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1.
Clin Oral Investig ; 22(3): 1337-1343, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28988345

RESUMO

OBJECTIVE: This multicenter randomized controlled clinical trial aimed to compare the outcomes of stepwise excavation (SW) and partial caries removal (PCR) regarding the maintenance of pulp vitality in deep caries lesions over 5 years. METHODS: At baseline, 299 permanent molars with deep caries lesions were randomly assigned to control or test groups. The control group received the stepwise excavation treatment (SW), while the test group received partial caries removal from the pulpal wall followed by restoration in a single session (PCR). Treatments were conducted in two centers located in the cities of Porto Alegre (South Brazil) and Brasília (Midwest Brazil). Survival analysis was performed to compare PCR and SW over time (Weibull regression models). The primary outcome of this study was pulp vitality, determined by the combination of the following characteristics: positive response to cold test, negative response to percussion, absence of spontaneous pain, and absence of periapical lesion (radiographic examination). RESULTS: This 5-year study includes data pertaining to 229 teeth: 121 teeth actually examined at the 5-year appointment, and 108 teeth contributed with data collected in previous follow-ups (18 months or 3 years). Survival analysis showed success rates of 80% in PCR group and 56% in SW group (p < 0.001). Failure was significantly associated with treatment [PCR, HR=0.38; 95%CI=0.23-0.63)] and region [South, HR=2.22; 95%CI=1.21-4.08]. CONCLUSION: PCR significantly reduced the occurrence of pulp necrosis when compared with SW. CLINICAL RELEVANCE: This study supports the PCR as a single-visit technique to manage deep caries lesions in permanent teeth.


Assuntos
Cárie Dentária/terapia , Necrose da Polpa Dentária/prevenção & controle , Restauração Dentária Permanente/métodos , Adolescente , Adulto , Dentição Permanente , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dente Molar , Resultado do Tratamento
2.
Science ; 270(5240): 1360-2, 1995 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-7481824

RESUMO

Immune evasion by the human immunodeficiency virus (HIV) is unexplained but may involve the mutation of viral antigens. When cytotoxic T lymphocytes engaged CD4-positive cells that were acutely infected with HIV bearing natural variant epitopes in reverse transcriptase, substantial inhibition of specific antiviral lysis was observed. Mutant viruses capable of these transactive effects could facilitate the persistence of a broad range of HIV variants in the face of an active and specific immune response.


Assuntos
Citotoxicidade Imunológica , Antígenos HIV/imunologia , HIV-1/imunologia , Tolerância Imunológica , DNA Polimerase Dirigida por RNA/imunologia , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Variação Antigênica , Sequência de Bases , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Linhagem Celular , Epitopos/genética , Antígenos HIV/genética , Transcriptase Reversa do HIV , HIV-1/enzimologia , HIV-1/genética , Antígeno HLA-B8/imunologia , Humanos , Dados de Sequência Molecular , DNA Polimerase Dirigida por RNA/genética , Receptores de Antígenos de Linfócitos T/imunologia
3.
World J Microbiol Biotechnol ; 10(2): 154-8, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24420937

RESUMO

Polyclonal antisera, produced against whole cells of Thiobacillus thiooxidans, T. ferrooxidans and Leptospirillum ferrooxidans, gave highly specific reactions when cross-reacted with 23 strains of acidophilic bacteria using an immunofluorescence (IF) staining technique. Strains of identical serotype exhibited maximum cross-reaction whereas strains of different serotype reacted only weakly. Lipopolysaccharides (LPS) examined by SDS-PAGE showed different, serotype-specific migration patterns indicating their rough or smooth character. LPS patterns may therefore be used for serological classification of acidophilic bacteria. Surface antigens of four strains were identified by immunoblot staining; LPS and some proteins were antigenic determinants with LPS the most specific.

4.
Nephrol Dial Transplant ; 5(10): 860-7, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2128381

RESUMO

In rats with normal renal function the intestinal absorption of aluminium appears to be partly vitamin D dependent. To further characterise the similarities between the absorption of aluminium and calcium we investigated the effects of dihydroxylated vitamin D metabolites, prednisolone, and chloroquine (CQ) in Sprague-Dawley rats with normal or reduced renal function. The latter agents interfere with lysosomal functions and have been reported to reduce the intestinal absorption of calcium, whereas vitamin D metabolites may stimulate the absorption of both aluminium and calcium. To assess the intestinal absorption of aluminium we monitored urinary aluminium excretion and serum aluminium concentrations following an oral load of 410 mumol aluminium. Calcium absorption was calculated from the differences between an orally administered dose of 45calcium and faecal excretion. In vitamin-D-deficient rats cholecalciferol and calcitriol augmented urinary aluminium excretion to a similar degree subsequent to an oral load whereas 24R,25(OH)2D3 was without an apparent effect. In vitamin-D-replete rats with normal renal function CQ (225 mg/kg i.p.; 3 days) as well as prednisolone (25 mg/kg; 7 days) significantly reduced calcium absorption (% dose) (CQ: 39 +/- 5%, prednisolone: 42 +/- 3%, control: 58 +/- 11%). In contrast neither drug reduced urinary aluminium excretion (CQ: 519 +/- 92, prednisolone: 494 +/- 137, control: 469 +/- 187 nmol/5 days) or the postload increase in serum aluminium following oral exposure. When aluminium was administered intravenously recovery of aluminium was comparable between treatment groups and controls.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Alumínio/farmacocinética , Cálcio/farmacocinética , Absorção Intestinal , Animais , Cloroquina/farmacologia , Absorção Intestinal/efeitos dos fármacos , Masculino , Prednisolona/farmacologia , Ratos , Ratos Endogâmicos , Vitamina D/metabolismo , Vitamina D/farmacologia
5.
J Virol ; 68(4): 2313-9, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8139016

RESUMO

The mouse mammary tumor virus gag-pro transframe protein (p30) contains the nucleocapsid protein domain derived from the 3' end of gag, fused to 154 residues encoded by the 5' region of the pro open reading frame. The DNA coding for p30 was cloned into the plasmid pALTER-1, and an additional nucleotide was inserted by site-directed mutagenesis to allow the read-through from the gag into the pro open reading frame. The obtained insert was then cloned into pGEX-2T, a plasmid containing the glutathione S-transferase gene of Schistosoma japonicum and a nucleotide sequence encoding for a thrombin cleavage site. The chimeric protein (GST-p30) was isolated by affinity chromatography on a glutathione-Sepharose 4B column, and after thrombin treatment, the excised p30 was further purified on a single-stranded DNA-agarose column. This protein showed dUTPase activity, with only negligible cleavage of dATP, dGTP, dCTP, dTTP, or UTP. Its apparent Km for dUTP was 28 microM. The enzyme was inhibited by EDTA, but its effect could be reversed by Mg2+ and other divalent cations. dUTPase activity was also detected in purified mouse mammary tumor virus, and p30 was the only protein recognized by antibodies directed towards the carboxyl-terminal sequence of the dUTPase coding region.


Assuntos
Vírus do Tumor Mamário do Camundongo/enzimologia , Pirofosfatases/metabolismo , Proteínas do Core Viral/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Cátions Bivalentes/farmacologia , Quelantes/farmacologia , Clonagem Molecular , Escherichia coli/genética , Expressão Gênica , Produtos do Gene gag/genética , Produtos do Gene gag/isolamento & purificação , Produtos do Gene gag/metabolismo , Produtos do Gene pol/genética , Produtos do Gene pol/isolamento & purificação , Produtos do Gene pol/metabolismo , Dados de Sequência Molecular , Pirofosfatases/efeitos dos fármacos , Pirofosfatases/genética , Pirofosfatases/isolamento & purificação , Fases de Leitura , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Análise de Sequência , Especificidade por Substrato , Proteínas do Core Viral/efeitos dos fármacos , Proteínas do Core Viral/genética , Proteínas do Core Viral/isolamento & purificação
7.
Nature ; 369(6479): 403-7, 1994 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-7515165

RESUMO

Most asymptomatic individuals infected with HIV-1 have a cytotoxic T lymphocyte (CTL) response to the virus Gag proteins which can be demonstrated in vitro. Epitopes have been mapped in p17 Gag and p24 Gag restricted by HLA-B8 (p17-3 and p24-13) and -B27 (p24-14). Viruses isolated from patients who make CTL responses to these peptides vary within the genetic sequences encoding these epitopes and some mutations lead to reduction in killing activity in vitro. This was attributed to either failure of the variant epitope to bind major histocompatibility complex class I or failure of T-cell receptors to bind the presented peptide. But peptide variants of class I-restricted epitopes cause 'antagonism', that is, the presence of a variant epitope (in the form of peptide) inhibits normal lysis of targets presenting the original epitope. This mirrors similar findings in class II-restricted systems. Here we report that naturally occurring variant forms of p17-3, p24-13 and p24-14 may cause antagonism of CTL lines derived from the same individuals. The effect is present if the epitopes are derived from synthetic peptides and when they are processed from full-length proteins expressed by either recombinant vaccinia constructs or replicating HIV.


Assuntos
Produtos do Gene gag/imunologia , HIV-1/imunologia , Receptores de Antígenos de Linfócitos T/antagonistas & inibidores , Linfócitos T Citotóxicos/imunologia , Proteínas Virais , Sequência de Aminoácidos , Linhagem Celular , Epitopos/genética , Epitopos/imunologia , Produtos do Gene gag/genética , Variação Genética , Antígenos HIV/genética , Antígenos HIV/imunologia , Proteína do Núcleo p24 do HIV/genética , Proteína do Núcleo p24 do HIV/imunologia , Antígeno HLA-B8/imunologia , Humanos , Dados de Sequência Molecular , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Vaccinia virus/genética , Produtos do Gene gag do Vírus da Imunodeficiência Humana
8.
Nature ; 375(6532): 606-11, 1995 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-7791879

RESUMO

A typical protein antigen contains several epitopes that can be recognized by cytotoxic T lymphocytes (CTL), but in a characteristic antiviral immune response in vivo, CTL recognize only a small number of these potential epitopes, sometimes only one, this phenomenon is known as immunodominance. Antigenic variation within CTL epitopes has been demonstrated for the human immunodeficiency virus HIV-1 (ref. 11) and other viruses and such 'antigenic escape' may be responsible for viral persistence. Here we develop a new mathematical model that deals with the interaction between CTL and multiple epitopes of a genetically variable pathogen, and show that the nonlinear competition among CTL responses against different epitopes can explain immunodominance. This model suggests that an antigenically homogeneous pathogen population tends to induce a dominant response against a single epitope, whereas a heterogeneous pathogen population can stimulate complicated fluctuating responses against multiple epitopes. Antigenic variation in the immunodominant epitope can shift responses to weaker epitopes and thereby reduce immunological control of the pathogen population. These ideas are consistent with detailed longitudinal studies of CTL responses in HIV-1 infected patients. For vaccine design, the model suggests that the major response should be directed against conserved epitopes even if they are subdominant.


Assuntos
Variação Antigênica , Antígenos HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Epitopos Imunodominantes/imunologia , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Infecções por HIV/complicações , Antígeno HLA-B27/imunologia , Antígeno HLA-B8/imunologia , Hemofilia A/complicações , Hemofilia A/imunologia , Humanos , Modelos Imunológicos , Dados de Sequência Molecular
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