genéticos , Feminino , Fertilização/fisiologia , Masculino , Nova Escócia , Especificidade da Espécie
11.
Ann Thorac Surg ; 72(4): 1409-10, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11603487

RESUMO

The vacuum-assisted closure (VAC; KCI International, San Antonio, TX) device is a negative pressure dressing, which we have used in the treatment of wounds with devitalized or infected tissues. Although introduced in plastic and reconstructive surgery, its use has extended to orthopedic and cardiothoracic surgical practice in the treatment of infected joint replacement and sternal wound infections, respectively. Although the VAC is becoming more widely used in surgical practice, only a small number of case reports exist in addition to the original case series by Argenta and Morykwas in 1997. Previously, the device was described in treating single wounds in adult patients. We report a case where it was successfully used to treat multiple dog bite injuries in a 9-year-old child.


Assuntos
Mordeduras e Picadas/cirurgia , Traumatismo Múltiplo/cirurgia , Curativos Oclusivos , Infecções por Pseudomonas/cirurgia , Traumatismos Torácicos/cirurgia , Infecção dos Ferimentos/cirurgia , Animais , Criança , Desbridamento , Cães , Feminino , Humanos , Sucção/instrumentação , Vácuo
12.
Arch Environ Contam Toxicol ; 40(1): 77-88, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11116343

RESUMO

Forensic evaluation of aldicarb exposure is difficult due to the rapid hydrolysis and oxidation of the parent compound. Oxidation products-aldicarb sulfoxide and aldicarb sulfone-are commonly analyzed, but hydrolytic products-aldicarb nitrile, aldicarb nitrile sulfoxide, aldicarb nitrile sulfone-are infrequently analyzed even though they are the primary stable products of aldicarb degradation. Nitrile analyses provide an important avenue to verify aldicarb exposure or aldicarb-induced mortality. Our aproach allows lethal and sublethal exposure assessment. Extraction of samples with acetonitrile:water is followed by chromatographic determination. Sublethal exposure assessment utilizes excreta samples, which is nonlethal and requires holding animals in captivity for 12 h or less. Sublethal exposures of northern bobwhite Colinus virginianus to aldicarb can be identified with greater than 80% confidence for 6 h after dosing. By analyzing GI tracts, lethal exposures of bobwhite to aldicarb can be identified with greater than 90% confidence for 4 days post mortem and with 75% confidence for 8 days post mortem. Sublethal exposures to aldicarb was identified in greater than 80% of Peromyscus maniculatis for 6 h after dosing. Aldicarb and its transformation products were detected for 8 days post mortem in all mice that received aldicarb doses at or above the LD50.


Assuntos
Aldicarb/toxicidade , Colinus , Medicina Legal/métodos , Inseticidas/toxicidade , Peromyscus , Aldicarb/análise , Aldicarb/metabolismo , Animais , Sistema Digestório/química , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/metabolismo , Exposição Ambiental/análise , Monitoramento Ambiental , Fezes/química , Moela das Aves/química , Moela das Aves/efeitos dos fármacos , Moela das Aves/metabolismo , Inseticidas/análise , Inseticidas/metabolismo , Dose Letal Mediana
13.
J Immunol ; 161(7): 3375-83, 1998 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-9759854

RESUMO

We examined the effects of the cell-permeable, broad spectrum peptide caspase inhibitors, benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD.fmk), and BOC-Asp(OMe)-fluoromethyl ketone (BOC-D.fmk), on apoptosis induced by anti-CD2, anti-Fas, and the protein kinase inhibitor staurosporine in activated human peripheral T lymphocytes. We monitored ultrastructural, flow cytometric, and biochemical apoptotic changes, including externalization of phosphatidylserine, cleavage of poly(ADP-ribose) polymerase (PARP) and lamins, activation of caspase-3 and caspase-7, decrease in mitochondrial membrane potential, and DNA fragmentation. Z-VAD.fmk and BOC-D.fmk completely inhibited all the biochemical and ultrastructural changes of apoptosis in anti-Fas-treated cells. In marked contrast, neither Z-VAD.fmk nor BOC-D.fmk inhibited CD2- or staurosporine-mediated cell shrinkage, dilatation of the endoplasmic reticulum (seen in anti-CD2-treated cells), externalization of phosphatidylserine, and loss of mitochondrial membrane potential that accompanied cell death. However, these inhibitors did inhibit the cleavage of PARP and lamins and the formation of hypodiploid cells, and partially inhibited chromatin condensation. These results demonstrate that in activated T cells, anti-CD2 and staurosporine induce a caspase-independent cell death pathway that exhibits prominent cytoplasmic features of apoptosis. However, caspase activation is required for the proteolytic degradation of nuclear substrates such as PARP and lamins together with the DNA fragmentation and extreme chromatin condensation that occur in apoptotic cells.


Assuntos
Anticorpos Monoclonais/farmacologia , Apoptose/imunologia , Antígenos CD2/imunologia , Caspases , Cisteína Endopeptidases/fisiologia , Ativação Linfocitária , Estaurosporina/farmacologia , Subpopulações de Linfócitos T/imunologia , Clorometilcetonas de Aminoácidos/farmacologia , Apoptose/efeitos dos fármacos , Antígenos CD2/efeitos dos fármacos , Caspase 2 , Caspase 3 , Caspase 7 , Morte Celular/efeitos dos fármacos , Morte Celular/imunologia , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Diploide , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/imunologia , Humanos , Hidrólise/efeitos dos fármacos , Laminas , Ativação Linfocitária/efeitos dos fármacos , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas/metabolismo , Estaurosporina/antagonistas & inibidores , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/enzimologia , Subpopulações de Linfócitos T/ultraestrutura , Receptor fas/efeitos dos fármacos , Receptor fas/imunologia , Receptor fas/fisiologia
14.
J Radiol Prot ; 18(4): 249-64, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9915639

RESUMO

The development of two probabilistic accident consequence codes sponsored by the European Commission and the United States Nuclear Regulatory Commission, COSYMA and MACCS respectively, was completed in 1990. These codes estimate the risks and other endpoints associated with accidents from hypothesised nuclear installations. In 1991, both commissions sponsored a joint project for an uncertainty analysis of these two codes. The main objective of this joint project was to systematically derive credible and traceable probability distributions for the respective code input variables. These input distributions will subsequently be used in two uncertainty analyses for each code separately. A formal expert judgement elicitation and evaluation process was used as the best available technique to accomplish that objective. This paper describes the process and some of the findings of the eight expert judgement exercises performed under the joint study.


Assuntos
Modelos Estatísticos , Lesões por Radiação , Liberação Nociva de Radioativos , Animais , Atmosfera , Simulação por Computador , União Europeia , Prova Pericial , Cadeia Alimentar , Órgãos Governamentais , Humanos , Cooperação Internacional , Probabilidade , Doses de Radiação , Proteção Radiológica , Cinza Radioativa , Medição de Risco , Estados Unidos
15.
Anal Chem ; 70(15): 3329-32, 1998 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11013730

RESUMO

Carbamate insecticide screens often include aldicarb and its oxidative metabolites, aldicarb sulfoxide (ASX), and aldicarb sulfone (ASN). The rapid hydrolysis and thermal cleavage of the C-N bond within the carbamate functional group of these compounds produces nitrile transformation products. Nitriles are primary transformation products from aldicarb, its sulfoxide, or its sulfone. However, these nitriles are infrequently monitored. The method reported used acetonitrile/water extraction and HPLC postcolumn derivitization to determine aldicarb, ASX, and ASN from avian excreta and from gastrointestinal (GI) tissue. Recoveries of aldicarb, ASX and ASN from excreta were of 79% +/- 5.4, 120% +/- 7.7, and 93% +/- 6.2, respectively. Recoveries from tissue were 70% +/- 5.0, 80% +/- 12.1, and 85% +/- 6.7, respectively. The same extraction procedure and a GC-FPD analysis were used to determine nitrile metabolites from the same tissues. Aldicarb nitrile, ASX nitrile, and ASN nitrile recoveries from excreta were 42% +/- 2.3, 65% +/- 3.6, and 79% +/- 3.3, respectively. Overall recoveries from tissue were 29% +/- 3.4, 72% +/- 8.3, and 83% +/- 11.4, respectively. Since aldicarb, ASX, and ASN are normally detectable in organ tissues for 1-2 days following exposure, determining the presence of nitrile cleavage products provides an important forensic tool for evaluating aldicarb exposures.


Assuntos
Aldicarb/isolamento & purificação , Sistema Digestório/química , Fezes/química , Inseticidas/isolamento & purificação , Urinálise/métodos , Aldicarb/metabolismo , Animais , Técnicas de Química Analítica/métodos , Inseticidas/metabolismo , Camundongos
16.
Mol Cell Biol ; 17(4): 2116-26, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9121460

RESUMO

The human and murine MOK2 ortholog genes that are preferentially expressed in brain and testis tissues encode two different Krüppel-like zinc finger proteins. In this paper, we show that the MOK2 proteins are mainly associated with nuclear ribonucleoprotein components, including the nucleoli and extranucleolar structures, and exhibit specific RNA homopolymer binding activities. Moreover, we have identified an identical 18-bp specific DNA binding sequence for both MOK2 proteins using a pool of random sequence oligonucleotides. The DNA binding domain is localized in the seven adjacent zinc finger motifs, which show 94% identity between human and murine proteins. Taken together, these results establish that the MOK2 proteins are able to recognize both DNA and RNA through their zinc fingers. This dual affinity and the subnuclear localization suggest that MOK2 may play roles in transcription, as well as in the posttranscriptional regulation processes of specific genes.


Assuntos
Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , RNA/metabolismo , Ribonucleoproteínas/metabolismo , Animais , Sequência de Bases , Sítios de Ligação/genética , Sequência Consenso , DNA/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Células HeLa , Humanos , Células L , Masculino , Camundongos , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Ribonucleoproteínas/química , Transfecção , Dedos de Zinco
17.
Proc Natl Acad Sci U S A ; 94(4): 1200-5, 1997 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-9037030

RESUMO

There is now abundant evidence to substantiate an important role of hepatitis C virus (HCV) core protein in cellular gene expression as well as in the viral cycle. Thus the subcellular localization of this protein has important implications. However, several studies have shown controversial results: the HCV core has been, indeed, described as cytoplasmic or nuclear depending on the size of the protein or on the genotype analyzed. We have studied the localization of the HCV core protein in two different cell lines, one nonhepatic (CHO) and the other hepatic (HepG2). Double immunofluorescence staining using a nuclear membrane marker and confocal analysis showed the core protein pattern to be cytoplasmic and globular. This pattern is not cell cycle-regulated. Electron microscopy analysis revealed the nature of the globular staining observed in immunofluorescence. The HCV core protein accumulated at the surface of lipid droplets that were also the unique morphological feature of nonhepatic core transfected cells. The lipid droplets were isolated by sequential ultracentrifugation on the basis of their density; biochemical analysis revealed a prevalence of triglycerides. In addition the core protein colocalized with apolipoprotein AII at the surface of the lipid droplets as revealed by confocal microscopy. Moreover analysis of liver biopsies from chronically HCV-infected chimpanzees revealed that HCV core is cytoplasmic and localized on the endoplasmic reticulum and on lipid droplets. These results clearly define the subcellular localization of the HCV core protein and suggest a relationship between the expression of the HCV core protein and cellular lipid metabolism.


Assuntos
Compartimento Celular , Citoplasma/química , Lipídeos/isolamento & purificação , Proteínas do Core Viral/isolamento & purificação , Animais , Apolipoproteína A-II/isolamento & purificação , Células CHO , Ciclo Celular , Cricetinae , Citoplasma/ultraestrutura , Técnica Indireta de Fluorescência para Anticorpo , Hepatite C , Humanos , Fígado/virologia , Microscopia Confocal , Microscopia Imunoeletrônica , Pan troglodytes , Proteínas Recombinantes/isolamento & purificação , Frações Subcelulares/química , Triglicerídeos/análise , Proteínas do Core Viral/genética
18.
Cell Growth Differ ; 8(2): 165-78, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9040938

RESUMO

SV40 T antigen (LT) is an oncoprotein that inactivates nuclear regulators such as retinoblastoma (RB) family proteins and p53. We recently reported that in Madin-Darby canine kidney (MDCK) epithelial cells the binding of LT to RB family proteins results in a massive apoptosis and a concomitant down-regulation of c-myc. Here, we show that LT causes loss of epithelial differentiation and induces invasiveness. MDCK cells expressing wild-type LT, but not mutants unable to bind RB, exhibit a fibroblast-like morphology, show a strong down-regulation of the vHNF1 transcription factor and acquire invasive properties. The stable retransformation of MDCK(LT) with a RB and/or c-myc-expressing vector restores the expression of epithelial characteristics. Our data therefore suggest an important role for RB and c-myc in modulating the epithelial phenotype both during normal tissue development and in invasive processes. In addition, when grown in collagen gels, the MDCK(LT) cells form branching tubules, and their conditioned media produce the scattering of monolayer cultured MDCK cells. These last properties are reminiscent of those induced by hepatocyte growth factor/scatter factor (HGF/SF). Moreover, the HGF/SF protein was detected by Western blotting in the MDCK(LT)-conditioned medium. The production of HGF/SF is specifically induced by LT-RB inactivation, because Ras transformation of MDCK cells fails to induce the production of this factor. These results demonstrate that inactivation of RB family proteins in these cells is at the origin of a HGF/SF autocrine loop.


Assuntos
Antígenos Transformantes de Poliomavirus/farmacologia , Fator de Crescimento de Hepatócito/metabolismo , Proteína do Retinoblastoma/metabolismo , Animais , Antígenos Transformantes de Poliomavirus/biossíntese , Biomarcadores , Diferenciação Celular/genética , Linhagem Celular , Proteínas de Ligação a DNA/metabolismo , Cães , Células Epiteliais , Epitélio/metabolismo , Epitélio/patologia , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibroblastos/patologia , Técnicas de Transferência de Genes , Genes myc , Fator 1-beta Nuclear de Hepatócito , Junções Intercelulares/genética , Junções Intercelulares/ultraestrutura , Microvilosidades/genética , Microvilosidades/ultraestrutura , Invasividade Neoplásica/patologia , Invasividade Neoplásica/ultraestrutura , Proteínas Nucleares/metabolismo , Proteína do Retinoblastoma/genética , Fatores de Transcrição/metabolismo
19.
Cell Death Differ ; 3(3): 285-98, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17180097

RESUMO

SV40 T antigen (LT) transformation of renal MDCK epithelial cells resulted in massive apoptosis in the presence of serum. Cell death was dependent on the ability of LT to bind RB or a related protein, since MDCK cells expressing LT mutants unable to bind RB did not die. Apoptosis could be rescued by treatment of cells with EGF and TPA, a property linked to their ability to promote cell growth. Our results indicate an inverse correlation between proliferation and apoptosis. Thus LT transformation induced survival-factor dependence in epithelial cells, in contrast to its effect in fibroblasts. RB inactivation also resulted in a strong down-regulation of c-myc and c-fos, which were previously found to be highly and constitutively expressed in epithelial cells. RB gene transfer in MDCK(LT) cells restored cell viability and high c-myc expression. C-myc gene transfer in these cells also resulted in a significant survival effect. These results suggest that RB anti-cell death activity is at least partly mediated by up-regulation of c-myc. Overexpression of Bcl2 also protected cells against apoptosis. The role of RB and c-myc in cell survival is discussed and related to maintenance of the differentiation state rather than to their properties in cell cycle progression.

20.
Exp Cell Res ; 208(1): 19-34, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7689476

RESUMO

We used a biotinylated poly(dT) probe to localize poly(A) RNA in HeLa cells at optical and electron microscope levels. We established that the fluorescent speckled staining pattern corresponds at the ultrastructural level to the labeling of perichromatin fibrils, at least part of the population of perichromatin granules, and clusters of interchromatin granules. Coiled bodies and the interchromatin granule-associated zones, a recently described subcompartment containing U1 but not U2 snRNA, were not labeled. The density of the labeling of interchromatin granule clusters exceeded by three to five times that of the surrounding extranucleolar area. These results are discussed in relation to the role of perichromatin fibrils in splicing of pre-mRNA and to the possible involvement of interchromatin granules in the assembly of mature spliceosomes as well as in sorting and/or coordination of RNA molecules to be transported to the cytoplasm.


Assuntos
Núcleo Celular/metabolismo , Hibridização In Situ/métodos , Poli A/metabolismo , RNA/metabolismo , Compartimento Celular/efeitos dos fármacos , Núcleo Celular/ultraestrutura , Cromatina/metabolismo , Citoplasma/metabolismo , Dactinomicina/farmacologia , Células HeLa , Temperatura Alta , Humanos , Técnicas In Vitro , Microscopia Eletrônica/métodos , RNA Mensageiro
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA