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1.
J Infect Dis ; 221(10): 1607-1611, 2020 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-31840184

RESUMO

BACKGROUND: This study was conducted to examine patient characteristics associated with antiretroviral therapy (ART) reinitiation in Medicaid enrollees. METHODS: This is a retrospective cohort study that uses Cox proportional hazard regression to examine the association between person-level characteristics and time from ART discontinuation to the subsequent reinitiation within 18 months. RESULTS: There were 45 409 patients who discontinued ART, and 44% failed to reinitiate. More outpatient visits (3+ vs 0 outpatient visits: adjusted hazard ratio (adjHR), 1.56; 99% confidence interval [CI], 1.45-1.67) and hospitalization (adjHR, 1.18; 99% CI,1.16-1.20) during follow-up were associated with reinitiation. CONCLUSIONS: Failure to reinitiate ART within 18 months was common in this sample. Care engagement was associated with greater ART reinitiation.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Cooperação do Paciente , Adulto , Estudos de Coortes , Feminino , HIV-1 , Humanos , Masculino , Medicaid , Pessoa de Meia-Idade , Estudos Retrospectivos , Estados Unidos
2.
AIDS Behav ; 21(2): 470-480, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27714525

RESUMO

Questions remain regarding optimal timeframes for asking about adherence in clinical care. We compared 4-, 7-, 14-, 30-, and 60-day timeframe missed dose items with viral load levels among 1099 patients on antiretroviral therapy in routine care. We conducted logistic and linear regression analyses examining associations between different timeframes and viral load using Bayesian model averaging (BMA). We conducted sensitivity analyses with subgroups at increased risk for suboptimal adherence (e.g. patients with depression, substance use). The 14-day timeframe had the largest mean difference in adherence levels among those with detectable and undetectable viral loads. BMA estimates suggested the 14-day timeframe was strongest overall and for most subgroups although findings differed somewhat for hazardous alcohol users and those with current depression. Adherence measured by all missed dose timeframes correlated with viral load. Adherence calculated from intermediate timeframes (e.g. 14-day) appeared best able to capture adherence behavior as measured by viral load.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Adesão à Medicação , Carga Viral , Adulto , Transtornos Relacionados ao Uso de Álcool/epidemiologia , Terapia Antirretroviral de Alta Atividade , Teorema de Bayes , Comorbidade , Transtorno Depressivo/epidemiologia , Feminino , Infecções por HIV/sangue , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , Humanos , Modelos Lineares , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Questionário de Saúde do Paciente , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Inquéritos e Questionários , Fatores de Tempo
3.
AIDS Behav ; 19(9): 1666-75, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25711300

RESUMO

Intended conception likely contributes to a significant proportion of new HIV infections in South Africa. Safer conception strategies require healthcare provider-client communication about fertility intentions, periconception risks, and options to modify those risks. We conducted in-depth interviews with 35 HIV-infected men and women accessing care in South Africa to explore barriers and promoters to patient-provider communication around fertility desires and intentions. Few participants had discussed personal fertility goals with providers. Discussions about pregnancy focused on maternal and child health, not sexual HIV transmission; no participants had received tailored safer conception advice. Although participants welcomed safer conception counseling, barriers to client-initiated discussions included narrowly focused prevention messages and perceptions that periconception transmission risk is not modifiable. Supporting providers to assess clients' fertility intentions and offer appropriate advice, and public health campaigns that address sexual HIV transmission in the context of conception may improve awareness of and access to safer conception strategies.


Assuntos
Preservativos/estatística & dados numéricos , Aconselhamento , Fertilização , Infecções por HIV/prevenção & controle , Intenção , Relações Profissional-Paciente , Adulto , Feminino , Infecções por HIV/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde/psicologia , Humanos , Masculino , Motivação , Gravidez , Complicações Infecciosas na Gravidez/prevenção & controle , Parceiros Sexuais , África do Sul
4.
Intern Med J ; 44(10): 950-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25302718

RESUMO

Multiple sclerosis was without effective disease-modifying therapy for many years. The introduction of the injectable therapies (interferon and glatiramer acetate) some 20 years ago was considered a major advance. Recent years have heralded a revolution in treatment options with the introduction of intravenous natalizumab and, even more recently, three oral agents. We are currently in a period of determining the best use of these therapies to ensure prevention of disease progression while maintaining patient safety. Despite these new treatments, there are still many patients living with disability as a result of multiple sclerosis and significant attention must be given to symptomatic management.


Assuntos
Administração Intravenosa , Administração Oral , Imunossupressores , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Alemtuzumab , Anticorpos Monoclonais Humanizados , Crotonatos , Fumarato de Dimetilo , Progressão da Doença , Esquema de Medicação , Cloridrato de Fingolimode , Fumaratos , Humanos , Hidroxibutiratos , Imunossupressores/administração & dosagem , Mitoxantrona , Esclerose Múltipla Recidivante-Remitente/fisiopatologia , Natalizumab , Nitrilas , Propilenoglicóis , Medição de Risco , Esfingosina/análogos & derivados , Toluidinas
5.
AIDS Behav ; 17(1): 307-18, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23108721

RESUMO

The self-rating scale item (SRSI) is a single-item self-report adherence measure that uses adjectives in a 5-point Likert scale, from "very poor" to "excellent," to describe medication adherence over the past 4 weeks. This study investigated the SRSI in 2,399 HIV-infected patients in routine care at two outpatient primary HIV clinics. Correlations between the SRSI and four commonly used adherence items ranged from 0.37 to 0.64. Correlations of adherence barriers, such as depression and substance use, were comparable across all adherence items. General estimating equations suggested the SRSI is as good as or better than other adherence items (p's <0.001 vs. <0.001-0.99) at predicting adherence-related clinical outcomes, such as HIV viral load and CD4(+) cell count. These results and the SRSI's low patient burden suggest its routine use could be helpful for assessing adherence in clinical care and should be more widespread, particularly where more complex instruments may be impractical.


Assuntos
Antirretrovirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , Adesão à Medicação/estatística & dados numéricos , Autorrelato , Inquéritos e Questionários , Adulto , Consumo de Bebidas Alcoólicas/psicologia , Contagem de Linfócito CD4 , Depressão/complicações , Depressão/psicologia , Feminino , Infecções por HIV/psicologia , Infecções por HIV/virologia , Humanos , Entrevistas como Assunto , Masculino , Adesão à Medicação/psicologia , Pessoa de Meia-Idade , Medição da Dor , Testes Psicológicos , Sensibilidade e Especificidade , Fatores Socioeconômicos , Abuso de Substâncias por Via Intravenosa/complicações , Abuso de Substâncias por Via Intravenosa/psicologia , Resultado do Tratamento , Carga Viral
6.
Artigo em Inglês | MEDLINE | ID: mdl-22869134

RESUMO

The lysosomal α-mannosidases are class II mannosidases that belong to glycoside hydrolase family 38 and play an important role in the degradation of asparagine-linked carbohydrates of glycoproteins. Based on peptide similarity to human and bovine lysosomal mannosidase (LM), recombinant α-mannosidase from Drosophila melanogaster (dLM408) was cloned and heterologously expressed in Pichia pastoris. The recombinant form of dLM408 designed for structural analysis lacks the transmembrane domain and was crystallized using standard vapour-diffusion and counter-diffusion techniques. The crystals grew as flat plates and as tetragonal bipyramids, respectively. The plate-shaped crystals exhibited the symmetry of space group P2(1)2(1)2(1) and diffracted to a minimum d-spacing of 3.5 Å.


Assuntos
Drosophila melanogaster/enzimologia , alfa-Manosidase/química , Animais , Cristalografia por Raios X , Expressão Gênica , alfa-Manosidase/genética , alfa-Manosidase/isolamento & purificação
7.
BMJ Open ; 7(2): e013496, 2017 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-28188154

RESUMO

INTRODUCTION: Medication adherence is fundamental to achieving optimal patient outcomes. Reporting research on medication adherence suffers from some issues-including conceptualisation, measurement and data analysis-that thwart its advancement. Using the ABC taxonomy for medication adherence as the conceptual basis, a steering committee of members of the European Society for Patient Adherence, COMpliance, and Persistence (ESPACOMP) launched an initiative to develop ESPACOMP Medication Adherence Reporting Guidelines (EMERGE). This paper is a protocol for a Delphi study that aims to build consensus among a group of topic experts regarding an item list that will support developing EMERGE. METHODS AND ANALYSIS: This study uses a reactive-Delphi design where a group of topic experts will be asked to rate the relevance and clarity of an initial list of items, in addition to suggesting further items and/or modifications of the initial items. The initial item list, generated by the EMERGE steering committee through a structured process, consists of 26 items distributed in 2 sections: 4 items representing the taxonomy-based minimum reporting criteria, and 22 items organised according to the common reporting sections. A purposive sample of experts will be selected from relevant disciplines and diverse geographical locations. Consensus will be achieved through predefined decision rules to keep, delete or modify the items. An iterative process of online survey rounds will be carried out until consensus is reached. ETHICS AND DISSEMINATION: An ethics approval was not required for the study according to the Swiss federal act on research involving human beings. The participating experts will be asked to give an informed consent. The results of this Delphi study will feed into EMERGE, which will be disseminated through peer-reviewed publications and presentations at conferences. Additionally, the steering committee will encourage their endorsement by registering the guidelines at the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) network and other relevant organisations.


Assuntos
Adesão à Medicação , Relatório de Pesquisa/normas , Consenso , Técnica Delphi , Europa (Continente) , Humanos , Sociedades Médicas
8.
Burns ; 32(5): 602-4, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16720080

RESUMO

During the period 20 February 1970-19 February 2000, burns resulting in squamous cell carcinoma of the skin were documented by using a histopathology data pool of surgical specimens kept by the author as regards his Ibos ethnic group in Nigeria, West Africa. There were 21 cases. The males outnumbered the females in the ratio of 3:1. The youngest patient was aged 8 years and the oldest 75 years (mean age 39 years). Most of the antecedent injuries occurred during childhood. The two etiologic agents of albinism and burns were combined in one patient while another rarity was the presentation of the cancer within keloids. In conclusion, in dark skinned races, research should be directed on the comparative role of burns in predisposing to squamous cell carcinoma in individuals whose skin is compromised by either albinism or keloids.


Assuntos
Queimaduras/etnologia , Cicatriz/etnologia , Neoplasias Cutâneas/etnologia , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nigéria/etnologia
9.
Cancer Res ; 38(8): 2519-22, 1978 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-667847

RESUMO

A new isoenzyme of alkaline phosphatase (EC 3.1.3.1) has been reported to occur in sera from patients with lymphoproliferative diseases. This enzyme is characterized by an inability to hydrolyze cysteamine S-phosphate. We find that the 5,5'-dithobis(2-nitrobenzoic acid)-coupled assay method for cysteamine S-phosphate hydrolysis is not suitable for serum, and we were unable to confirm the existence of this isoenzyme in serum by this assay method. We were unable to detect to detect this new isoenzyme by polyacrylamide gel electrophoresis with activity stains or by the reported high sensitivity of this enzyme to inhibition by cysteamine S-phosphate when p-nitrophenyl phosphate is the substrate. We were also unable to confirm reports of a unique inhibitor of normal alkaline phosphatase in the serum of patients with infectious mononucleosis.


Assuntos
Fosfatase Alcalina/sangue , Mononucleose Infecciosa/enzimologia , Isoenzimas/sangue , Leucemia/enzimologia , Linfoma/enzimologia , Fosfatase Alcalina/antagonistas & inibidores , Cisteamina/análogos & derivados , Eletroforese em Gel de Poliacrilamida , Inibidores Enzimáticos/sangue , Humanos , Mononucleose Infecciosa/sangue , Isoenzimas/antagonistas & inibidores , Compostos Organofosforados
10.
Biochim Biophys Acta ; 523(1): 101-8, 1978 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-204352

RESUMO

1. In order to elucidate some features of the mechanism of the acceleration of methanesulfonylation of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) with cationic accelerators, the methanesulfonylation of this enzyme by high concentrations of methanesulfonylfluoride, in the absence and presence of accelerators decamethonium and tetraethylammonium, was studied. 2. The results showed that the accelerator accelerates the reaction by electrostatically improving the binding between acetylcholinesterase and methanesulfonylfluoride without effecting the rate of the decomposition of the enzyme-inhibitor complex into the methanesulfonylated enzyme and product.


Assuntos
Acetilcolinesterase , Mesilatos , Acetilcolinesterase/metabolismo , Cinética , Mesilatos/farmacologia , Ligação Proteica , Termodinâmica
11.
Biochim Biophys Acta ; 643(2): 398-406, 1981 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-7225388

RESUMO

Muscarinic and beta-adrenergic ligands associate with polymorphonuclear leukocytes to show high-affinity, saturable accumulation. This association can be distinguished from specific receptor binding by its temperature dependence, sensitivity to pH, requirement of an energy source, inhibition by ionophores, and inhibition by a variety of permeable basic amines. Our results suggest that these amines accumulate in acidic lysosomes which are plentiful in these cells. This permeable amine effect can be inhibited without affecting specific receptor binding.


Assuntos
Alprenolol/análogos & derivados , Di-Hidroalprenolol/farmacologia , Neutrófilos/metabolismo , Quinuclidinas/metabolismo , Quinuclidinil Benzilato/metabolismo , Animais , Ligação Competitiva , Transporte Biológico/efeitos dos fármacos , Encéfalo/metabolismo , Carbonil Cianeto m-Clorofenil Hidrazona/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Cinética , Masculino , Miocárdio/metabolismo , Ratos , Valinomicina/farmacologia
12.
Biochim Biophys Acta ; 403(2): 370-87, 1975 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-241402

RESUMO

Acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) is readily in hibited by 10(-5) M diphenylphosphorochloridate even though the inhibitor hydrolyzes in a few seconds. The fluoridate is a much weaker inhibitor. The inhibited enzyme, diphenyl phosphoryl enzyme spontaneously recovers only about 50% of its activity with a half time of about 17 min at pH 7.0 and 6 min at pH 8.0. The fact that only 50% of the original activity returns is due to aging. The rates of reactivation and aging can be very greatly increased by a few percent of an organic solvent. Depending on the solvent even 1% may increase the rates by a factor of 5 or 6. The highest increase in rate was 70-fold. Quaternary NH+4 also increases the rates. Organic solvents and NH+4 also accelerate the reactivation of the much more stable diethyl phosphoryl enzyme derivative.


Assuntos
Acetilcolinesterase/metabolismo , Animais , Sítios de Ligação , Dimetil Sulfóxido/farmacologia , Estabilidade de Medicamentos , Enguias , Concentração de Íons de Hidrogênio , Cinética , Matemática , Compostos Organofosforados/farmacologia , Ligação Proteica , Solventes , Fatores de Tempo
13.
Biochim Biophys Acta ; 1473(1): 216-36, 1999 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-10580141

RESUMO

Fucosylated oligosaccharides occur throughout nature and many of them play a variety of roles in biology, especially in a number of recognition processes. As reviewed here, much of the recent emphasis in the study of the oligosaccharides in mammals has been on their potential medical importance, particularly in inflammation and cancer. Indeed, changes in fucosylation patterns due to different levels of expression of various fucosyltransferases can be used for diagnoses of some diseases and monitoring the success of therapies. In contrast, there are generally at present only limited data on fucosylation in non-mammalian organisms. Here, the state of current knowledge on the fucosylation abilities of plants, insects, snails, lower eukaryotes and prokaryotes will be summarised.


Assuntos
Fucose/química , Fucosiltransferases/metabolismo , Polissacarídeos/química , Animais , Apoptose , Sequência de Carboidratos , Adesão Celular , Fertilização , Fucose/metabolismo , Fucosiltransferases/biossíntese , Fucosiltransferases/genética , Glicosilação , Crescimento , Humanos , Insetos , Dados de Sequência Molecular , Nematoides , Neoplasias/metabolismo , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Plantas , Polissacarídeos/metabolismo , Caramujos , Transfecção
14.
Biochim Biophys Acta ; 1428(1): 88-98, 1999 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-10366763

RESUMO

The preparation of the conserved core structure of asparagine-linked oligosaccharides found in eukaryotic glycoproteins is an important step towards the synthesis of homogeneous neoglycoproteins. So far, however, the convenient generation of the Manbeta4GlcNAcbeta4GlcNAc (Gn2M) core trisaccharide has proved to be a major obstacle because of the inherent difficulties associated with the synthesis of beta-mannosides. Here we report the overproduction in Escherichia coli of full-length and transmembrane-deleted yeast beta-1, 4-mannosyltransferases as novel N-terminal fusions bearing a decahistidinyl sequence and the minimal human Myc epitope. The recombinant enzymes were highly active and were amenable to immobilisation by nickel(II) chelation and to immunodetection with an anti-Myc monoclonal antibody. The immobilised, transmembrane-deleted enzyme exhibited an apparent Km of 14 microM for the synthetic acceptor substrate analogue, phytanyl-pyrophosphoryl-alpha-N,N'-diacetylchitobioside (PPGn2), under saturating donor conditions. This figure is comparable to those previously reported for native and recombinant yeast beta-1, 4-mannosyltransferases with, respectively, the natural dolichyl-linked acceptor and PPGn2. The validity of the reaction product was confirmed by chromatographic and spectroscopic analysis.


Assuntos
Enzimas Imobilizadas/biossíntese , Manosiltransferases/biossíntese , Oligossacarídeos/biossíntese , Sequência de Carboidratos , Cromatografia de Afinidade , Escherichia coli/genética , Humanos , Manosiltransferases/química , Manosiltransferases/genética , Dados de Sequência Molecular , Plasmídeos , Proteínas Recombinantes de Fusão/biossíntese
15.
Biochim Biophys Acta ; 1527(1-2): 88-96, 2001 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-11420147

RESUMO

The core alpha1,3-fucosyltransferases are involved in the synthesis of glycans specific to plants and invertebrates which are known to be immunogenic and allergenic. We report the identification, isolation and characterisation of the cDNAs of three genes (FucTA, FucTB and FucTC) encoding proteins similar to alpha1,3-fucosyltransferases in Arabidopsis thaliana. Reverse transcription-polymerase chain reaction was used to amplify the full length coding sequence of FucTA. The FucTA gene, which consists of seven exons, encodes a presumptive protein of 501 amino acids showing an overall sequence identity of 66% to the protein encoded by the recently isolated mung bean Fuc-T C3 cDNA. FucTA was expressed in Pichia pastoris under the control of the AOX1 gene promoter. The soluble enzyme was found to catalyse the same reaction as mung bean core alpha1,3-fucosyltransferase as judged by analyses of the products by MALDI-TOF and high-performance liquid chromatography. The FucTB cDNA was isolated from a lambda-ZAP library, but the clone used an alternative splicing site between the second and third exon resulting in a premature stop codon. The FucTC gene encodes a protein with less than 40% identity to FucTA across 115 amino acids of a total of 401 amino acids and is a member of a new sub-family of plant alpha1,3/4-fucosyltransferase homologues.


Assuntos
Arabidopsis/enzimologia , Fucosiltransferases/genética , Sequência de Aminoácidos , Sequência de Bases , Sequência de Carboidratos , Clonagem Molecular , DNA Complementar/análise , DNA Complementar/genética , Fucosiltransferases/biossíntese , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos
16.
Arch Intern Med ; 161(2): 256-63, 2001 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-11176741

RESUMO

BACKGROUND: Radiological studies are an important component of ambulatory medical costs, and guidelines often focus on their appropriate use. However, little is known about the correlates of the use of those services, particularly the influence of patients' preferences on physicians' utilization decisions. OBJECTIVES: To study patients presenting for outpatient treatment of respiratory problems and low back pain, and to examine the magnitude of the effect of the patients' perceived need for radiological studies (radiology preference score) on use of those services. DESIGN: Cross-sectional survey. SETTING: Office practices of generalist physicians in predominantly rural areas of 8 states. PARTICIPANTS: A total of 52 generalist physicians agreed to enroll consecutive Medicare-eligible patients making office visits for respiratory problems or low back pain. Of 1785 eligible patients invited to participate, 132 (7%) refused and 1137 (69%) of 1653 returned questionnaires. MEASUREMENTS: Radiology utilization rates (plain film, computed tomographic scan, or magnetic resonance image scan) were determined by patient self-report. To assess perceived need for radiological studies, we asked patients how necessary they believed an x-ray film was in the evaluation of 4 common complaints (respiratory problems, low back pain, knee pain, and knee swelling). A summary radiology preference score was created from 3 of the 4 items, excluding the item referring to the patients' index complaint. RESULTS: Six hundred fifteen respiratory and 522 low back pain patients were enrolled; mean ages were 69 and 64 years, respectively. Radiology utilization rates were 37% for respiratory and 26% for low back pain patients. In multiple logistic regression models, for respiratory patients radiology utilization was related significantly to the radiology preference score (odds ratio [OR] for fourth quartile compared with first quartile, 1.94; 95% confidence interval [CI], 1.11-3.37; P = .02), to having a physician who owned radiology equipment (OR, 1.81; 95% CI, 1.23-2.66; P = .002), and current smoking (OR, 1.58; 95% CI, 1.04-2.41; P = .03). For low back pain patients, radiology utilization was significantly related to the radiology preference score (OR for fourth compared with first quartile, 2.55; 95% CI, 1.29-5.06; P = .007), bothersomeness of the pain (OR for fourth compared with first quartile, 3.74; 95% CI, 1.74-8.04; P<.001), and a diagnosis of osteoporosis (OR, 1.67; 95% CI, 1.01-2.75; P = .04). CONCLUSIONS: Patients' perceived need for radiological studies was significantly associated with use of those services for outpatients with respiratory problems and low back pain. These findings suggest that patients communicate their wishes to physicians, either directly or indirectly, regarding services they think are necessary. Differences in physicians' adherence to guidelines regarding radiology utilization may in part reflect variations in patients' perceived need for those services. Efforts to educate patients about when radiological studies are medically indicated may be an important complement to practice guidelines or other utilization-related financial incentives.


Assuntos
Assistência Ambulatorial , Medicina de Família e Comunidade , Imageamento por Ressonância Magnética/estatística & dados numéricos , Satisfação do Paciente , Radiografia/estatística & dados numéricos , Idoso , Atitude Frente a Saúde , Feminino , Humanos , Dor Lombar/diagnóstico , Dor Lombar/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Doenças Respiratórias/diagnóstico , Doenças Respiratórias/diagnóstico por imagem , Fumar , Fatores Socioeconômicos
17.
Virulence ; 6(3): 282-92, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25831954

RESUMO

The periodontal pathogen Tannerella forsythia expresses several glycosidases which are linked to specific growth requirements and are involved in the invasion of host tissues. α-l-Fucosyl residues are exposed on various host glycoconjugates and, thus, the α-l-fucosidases predicted in the T. forsythia ATCC 43037 genome could potentially serve roles in host-pathogen interactions. We describe the molecular cloning and characterization of the putative fucosidase TfFuc1 (encoded by the bfo_2737 = Tffuc1 gene), previously reported to be present in an outer membrane preparation. In terms of sequence, this 51-kDa protein is a member of the glycosyl hydrolase family GH29. Using an artificial substrate, p-nitrophenyl-α-fucose (KM 670 µM), the enzyme was determined to have a pH optimum of 9.0 and to be competitively inhibited by fucose and deoxyfuconojirimycin. TfFuc1 was shown here to be a unique α(1,2)-fucosidase that also possesses α(1,6) specificity on small unbranched substrates. It is active on mucin after sialidase-catalyzed removal of terminal sialic acid residues and also removes fucose from blood group H. Following knock-out of the Tffuc1 gene and analyzing biofilm formation and cell invasion/adhesion of the mutant in comparison to the wild-type, it is most likely that the enzyme does not act extracellularly. Biochemically interesting as the first fucosidase in T. forsythia to be characterized, the biological role of TfFuc1 may well be in the metabolism of short oligosaccharides in the periplasm, thereby indirectly contributing to the virulence of this organism. TfFuc1 is the first glycosyl hydrolase in the GH29 family reported to be a specific α(1,2)-fucosidase.


Assuntos
Bacteroidetes/enzimologia , Periodontite/microbiologia , alfa-L-Fucosidase/genética , alfa-L-Fucosidase/metabolismo , Animais , Bacteroidetes/genética , Bacteroidetes/patogenicidade , Clonagem Molecular , Fucose/metabolismo , Interações Hospedeiro-Patógeno , Cinética , Mucinas/metabolismo , Oligossacarídeos/metabolismo , Especificidade por Substrato , alfa-L-Fucosidase/química
18.
AIDS ; 12(13): 1645-51, 1998 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-9764784

RESUMO

OBJECTIVES: To determine the nutritional changes that occur in HIV-infected patients receiving protease inhibitor (PI) therapy and to determine the effects of PI treatment on physical functioning and health perceptions in patients with HIV infection. DESIGN: Longitudinal data analysis of 38 patients from a large Nutrition and HIV cohort. METHODS: Patients were included if they had started PI therapy after enrollment in the cohort, if they had taken the drug for at least 4 months without interruption and if data on weight, body composition and viral loads were available. RESULTS: Mean person-months of follow-up was 8.1 months before and 12.2 months after PI treatment. Weight (1.54 kg, P < 0.0001), body mass index (0.50 kg/m2, P < 0.0001), physical functioning (8.52 points, P = 0.0006) and current health perception (6.7 points, P = 0.01) increased significantly, and the daily caloric intake increase was close to significance (915.5 kJ/day, P = 0.06), after treatment with PI. Lean body mass did not change. Patients who responded to PI therapy with decreased viral load (n = 28) had significantly greater weight gain per month than non-responders. CONCLUSIONS: PI therapy of HIV infection is associated with weight gain and improvement in quality of life indices. The weight gain is mainly in fat mass, with no change in lean body mass (skeletal muscle). Optimal therapy of HIV-infected patients with weight loss may require highly active antiretroviral therapy combined with an anabolic stimulus such as exercise, anabolic steroids or human growth hormone.


Assuntos
Composição Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/uso terapêutico , Estado Nutricional/efeitos dos fármacos , Adulto , Estudos de Coortes , Quimioterapia Combinada , Feminino , Humanos , Indinavir/uso terapêutico , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Ritonavir/uso terapêutico , Saquinavir/uso terapêutico , Carga Viral
19.
FEBS Lett ; 472(1): 105-8, 2000 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-10781814

RESUMO

The transfer of xylose from UDP-xylose to the core beta-linked mannose of N-linked oligosaccharides by beta1,2-xylosyltransferase (XylT) is a widespread feature of plant glycoproteins which renders them immunogenic and allergenic in man. Here, we report the isolation of the Arabidopsis thaliana XylT gene, which contains two introns and encodes a 60.2 kDa protein with a predicted type II transmembrane protein topology typical for Golgi glycosyltransferases. Upon expression of A. thaliana XylT cDNA in the baculovirus/insect cell system, a recombinant protein was produced that exhibited XylT activity in vitro. Furthermore, the recombinant enzyme displayed XylT activity in vivo in the insect cells, as judged by the acquired cross-reaction of cellular glycoproteins with antibodies against the beta1,2-xylose epitope. The cloned XylT cDNA as well as the recombinant enzyme are essential tools to study the role of beta1,2-xylose in the immunogenicity and allergenicity of plant glycoproteins at the molecular level.


Assuntos
Arabidopsis/genética , Pentosiltransferases/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Clonagem Molecular , DNA Complementar , Dados de Sequência Molecular , Pentosiltransferases/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Spodoptera/citologia
20.
Biochimie ; 83(8): 703-12, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11530201

RESUMO

Recently the genomic sequences of three multicellular eukaryotes, Caenorhabditis elegans, Drosophila melanogaster and Arabidopsis thaliana, have been elucidated. A number of cDNAs encoding glycosyltransferases demonstrated to have a role in N-linked glycosylation have already been cloned from these organisms, e.g., GlcNAc transferases and alpha 1,3-fucosyltransferases. However, many more homologues of glycosyltransferases and other glycan modifying enzymes have been predicted by analysis of the genome sequences, but the predictions of full length open reading frames appear to be particularly poor in Caenorhabditis. The use of these organisms as models in glycobiology may be hampered since they all have N-linked glycosylation repertoires unlike those of mammals. Arabidopsis and Drosophila have glycosylation similar to that of other plants or insects, while our new data from MALDI-TOF analysis of PNGase A-released neutral N-glycans of Caenorhabditis indicate that there exists a range of pauci- and oligomannosidic structures, with up to four fucose residues and up to two O-methyl groups. With all these three 'genetic model organisms', however, much more work is required for a full understanding of their glycobiology.


Assuntos
Glicosiltransferases/genética , Polissacarídeos/metabolismo , Animais , Arabidopsis/enzimologia , Arabidopsis/genética , Caenorhabditis elegans/enzimologia , Caenorhabditis elegans/genética , Drosophila melanogaster/enzimologia , Drosophila melanogaster/genética , Humanos , Modelos Genéticos
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