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1.
Phys Rev Lett ; 129(14): 142502, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36240396

RESUMO

The root mean square radii of the proton density distribution in ^{16-24}O derived from measurements of charge changing cross sections with a carbon target at ∼900A MeV together with the matter radii portray thick neutron skin for ^{22-24}O despite ^{22,24}O being doubly magic. Imprints of the shell closures at N=14 and 16 are reflected in local minima of their proton radii that provide evidence for the tensor interaction causing them. The radii agree with ab initio calculations employing the chiral NNLO_{sat} interaction, though skin thickness predictions are challenged. Shell model predictions agree well with the data.


Assuntos
Nêutrons , Prótons , Carbono
2.
Phys Rev Lett ; 124(10): 102501, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32216444

RESUMO

Interaction cross sections for ^{42-51}Ca on a carbon target at 280 MeV/nucleon have been measured for the first time. The neutron number dependence of derived root-mean-square matter radii shows a significant increase beyond the neutron magic number N=28. Furthermore, this enhancement of matter radii is much larger than that of the previously measured charge radii, indicating a novel growth in neutron skin thickness. A simple examination based on the Fermi-type distribution, and mean field calculations point out that this anomalous enhancement of the nuclear size beyond N=28 results from an enlargement of the core by a sudden increase in the surface diffuseness of the neutron density distribution, which implies the swelling of the bare ^{48}Ca core in Ca isotopes beyond N=28.

3.
Phys Rev Lett ; 124(22): 222504, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32567915

RESUMO

We report the measurement of reaction cross sections (σ_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large σ_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F.

4.
Transpl Infect Dis ; 16(5): 838-42, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25040057

RESUMO

Renal transplant recipients may present with intracranial space-occupying lesions (SOLs) due to infections as well as a post-transplant lymphoproliferative disorder (PTLD). Here, we discuss a renal transplant recipient who presented with neurologic symptoms and magnetic resonance imaging (MRI) of the brain showed multiple focal SOLs. Tuberculosis (TB), toxoplasmosis, nocardiosis, fungal infections, and PTLD were considered in the differential diagnosis. MRI spectroscopy was suggestive of an infectious cause, such as toxoplasmosis or TB. Serologic tests using Toxoplasma were negative. A brain biopsy followed by immunohistochemical staining using Toxoplasma antibody demonstrated multiple intravascular cysts of toxoplasma. This case highlights the diagnostic dilemma in an immunocompromised patient with multiple focal brain lesions, especially in areas where TB is endemic.


Assuntos
Transplante de Rim/efeitos adversos , Toxoplasmose Cerebral/diagnóstico , Tuberculoma Intracraniano/diagnóstico , Adulto , Infecções Fúngicas do Sistema Nervoso Central/diagnóstico , Diagnóstico Diferencial , Humanos , Índia , Transtornos Linfoproliferativos/diagnóstico , Transtornos Linfoproliferativos/etiologia , Imageamento por Ressonância Magnética , Masculino , Nocardiose/diagnóstico , Toxoplasmose Cerebral/tratamento farmacológico
5.
Mymensingh Med J ; 32(2): 412-420, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37002752

RESUMO

The study was intended to evaluate efficacy of Intra-arterial nitroglycerin through the sheath at the end of a transradial procedure to preserve the patency of the radial artery. This prospective observational study was done in the Department of Cardiology, National Institute of Cardiovascular Diseases (NICVD), Dhaka, Bangladesh from May 2017 to April 2018, by including a total 200 patients undergoing coronary procedures (CAG and / or PCI) through TRA. RAO was defined as an absence of antegrade flow or monophasic flow or invert flow on Doppler study. In this study 102 patients (Group I) received 200 mcg intra-arterial nitroglycerine, prior to trans-radial sheath removal. Another 98 patients (Group II) did not receive intra-arterial nitroglycerine prior to trans-radial sheath removal. Conventional haemostatic compression methods were applied (average 2 hours) in both groups of patients. Evaluation of radial arterial arterial blood flow by colour Doppler study was done on next day after the procedure in both groups. Results of this study in which RAO was determined by vascular doppler study showed that frequency of radial artery occlusion were 13.5% one day after transradial coronary procedures. We found the incidence was 8.8% vs. 18.4%, (p=0.04) in Group I and Group II respectively. The incidence of RAO was significantly lower in post procedural nitroglycerine group. From multivariate logistic regression analysis diabetes mellitus (p = 0.02), hemostatic compression time for more than 02 hours after sheath removal (p = <0.001) and procedure time (p = 0.02) was predictors of RAO. So, the administration of nitroglycerin at the end of a transradial catheterization reduced the incidence of RAO, as shown by 1 day after the radial procedure by doppler ultrasound.


Assuntos
Arteriopatias Oclusivas , Intervenção Coronária Percutânea , Humanos , Nitroglicerina/uso terapêutico , Artéria Radial/diagnóstico por imagem , Intervenção Coronária Percutânea/efeitos adversos , Cateterismo Cardíaco/métodos , Bangladesh , Ultrassonografia Doppler/efeitos adversos , Ultrassonografia Doppler/métodos , Arteriopatias Oclusivas/etiologia , Arteriopatias Oclusivas/prevenção & controle , Arteriopatias Oclusivas/epidemiologia
6.
Science ; 382(6671): 679-683, 2023 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-37943897

RESUMO

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.


Assuntos
Variação Biológica da População , Herbivoria , Defesa das Plantas contra Herbivoria , Plantas , Ecossistema , Filogenia , Animais , Evolução Biológica
7.
Water Sci Technol ; 61(10): 2563-73, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20453329

RESUMO

Low-temperature carbonization (LTC) of coal generates highly complex wastewater warranting stringent treatment. Developing a techno-economically viable treatment facility for such wastewaters is a challenging task. The paper discusses a case study pertaining to an existing non-performing effluent treatment plant (ETP). The existing ETP comprising an ammonia stripper followed by a single stage biological oxidation was unable to treat 1,050 m(3)/d of effluent as per the stipulated discharge norms. The treated effluent from the existing ETP was characterized with high concentrations of ammonia (75-345 mg N/l), COD (313-1,422 mg/l) and cyanide (0.5-4 mg/l). Studies were undertaken to facilitate recycling/reuse of the treated effluent within the plant. A second stage biooxidation process was investigated at pilot scale for the treatment of the effluent from the ETP. This was further subjected to tertiary treatment with 0.5% dose of 4% hypochlorite which resulted in effluent with pH: 6.6-6.8, COD: 73-121 mg/l, and BOD(5):<10 mg/l. Phenol, cyanide and ammonia were below detectable limits and the colourless effluent was suitable for recycle and reuse. Thus, a modified treatment scheme comprising ammonia pre-stripping followed by two-stage biooxidation process and a chemical oxidation step with hypochlorite at tertiary stage was proposed for recycle/reuse of LTC wastewater.


Assuntos
Combustíveis Fósseis , Eliminação de Resíduos Líquidos/métodos , Amônia/análise , Carbono , Carvão Mineral , Coque , Conservação dos Recursos Naturais , Desenho de Equipamento , Gases/análise , Gases/isolamento & purificação , Metais Pesados/análise , Naftalenos/análise , Oxirredução , Projetos Piloto , Purificação da Água/métodos
8.
Mol Cell Biol ; 13(10): 6537-46, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8413252

RESUMO

The transcription factor E2F has been shown to be involved in the expression of several cell cycle-regulated genes, and the activity of this factor is controlled by cellular proteins such as pRB and p107. E2F is also a target of the DNA virus oncoproteins (adenovirus E1A, simian virus 40 T antigen, and human papillomavirus [HPV] E7) (see the review by J. R. Nevins [Science 258: 424-429, 1992]). These viral oncoproteins dissociate an inactive complex between E2F and the retinoblastoma tumor suppressor protein (pRB), and this dissociation of the E2F-pRB complex correlates with a stimulation of the E2F-dependent transcription. In the S phase of the cell cycle, E2F forms a complex with p107, cyclin A, and the cdk2 kinase (E2F-cyclin A complex). The cellular function of this S-phase-specific complex is unclear. The adenovirus E1A protein dissociates the E2F-cyclin A complex. The HPV type 16 (HPV-16) E7 protein, which possesses significant sequence homology with E1A, does not dissociate the E2F-cyclin A complex. We find that the HPV-16 E7 protein associates very efficiently with the E2F-cyclin A complex. This association is dependent on the sequences that are also necessary for the transforming activity of E7. Moreover, the E7 protein of a low-risk HPV (type 6b) is much less efficient in binding to the E2F-cyclin A complex compared with that of the high-risk type. We also find that the E2F-cyclin A complex remains endogenously associated with the E7 protein in extracts of Caski cells, which express high levels of HPV-16 E7 protein. Finally, we have extensively purified the E2F-cyclin A complex from mouse L-cell extracts and show that, in cell extracts, the E2F-cyclin A complex remains associated with other cellular proteins.


Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Ciclinas/metabolismo , Proteínas de Ligação a DNA , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sequência de Bases , DNA , Fatores de Transcrição E2F , Células L , Camundongos , Dados de Sequência Molecular , Proteínas E7 de Papillomavirus , Reação em Cadeia da Polimerase , Proteína 1 de Ligação ao Retinoblastoma , Fase S , Fator de Transcrição DP1
9.
Mol Cell Biol ; 15(10): 5444-52, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7565695

RESUMO

The retinoblastoma-related protein p107 has been shown to be a regulator of the transcription factor E2F. p107 associates with E2F via its pocket region and represses E2F-dependent transcription. In this study, we provide evidence for a novel interaction between p107 and the transcription factor Sp1. We show that p107 can be found endogenously associated with Sp1 in the extracts of several different cell lines. Moreover, in transient transfection assays, expression of p107 represses Sp1-dependent transcription. This repression of Sp1-dependent transcription does not require the DNA-binding domain of Sp1. Transcription driven by a chimeric protein containing the Ga14 DNA-binding domain and the Sp1 activation domains is inhibited by p107. Interestingly, unlike the repression of E2F-dependent transcription, the repression of Sp1-dependent transcription does not depend on an intact pocket region. We show that distinct regions of p107 are involved in the control of Sp1 and E2F.


Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Proteínas Nucleares/metabolismo , Proteínas Repressoras/metabolismo , Fator de Transcrição Sp1/metabolismo , Fatores de Transcrição/fisiologia , Animais , Anticorpos Monoclonais , Sequência de Bases , Reações Cruzadas , DNA/metabolismo , Fatores de Transcrição E2F , Células L , Camundongos , Dados de Sequência Molecular , Proteínas Nucleares/genética , Fragmentos de Peptídeos , Testes de Precipitina , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/metabolismo , Proteína 1 de Ligação ao Retinoblastoma , Proteína p107 Retinoblastoma-Like , Fator de Transcrição Sp1/genética , Fator de Transcrição DP1 , Transcrição Gênica/fisiologia
10.
Mol Cell Biol ; 12(10): 4327-33, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1406625

RESUMO

Several reports have indicated that the product of the retinoblastoma gene (Rb) complexes with the transcription factor E2F. We present evidence that the DNA-binding of the Rb-E2F complex involves another cellular factor. Addition of Rb to purified preparations of E2F does not generate an Rb-E2F complex that can bind DNA, and in fact, we see an inhibition of the DNA-binding ability of E2F. On the other hand, addition of Rb to cruder preparations of E2F results in the formation of an Rb-E2F complex (E2Fr) that can bind DNA and produces a distinct complex in gel retardation assays. We have identified and purified a 60-kDa protein that allows the Rb-E2F complex to bind DNA, and we show that this 60-kDa protein exerts its effect by directly interacting with Rb.


Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Proteínas/metabolismo , Proteína do Retinoblastoma/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sequência de Bases , Western Blotting , DNA/metabolismo , Fatores de Transcrição E2F , Eletroforese em Gel de Poliacrilamida , Células HeLa , Humanos , Células L , Camundongos , Dados de Sequência Molecular , Ligação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína 1 de Ligação ao Retinoblastoma , Fator de Transcrição DP1
11.
Mol Cell Biol ; 20(5): 1571-82, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10669735

RESUMO

The inhibitor of kappa B alpha (IkappaBalpha) protein is able to shuttle between the cytoplasm and the nucleus. We have utilized a combination of in vivo and in vitro approaches to provide mechanistic insight into nucleocytoplasmic shuttling by IkappaBalpha. IkappaBalpha contains multiple functional domains that contribute to shuttling of IkappaBalpha between the cytoplasm and the nucleus. Nuclear import of IkappaBalpha is mediated by the central ankyrin repeat domain. Similar to previously described nuclear import pathways, nuclear import of IkappaBalpha is temperature and ATP dependent and is blocked by a dominant-negative mutant of importin beta. However, in contrast to classical nuclear import pathways, nuclear import of IkappaBalpha is independent of soluble cytosolic factors and is not blocked by the dominant-negative RanQ69L protein. Nuclear export of IkappaBalpha is mediated by an N-terminal nuclear export sequence. Nuclear export of IkappaBalpha requires the CRM1 nuclear export receptor and is blocked by the dominant-negative RanQ69L protein. Our results are consistent with a model in which nuclear import of IkappaBalpha is mediated through direct interactions with components of the nuclear pore complex, while nuclear export of IkappaBalpha is mediated via a CRM1-dependent pathway.


Assuntos
Núcleo Celular/metabolismo , Proteínas I-kappa B/metabolismo , Transdução de Sinais , Proteína ran de Ligação ao GTP/metabolismo , Transporte Biológico , Células HeLa , Humanos
12.
Mol Cell Biol ; 20(18): 6646-58, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10958662

RESUMO

In yeast, HOP1 and RED1 are required during meiosis for proper chromosome segregation and the consequent formation of viable spores. Mutations in either HOP1 or RED1 create unique as well as overlapping phenotypes, indicating that the two proteins act alone as well as in concert with each other. To understand which meiotic processes specifically require Red1p-Hop1p hetero-oligomers, a novel genetic screen was used to identify a single-point mutation of RED1, red1-K348E, that separates Hop1p binding from Red1p homo-oligomerization. The Red1-K348E protein is stable, phosphorylated in a manner equivalent to Red1p, and undergoes efficient homo-oligomerization; however, its ability to interact with Hop1p both by two-hybrid and coimmunoprecipitation assays is greatly reduced. Overexpression of HOP1 specifically suppresses red1-K348E, supporting the idea that the only defect in the protein is a reduced affinity for Hop1p. red1-K348E mutants exhibit reduced levels of crossing over and spore viability and fail to undergo chromosome synapsis, thereby implicating a role for Red1p-Hop1p hetero-oligomers in these processes. Furthermore, red1-K348E suppresses the sae2/com1 defects in meiotic progression and sporulation, indicating a previously unknown role for HOP1 in the meiotic recombination checkpoint.


Assuntos
Segregação de Cromossomos/fisiologia , Cromossomos Fúngicos/fisiologia , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Meiose/fisiologia , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiologia , Transdução de Sinais/fisiologia , Alelos , Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Segregação de Cromossomos/genética , Troca Genética , Endonucleases , Proteínas Fúngicas/genética , Deleção de Genes , Expressão Gênica , Mutagênese , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Fenótipo , Recombinação Genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Esporos Fúngicos/fisiologia
13.
Mol Cell Biol ; 16(3): 737-44, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8622674

RESUMO

In nonproliferating or growth-arrested cells, the transcription factor E2F remains bound to the retinoblastoma-related protein p130. Accumulation of this E2F-p130 complex correlates with an arrest of the cell cycle progression. Progression through G1 phase is associated with a cyclin-dependent binding of the cyclin-dependent kinase cdk2 to the E2F-p130 complex. By fractionating mouse L-cell extracts, we have obtained a partially purified preparation of the E2F-p130 complex that also contains cdk2. Incubation of this complex with recombinant p21 results in a disruption of the interaction between cdk2 and the E2F-p130 complex in extracts of a cell line that expresses a temperature-sensitive mutant of p53. Incubation at the permissive temperature (32 degrees C) results in an induction of p21 synthesis. An increase in the level of p21 in these cells correlates with a loss of cdk2 from the cdk2-containing E2F-p130 complex. We also show that the expression of a reporter gene containing E2F sites in the promoter region is reduced by the coexpression of p21. Since p21 is believed to be a mediator of p53, we speculated that the p21-mediated disruption of the cdk2-containing E2F-p130 complex plays a role in the growth suppression function of p53.


Assuntos
Quinases relacionadas a CDC2 e CDC28 , Proteínas de Transporte , Proteínas de Ciclo Celular , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/metabolismo , Proteínas de Ligação a DNA , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas , Fatores de Transcrição/metabolismo , Animais , Ciclo Celular , Linhagem Celular , Quinase 2 Dependente de Ciclina , Inibidor de Quinase Dependente de Ciclina p21 , Fatores de Transcrição E2F , Fase G1 , Regulação da Expressão Gênica , Camundongos , Mutação , Proteínas Recombinantes/metabolismo , Proteína 1 de Ligação ao Retinoblastoma , Proteína p130 Retinoblastoma-Like , Fator de Transcrição DP1 , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
15.
Carbohydr Polym ; 138: 215-21, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26794755

RESUMO

In this existing experimental work, water soluble PDP polysaccharides were secluded from Pithecellobium dulce (Roxb.) Benth. seeds. The physicochemical properties were analyzed in terms of swelling power, solubility, pH and water holding capacity. Micromeretic studies proved the polysaccharide may be used a potential pharmaceutical adjuvant. The polysaccharide was characterized by FT-IR, SEM, TGA and NMR techniques. Methylation analysis confirmed that the polysaccharide is composed of Arabinose (Araf) units. The chemical shifts of anomeric proton region were found in the region of 4.4-5.5ppm. Thermogravimetric analysis showed that PDP polysaccharide was thermally stable. The in vitro antioxidant capacities of the polysaccharide were investigated in terms of scavenging of hydroxyl radicals, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals, hydrogen peroxide (H2O2) and reducing power assay. The polysaccharide fractions showed activity in a concentration dependent manner which was comparable to the standard, ascorbic acid.


Assuntos
Fabaceae/metabolismo , Polissacarídeos/química , Água/química , Sequestradores de Radicais Livres/química , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Microscopia Eletrônica de Varredura , Sementes/metabolismo , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
16.
Indian J Nephrol ; 26(4): 244-51, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27512295

RESUMO

There is no published study from India on hepatitis C virus (HCV) treatment in dialysis patients. Patients on dialysis with HCV infection treated with pegylated interferon (Peg-INF) monotherapy were studied. All patients were subjected to HCV-polymerase chain reaction, viral load, genotype, and liver biopsy. Quantitative HCV-RNA was performed monthly. Patients with genotype 1 and 4 were given 12 month therapy while those with genotypes 2 and 3 were given 6 months therapy. Response was classified as per standard criteria of rapid virological response (RVR), early virological response (EVR), end of treatment response (ETR), and sustained virological response (SVR). A total of 85 patients were treated. Mean age was 35.2 ± 10.5 (range 15-67) years, and 77.6% were males. HCV genotypes were 1 in 40.9%, 2 in 12%, 3 in 36.1%, 4 in 3.6%, and others in 7.2%. Mean viral load was 10(6) copies/mL. Mean liver biopsy grade was 4 ± 1.7 and stage 0.8 ± 0.8. Mean time from diagnosis of HCV infection and the treatment start was 10.7 ± 14.3 months. One patient died of unrelated illness, one was lost to follow-up, and three could not sustain treatment due to cost. Forty-three of the 80 (54%) patients had RVR while 49 (61%) patients had EVR and ETR. There was no difference in term of RVR related to genotype. Fifty -four percentage had SVR. Mild flu-like symptoms were seen in all patients. Sixty-four (80%) patients required increase in erythropoietin doses. Twenty-eight (35%) patients developed leukopenia (three treatment-limiting) and 16 (20%) developed thrombocytopenia (one treatment-limiting). Five patients developed tuberculosis, five bacterial pneumonia, and one bacterial knee monoarthritis. None of the patients developed depression. Our study concludes that Peg-INF monotherapy resulted in 54% RVR and SVR in dialysis patients with HCV infection. Therapy was well-tolerated with minimal side effects. There was no effect of viral genotype on response to therapy.

17.
Indian J Nephrol ; 26(3): 212-5, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27194838

RESUMO

Post transplant lymphoproliferative disorder include a spectrum of conditions occurring in immunosuppressed post transplant recipients, lymphoma being the most ominous. (18)F-fludeoxyglucose positron emission tomography with computed tomography CT) is the current imaging gold standard for lymphoma imaging as it allows both morphological and functional assessment. CT and/or conventional magnetic resonance imaging (MRI) are used for morphological evaluation in transplant recipients. Integrating diffusion weighted imaging with apparent diffusion coefficient analysis in MRI protocol enhances its sensitivity and may prove invaluable in response assessment in transplant recipients.

18.
Oncogene ; 20(34): 4740-9, 2001 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-11498796

RESUMO

High-risk human papillomaviruses (HPVs) are etiologically linked to human cervical and oral cancers. The E6 and E7 oncoproteins encoded by HPV target host cell tumor suppressor proteins. E6 induces proteolysis of p53 through the ubiquitin-proteasome pathway. Recent studies showed that overexpression of E7 caused proteolytic degradation of the tumor suppressor Rb. However, unlike p53, Rb is not regulated by proteolysis in normal cells. In addition, it was unclear whether in its natural context E7 regulates Rb through the ubiquitin-proteasome pathway. Therefore, we sought to determine whether Rb is regulated by the ubiquitin-proteasome pathway in HPV-containing tumor cells. We carried out a detailed analysis in Caski cells, that are derived from HPV-containing cervical cancer tissues. Studies with various protease inhibitors revealed that Rb is regulated specifically by the ubiquitin-proteasome pathway in HPV-containing cervical tumor cells. Several inhibitors of the 26S proteasome significantly increased the level of Rb in the Caski cells. Rb controls cell growth by forming complexes with the E2F-family transcription factors. Surprisingly, in spite of a significant accumulation of the hypophosphorylated form of Rb, no Rb/E2F complex was detectable in the proteasome inhibitor treated cells. Further analysis revealed that there was an increased accumulation of the E7 oncoprotein. We showed that the proteasome inhibitors simultaneously blocked the proteolysis of E7 and Rb, suggesting that E7 is also regulated by the ubiquitin-dependent proteolysis in cervical cancer cells. Taken together, this study suggests that targeted inhibition of Rb proteolysis will be required for restoring Rb function in HPV-containing cervical cancer cells.


Assuntos
Carcinoma/virologia , Proteínas de Ciclo Celular , Cisteína Endopeptidases/fisiologia , Proteínas de Ligação a DNA , Complexos Multienzimáticos/fisiologia , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae/patogenicidade , Proteína do Retinoblastoma/metabolismo , Ubiquitinas/metabolismo , Neoplasias do Colo do Útero/virologia , Carcinoma/metabolismo , Linhagem Celular Transformada , Transformação Celular Viral , Inibidores de Cisteína Proteinase/farmacologia , Fatores de Transcrição E2F , Feminino , Humanos , Leupeptinas/farmacologia , Complexos Multienzimáticos/antagonistas & inibidores , Proteínas E7 de Papillomavirus , Fosforilação , Complexo de Endopeptidases do Proteassoma , Fatores de Transcrição/metabolismo , Neoplasias do Colo do Útero/metabolismo
19.
Biochim Biophys Acta ; 1041(1): 9-13, 1990 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-2121280

RESUMO

Extracts from ammonium-grown phototrophic cultures of Phormidium uncinatum exhibited a catalytic and stoichiometric formation of nitrite and ammonia from hydrogen peroxide and hydroxylamine. This reaction was due to a novel enzyme (referred to as hydroxylamine dismutase), which was bound to the heavier thylakoid membranes. The enzyme was solubilized from the membranes by detergent treatment and further purified by ion-exchange chromatography. On the basis of inhibitor studies, the involvement of metal ions and sulfhydryl groups in the characteristic reaction is suggested.


Assuntos
Cianobactérias/enzimologia , Hidroxilaminas/metabolismo , Oxirredutases/metabolismo , Amônia , Membrana Celular/enzimologia , Cromatografia por Troca Iônica , Hidroxilamina , Cinética , Oxirredutases/isolamento & purificação , Solubilidade , Água
20.
Indian J Public Health ; 49(4): 256-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16479915

RESUMO

This study was carried out among the Private Allopathic Medical Practitioners (PMPs) at Khardah Municipal area (West Bengal) to find out their perception & practice about management protocol of diseases like acute respiratory infections and diarrhoel diseases in children, malaria and tuberculosis. Data was collected by interviewing the PMPs with pre-designed open-ended questionnaire. It was supplemented by analysing sample prescriptions of the same diseases. The study revealed that PMPs knowledge and practice were not at par with national guidelines. The need for periodic sensitization of PMPs regarding national disease control programme was emphasized.


Assuntos
Doenças Transmissíveis/terapia , Conhecimentos, Atitudes e Prática em Saúde , Médicos , Padrões de Prática Médica , Criança , Proteção da Criança , Controle de Doenças Transmissíveis , Estudos Transversais , Humanos , Índia , Guias de Prática Clínica como Assunto , Setor Privado
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