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1.
BMC Neurol ; 21(1): 257, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215196

RESUMO

BACKGROUND: Erenumab, a monoclonal antibody against the calcitonin gene-related peptide (CGRP) receptor, is registered for migraine prevention. Compared to other conventional migraine prevention medicines (i.e. topiramate, betablockers and amitriptyline) erenumab has better tolerability. Impaired hemostasis has not been reported previously. Here, we report the first case of an increased tendency to bruise in a migraine patient treated with erenumab. CASE PRESENTATION: A 41-year old female migraine patient was treated with erenumab for 12 months, which led to a significant reduction of headache and migraine days. Three months after treatment start, she experienced increased tendency to bruise leading to extreme ecchymosis after 4 months treatment. Platelet counts and aggregation, thromboelastography, activated partial thromboplastin time (APTT) and international normalized ratio (INR) were all normal. Thorough interview revealed intake of fish oil supplements for many years prior to treatment. The increased tendency to bruise subsided after discontinuation of fish oil supplements. CONCLUSION: The combination of fish oil supplements and erenumab may cause increased tendency to bruise. Erenumab has no effect on the platelets per se but may cause impaired wound healing by suppression of CGRP. Thus, small and unnoticeable bruises may be aggravated instead in patients with tendency to bruise caused by for instance fish oil supplements.


Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina/efeitos adversos , Equimose/induzido quimicamente , Óleos de Peixe , Transtornos de Enxaqueca/tratamento farmacológico , Adulto , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina/uso terapêutico , Feminino , Óleos de Peixe/efeitos adversos , Óleos de Peixe/uso terapêutico , Humanos
2.
Phys Rev Lett ; 120(23): 230406, 2018 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-29932709

RESUMO

Conventional wisdom is that quantum effects will tend to disappear as the number of quanta in a system increases, and the evolution of a system will become closer to that described by mean-field classical equations. In this Letter we combine newly developed theoretical and experimental techniques to propose and analyze an experiment using a Bose-Hubbard trimer where the opposite is the case. We find that differences in the preparation of a centrally evacuated trimer can lead to readily observable differences in the subsequent dynamics which increase with system size. Importantly, these differences can be detected by the simple measurements of atomic number.

3.
Phys Rev Lett ; 119(16): 160501, 2017 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-29099216

RESUMO

We propose and analyze a nonlinear optical apparatus in which the direction of asymmetric steering is controllable within the apparatus, rather than by adding noise to measurements. Using a nondegenerate parametric oscillator with an injected signal field, we show how the directionality and extent of the steering can be readily controlled for output modes that can be up to one octave apart. The two down-converted modes, which exhibit the greater violations of the steering inequalities, can also be controlled to exhibit asymmetric steering in some regimes.

4.
Obes Sci Pract ; 2(4): 355-365, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-28090340

RESUMO

OBJECTIVE: A weight loss maintenance trial involving weight loss prior to randomization is challenging to implement due to the potential for dropout and insufficient weight loss. We examined rates and correlates of non-initiation, dropout, and insufficient weight loss during a weight loss maintenance trial. METHODS: The MAINTAIN trial involved a 16-week weight loss program followed by randomization among participants losing at least 4 kg. Psychosocial measures were administered during a screening visit. Weight was obtained at the first group session and 16 weeks later to determine eligibility for randomization. RESULTS: Of 573 patients who screened as eligible, 69 failed to initiate the weight loss program. In adjusted analyses, failure to initiate was associated with lower age, lack of a support person, and less encouragement for making dietary changes. Among participants who initiated, 200 dropped out, 82 lost insufficient weight, and 222 lost sufficient weight for randomization. Compared to losing sufficient weight, dropping out was associated with younger age and tobacco use, whereas losing insufficient weight was associated with non-White race and controlled motivation for physical activity. CONCLUSIONS: Studies should be conducted to evaluate strategies to maximize recruitment and retention of subgroups that are less likely to initiate and be retained in weight loss maintenance trials.

5.
J Hum Nutr Diet ; 28 Suppl 2: 16-23, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24251378

RESUMO

BACKGROUND: Identifying pretreatment dietary habits that are associated with weight-loss intervention outcomes could help guide individuals' selection of weight-loss approach among competing options. A pretreatment factor that may influence weight-loss outcomes is macronutrient intake. METHODS: Overweight and obese Durham Veterans Affairs outpatients were randomised to a weight-loss intervention with a low-carbohydrate diet (n = 71) or orlistat medication therapy plus a low-fat diet (n = 73). Percentage fat, carbohydrate and protein intake prior to treatment were measured using 4-day food records. Linear mixed-effects models were used to determine whether pretreatment percentage macronutrient intake influenced weight trajectories and weight loss in each weight-loss condition. RESULTS: Participant's mean age was 53 years, baseline body mass index was 39.3 kg m(-2) and 72% were male. A higher pretreatment percentage carbohydrate intake was associated with less rapid initial weight loss (P = 0.02) and less rapid weight regain (P = 0.03) in the low-carbohydrate diet condition but was not associated with weight trajectories in the orlistat plus low-fat diet condition. In both conditions, a higher pretreatment percentage fat intake was associated with more rapid weight regain (P < 0.01). Pretreatment percentage protein intake was not associated with weight trajectories. None of the pretreatment macronutrients were associated with weight loss on study completion in either condition. CONCLUSIONS: Selection of a weight-loss approach on the basis of pretreatment macronutrient intake is unlikely to improve weight outcomes at the end of a 1-year treatment. However, pretreatment macronutrient intake may have implications for tailoring of interventions to slow weight regain after weight loss.


Assuntos
Dieta Redutora , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Comportamento Alimentar , Obesidade/dietoterapia , Redução de Peso , Adulto , Fármacos Antiobesidade/uso terapêutico , Dieta com Restrição de Carboidratos , Dieta com Restrição de Gorduras , Ingestão de Energia , Feminino , Humanos , Lactonas/uso terapêutico , Masculino , Pessoa de Meia-Idade , Obesidade/tratamento farmacológico , Orlistate , Aumento de Peso
6.
Diabetes Obes Metab ; 16(1): 90-3, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23911112

RESUMO

We analysed participants with type 2 diabetes (n = 46) within a larger weight loss trial (n = 146) who were randomized to 48 weeks of a low-carbohydrate diet (LCD; n = 22) or a low-fat diet + orlistat (LFD + O; n = 24). At baseline, mean body mass index (BMI) was 39.5 kg/m(2) (s.d. 6.5) and haemoglobin A1c (HbA1c) 7.6% (s.d. 1.3). Although the interventions reduced BMI similarly (LCD -2.4 kg/m(2) ; LFD + O -2.7 kg/m(2) , p = 0.7), LCD led to a relative improvement in HbA1c: -0.7% in LCD versus +0.2% in LFD + O [difference -0.8%, 95% confidence interval (CI) = -1.6, -0.02; p = 0.045]. LCD also led to a greater reduction in antiglycaemic medications using a novel medication effect score (MES) based on medication potency and total daily dose; 70.6% of LCD versus 30.4% LFD + O decreased their MES by ≥50% (p = 0.01). Lowering dietary carbohydrate intake demonstrated benefits on glycaemic control beyond its weight loss effects, while at the same time lowering antiglycaemic medication requirements.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/dietoterapia , Dieta com Restrição de Carboidratos , Dieta com Restrição de Gorduras , Dieta Redutora , Hemoglobinas Glicadas/metabolismo , Hipoglicemiantes/farmacologia , Redução de Peso , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , Resultado do Tratamento
7.
Eur J Clin Nutr ; 61(12): 1416-22, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17299473

RESUMO

OBJECTIVE: To examine the effects of low-carbohydrate, ketogenic (LCKD) and low-fat (LFD) diets on acid-base status. DESIGN: Prospective analysis of volunteers from two clinical trials. PARTICIPANTS: Subset of 39 volunteers from a randomized trial comparing the effects of an LCKD with an LFD, and a single-arm trial of an LCKD. SETTING: Outpatient research clinic. INTERVENTION: LCKD (initially <20 g of carbohydrate daily) or LFD (<30% of energy from fat, 500-1000 kcal energy reduction) instruction. MEASUREMENTS: Arterial blood gas analysis, serum chemistries (electrolytes, urea nitrogen/creatinine, glucose, ketone bodies, lactate), anion gap, and urine ketone bodies measured at weeks 0, 2, 8, and 24. RESULTS: Participants had a mean (+/-standard deviation) age of 43.5+/-9.3 years; 28 (72%) were female, 29 (74%) were Caucasian. Using linear mixed-model analysis to examine blood test changes from baseline to 24 weeks, the LFD group experienced a decrease in arterial blood pH from a mean of 7.43 at week 0 to 7.40 at week 24 (P=0.03), and the LCKD group experienced a decrease from 7.42 at week 0 to 7.40 at week 24 (P=0.01). The lowest pH measurements observed were 7.34 in the LFD group and 7.37 in the LCKD group. Although serum bicarbonate appeared to decrease from baseline at weeks 2 and 8 in the LCKD group, the change at 24 weeks was not statistically significant in either diet group, and only four of 131 (two of 92 from the LCKD group) measurements were less than 22 mmol/l. The proportion of participants with elevated urine and serum ketone body levels rose in the LCKD group only, was highest at week 2, and decreased over the subsequent time points. CONCLUSION: In individuals following an LCKD or an LFD, blood pH decreased mildly and the LCKD group experienced a small, transient decrease in serum bicarbonate in conjunction with mild ketosis. This suggests that an LCKD induced a mild compensated metabolic acidosis, but no individual showed evidence of significant metabolic derangement.


Assuntos
Equilíbrio Ácido-Base/fisiologia , Dieta com Restrição de Carboidratos , Dieta com Restrição de Gorduras , Corpos Cetônicos/análise , Obesidade/dietoterapia , Redução de Peso/fisiologia , Acidose/epidemiologia , Acidose/etiologia , Adulto , Análise Química do Sangue , Gasometria , Feminino , Humanos , Concentração de Íons de Hidrogênio , Modelos Lineares , Masculino , Obesidade/metabolismo , Estudos Prospectivos
8.
Phys Rev Lett ; 96(13): 133601, 2006 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-16711985

RESUMO

We introduce a scheme for creating continuous variable entanglement between an atomic beam and an optical field, by using squeezed light to outcouple atoms from a Bose-Einstein condensate via a Raman transition. We model the full multimode dynamics of the atom laser beam and the squeezed optical field and show that, with appropriate two-photon detuning and two-photon Rabi frequency, the transmitted light is entangled in amplitude and phase with the outcoupled atom laser beam. The degree of entanglement is controllable via changes in the two-photon Rabi frequency of the outcoupling process.

9.
Phys Rev Lett ; 95(15): 150405, 2005 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-16241704

RESUMO

Recent experimental measurements of atomic intensity correlations through atom shot noise suggest that atomic quadrature phase correlations may soon be measured with a similar precision. We propose a test of local realism with mesoscopic numbers of massive particles based on such measurements. Using dissociation of a Bose-Einstein condensate of diatomic molecules into bosonic atoms, we demonstrate that strongly entangled atomic beams may be produced which possess Einstein-Podolsky-Rosen (EPR) correlations in field quadratures in direct analogy to the position and momentum correlations originally considered by EPR.

10.
Phys Rev Lett ; 86(15): 3220-3, 2001 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-11327936

RESUMO

We show that in certain parameter regimes there is a macroscopic dynamical breakdown of the Gross-Pitaevskii equation. Stochastic field equations for coupled atomic and molecular condensates are derived using the functional positive- P representation. These equations describe the full quantum state of the coupled condensates and include the commonly used Gross-Pitaevskii equation as the noiseless limit. The full quantum theory includes the spontaneous processes which will become significant when the atomic population is low. The experimental signature of the quantum effects will be the time scale of the revival of the atomic population after a near total conversion to the molecular condensate.

11.
Ann Neurol ; 50(6): 730-40, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11761470

RESUMO

Mutations of copper,zinc-superoxide dismutase (cu,zn SOD) are found in patients with a familial form of amyotrophic lateral sclerosis. When expressed in transgenic mice, mutant human cu,zn SOD causes progressive loss of motor neurons with consequent paralysis and death. Expression profiling of gene expression in SOD1-G93A transgenic mouse spinal cords indicates extensive glial activation coincident with the onset of paralysis at 3 months of age. This is followed by activation of genes involved in metal ion regulation (metallothionein-I, metallothionein-III, ferritin-H, and ferritin-L) at 4 months of age just prior to end-stage disease, perhaps as an adaptive response to the mitochondrial destruction caused by the mutant protein. Induction of ferritin-H and -L gene expression may also limit iron catalyzed hydroxyl radical formation and consequent oxidative damage to lipids, proteins, and nucleic acids. Thus, glial activation and adaptive responses to metal ion dysregulation are features of disease in this transgenic model of familial amyotrophic lateral sclerosis.


Assuntos
Perfilação da Expressão Gênica , Medula Espinal/fisiologia , Superóxido Dismutase/genética , Idade de Início , Esclerose Lateral Amiotrófica/genética , Animais , Antioxidantes/metabolismo , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Catepsinas/genética , Catepsinas/metabolismo , Transporte de Elétrons/genética , Transporte de Elétrons/fisiologia , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Camundongos , Camundongos Transgênicos , ATPases Mitocondriais Próton-Translocadoras/genética , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Neuroglia/química , Neuroglia/fisiologia , Medula Espinal/citologia , Estatística como Assunto , Superóxido Dismutase/metabolismo , Timosina/genética , Timosina/metabolismo , Transcrição Gênica/fisiologia , Vimentina/genética , Vimentina/metabolismo , beta-N-Acetil-Hexosaminidases/genética , beta-N-Acetil-Hexosaminidases/metabolismo
12.
Qual Life Res ; 9(7): 829-39, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11297025

RESUMO

The relationship between perceived social support and domain-specific health-related quality of life (HRQOL) was examined in a sample of cardiac catheterization patients after considering age, gender, race, education, and coronary artery disease (CAD) severity. Data was collected on 4,278 cardiac catheterization patients (63% males) and included 1,215 patients with non-significant CAD and 3,063 patients who had significant CAD ( > or = 75% stenosis of at least one major coronary artery). Among the patients with significant CAD, 2,721 were classified as low disease severity and 342 were considered high disease severity. Regression models indicated that a lack of social support was associated with significantly lower levels of HRQOL across all eight SF-36 HRQOL domains after considering disease severity and other demographic factors. The models also indicated that social support and other relevant variables interacted across various HRQOL domains. Physical function and physical role function were lower with age, whereas mental health, emotional role function, and vitality were higher with age. Females reported lower HRQOL than males across all domains. Minority patients reported lower levels of HRQOL than white patients across four domains. Increased disease severity was related to lower levels among four of the eight HRQOL domains. The observed interactions of social support with minority status, disease severity, and education suggest that a subset of individuals may suffer lower levels of HRQOL. These individuals may subsequently require the greatest degree of care and potentially benefit most from intervention.


Assuntos
Doença das Coronárias/psicologia , Qualidade de Vida , Apoio Social , Adulto , Idoso , Idoso de 80 Anos ou mais , Cateterismo Cardíaco , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Índice de Gravidade de Doença
13.
J Cell Physiol ; 176(3): 525-36, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9699505

RESUMO

We previously identified KT5720 and U-98017 as agents that had paclitaxel (taxol)-like activity in a Chinese hamster ovary (CHO) paclitaxel-dependent cell screen for paclitaxel mimetics. In vitro polymerization of purified brain tubulin is not affected substantially by these compounds, suggesting that, unlike paclitaxel, these agents do not directly affect tubulin. However, these compounds cause profound rearrangements of the cytoskeleton in intact cells, including an apparent alteration of microtubule length, overlapping of cells, and an increase in cell size. We show that KT5720 and U-98017 effectively inhibit mitogen-activated protein kinase (MAPK) activity in vitro. Staurosporine, a poor inhibitor of MAPK but a potent inhibitor of cAMP-dependent protein kinase A (PKA) activity, phospholipid/Ca++-dependent kinase (PKC), and cdc2, does not cause similar changes. In addition, paclitaxel-dependent cells grown in U-98017 have substantially decreased levels of stimulated MAPK. In correlation with these results, we have confirmed the presence of MAPK in isolated tubulin and microtubules in cells. We have examined the hypothesis that these compounds are working through inhibition of MAPK to alter microtubules by inhibiting the phosphorylation of microtubule-associated proteins. A MAPKK dominant negative mutation transfected in CHO cells inhibits activation of MAPK. Transfectants carrying this dominant mutant have impaired activation of MAPK and an altered cell morphology, similar in some respects to that seen with KT5720 and U-98017. These results support a role for MAPK family members in the control of microtubule dynamics and suggest that in intact cells U-98017 and KT5720 achieve their effects of altering cytoskeleton and supporting partial growth of paclitaxel-dependent cells through inhibition of kinases such as MAPK.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Carbazóis , Citoesqueleto/metabolismo , Inibidores Enzimáticos/farmacologia , Indóis/farmacologia , Pirróis/farmacologia , Animais , Anticorpos , Antineoplásicos Fitogênicos/farmacologia , Células CHO/citologia , Células CHO/efeitos dos fármacos , Células CHO/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/análise , Proteínas Quinases Dependentes de Cálcio-Calmodulina/imunologia , Tamanho Celular/efeitos dos fármacos , Cricetinae , Técnica Indireta de Fluorescência para Anticorpo , Quinases de Proteína Quinase Ativadas por Mitógeno , Paclitaxel/farmacologia , Proteínas Quinases/metabolismo , Estaurosporina/farmacologia , Tubulina (Proteína)/análise , Tubulina (Proteína)/imunologia
14.
Multivariate Behav Res ; 33(4): 545-71, 1998 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26753828

RESUMO

Analyses of multivariate data are frequently hampered by missing values. Until recently, the only missing-data methods available to most data analysts have been relatively ad1 hoc practices such as listwise deletion. Recent dramatic advances in theoretical and computational statistics, however, have produced anew generation of flexible procedures with a sound statistical basis. These procedures involve multiple imputation (Rubin, 1987), a simulation technique that replaces each missing datum with a set of m > 1 plausible values. The rn versions of the complete data are analyzed by standard complete-data methods, and the results are combined using simple rules to yield estimates, standard errors, and p-values that formally incorporate missing-data uncertainty. New computational algorithms and software described in a recent book (Schafer, 1997a) allow us to create proper multiple imputations in complex multivariate settings. This article reviews the key ideas of multiple imputation, discusses the software programs currently available, and demonstrates their use on data from the Adolescent Alcohol Prevention Trial (Hansen & Graham, 199 I).

15.
J Bacteriol ; 175(21): 7092-6, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8226651

RESUMO

Plasmid libraries of prlA mutants containing single-base-pair changes throughout the gene were generated by in vitro random mutagenesis. The prlA mutations capable of suppressing the secretion defect of LamB caused by mutations in the LamB signal peptide were selected and analyzed. Together with additional mutations generated by site-directed mutagenesis, a number of novel prlA mutations and/or suppressors were identified. These mutations provide the starting points for studying the relationship of structure and function of PrlA in its interaction with LamB and/or other component(s) in the Escherichia coli protein secretion-translocation complex.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Escherichia coli , Escherichia coli/genética , Genes Bacterianos , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias/química , Escherichia coli/isolamento & purificação , Biblioteca Gênica , Mutagênese Sítio-Dirigida , Plasmídeos , Porinas , Sinais Direcionadores de Proteínas/biossíntese , Sinais Direcionadores de Proteínas/genética , Estrutura Secundária de Proteína , Receptores Virais/biossíntese , Mapeamento por Restrição , Canais de Translocação SEC , Supressão Genética
16.
Cytotechnology ; 10(2): 157-67, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1369211

RESUMO

We have studied the expression of an analog of human tissue plasminogen activator, FK2P, in Drosophila Schneider 2 cells. A number of promoters were tested, including the Drosophila metallothionein promoter (MTd), baculovirus immediate early promoter (IE), Drosophila copia promoter, mouse metallothionein promoter, cytomegalovirus immediate early promoter with or without intron, SV40 immediate early promoter, and human elongation factor 1 alpha promoter. Two of these promoters drove significant expression of FK2P. The MTd promoter is tightly regulated and upon induction with copper or cadmium expression of FK2P increases as much as 180-fold, accumulating in the culture medium to about 7 micrograms FK2P/10(6) cells/day as determined by ELISA. The IE promoter can direct the constitutive expression to yield about 0.4 microgram FK2P/10(6) cells/day. The production of FK2P in these cell lines remains at about the same level after repeated passages, even in the absence of selective pressure. The FK2P accumulated in the culture medium is fully active in an assay using a chromogenic substrate for serine proteases. Western immunoblot analysis shows that the product remains predominantly as single-chain molecules in serum-free medium, while in serum-containing medium two-chain material occurs as expected due to the presence of plasmin in serum. Judged from the size in Western immunoblots, the FK2P produced is glycosylated.


Assuntos
Cinamatos , Drosophila melanogaster/citologia , Proteínas Recombinantes de Fusão/biossíntese , Ativador de Plasminogênio Tecidual/biossíntese , Sequência de Aminoácidos , Animais , Sequência de Bases , Meios de Cultura Livres de Soro , Resistência a Medicamentos , Regulação da Expressão Gênica/efeitos dos fármacos , Vetores Genéticos , Humanos , Higromicina B/análogos & derivados , Higromicina B/farmacologia , Metalotioneína/genética , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/farmacologia , Ativador de Plasminogênio Tecidual/farmacologia
17.
AIDS Res Hum Retroviruses ; 6(4): 543-52, 1990 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2187504

RESUMO

A simple Escherichia coli system has been developed for the detection of human immunodeficiency virus (HIV) protease activity. In this system, the protease sequence is placed downstream of the HIV gag polypeptide in an operon arrangement. Upon expression of the operon, gag serves as the substrate for the protease; the level of protease activity can be determined by measurement of the cleavage product of gag in cell extracts by Western immunoblotting. This system is useful in both detection of protease mutations generated by mutagenesis and in testing substrate specificity of the protease by mutagenesis of the gag sequence. Using this system, we have observed that modification of the N-terminus of HIV protease renders the enzyme temperature sensitive; the temperature sensitivity is made more pronounced by the conserved change of valine to isoleucine at residue eleven.


Assuntos
Endopeptidases/análise , Escherichia coli/genética , Produtos do Gene pol/análise , Endopeptidases/biossíntese , Endopeptidases/genética , Produtos do Gene gag/biossíntese , Produtos do Gene pol/biossíntese , Produtos do Gene pol/genética , Vetores Genéticos , Protease de HIV , Mutação , Óperon , Temperatura
18.
Biochemistry ; 29(1): 264-9, 1990 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-2182116

RESUMO

The aspartyl protease of human immunodeficiency virus 1 (HIV-1) has been expressed in Escherichia coli at high levels, resulting in the formation of inclusion bodies which contain denatured insoluble aggregates of the protease. After solubilization of these inclusion bodies in guanidinium chloride, the protease was purified to apparent homogeneity by a single-step reverse-phase HPLC procedure. The purified, but inactive, protein was denatured in 8 M urea and refolded to produce the active protease. Enzyme activity was demonstrated against the substrate H-Val-Ser-Gln-Asn-Tyr-Pro-Ile-Val-OH, modeled after the cleavage region between residues 128 and 135 in the HIV gag polyprotein. With this substrate, a Vmax of 1.3 +/- 0.2 mumol/(min.mg) and KM of 2.0 +/- 0.3 mM were determined at pH 5.5. Pepstatin (Iva-Val-Val-Sta-Ala-Sta-OH) and substrate analogues with the Tyr-Pro residues substituted by Sta, by Phe psi [CH2N]Pro, and by Leu psi [CH(OH)CH2]Val inhibited the protease with KI values of 360 nM, 3690 nM, 3520 nM, and less than 10 nM, respectively. All were competitive inhibitors, and the tightest binding compound provided an active site titrant for the quantitative determination of enzymatically active HIV-1 protease.


Assuntos
Endopeptidases/metabolismo , Produtos do Gene pol/metabolismo , Proteínas Recombinantes/isolamento & purificação , Sequência de Aminoácidos , Sítios de Ligação , Cromatografia Líquida de Alta Pressão , Endopeptidases/genética , Endopeptidases/isolamento & purificação , Inibidores Enzimáticos/farmacologia , Escherichia coli/enzimologia , Regulação Enzimológica da Expressão Gênica , Produtos do Gene pol/genética , Produtos do Gene pol/isolamento & purificação , Protease de HIV , HIV-1/enzimologia , Cinética , Dados de Sequência Molecular , Estrutura Molecular , Pepstatinas/farmacologia , Conformação Proteica , Proteínas Recombinantes/genética
19.
Nucleic Acids Res ; 17(8): 3179-97, 1989 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-2657656

RESUMO

We have studied the expression of bovine somatotropin (BSt) to gain more understanding of various factors affecting translation in E. coli. The unmodified cDNA coding for mature bovine somatotropin does not produce significant amounts of BSt in E. coli using a pBR322-derived vector. However, a translation fusion with 16 codons from trpLE in front of BSt cDNA results in greater than 20% of total cell protein as the fusion product. Analysis of transcription by measuring the rate and integrity of the mRNA confirms that a post-transcriptional event is responsible for the poor expression of the BSt cDNA. There are two potential stem-loop structures in the 5' region of the mRNA which may interfere with translation. To study their effect on translation, lacZ fusions and oligonucleotide mutagenesis were carried out. The results demonstrate that the secondary structure involving the initiation codon blocks translation initiation. Removal of this stem-loop results in a 100-fold increase in BSt expression. However, the expression level is still low, amounting to only 0.5-1% of total cell protein. High level expression can be obtained by replacement of the beginning sequence of BSt cDNA with trpLE codons. These results suggest that in addition to the secondary structure, the nucleotide sequence or amino acid context within the beginning of BSt is incompatible with one of the steps in translation initiation.


Assuntos
Regulação da Expressão Gênica , Hormônio do Crescimento/genética , Iniciação Traducional da Cadeia Peptídica , RNA Mensageiro/genética , Proteínas Recombinantes/genética , Clonagem Molecular , Replicação do DNA , Escherichia coli/genética , Ligação de Hidrogênio , Técnicas In Vitro , Conformação de Ácido Nucleico , Plasmídeos , RNA Mensageiro/ultraestrutura , Sequências Reguladoras de Ácido Nucleico
20.
Plasmid ; 20(2): 167-70, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3148948

RESUMO

For use in monitoring transcription in operon fusion, we have constructed a lacZ sequence with the initiation codon ATG and the Escherichia coli consensus Shine-Dalgarno site. There are unique restriction endonuclease sites flanking the sequence to allow easy isolation of the lacZ sequence with or without the Shine-Dalgarno site. We have placed this lacZ sequence behind the bovine growth hormone (BGH) gene and found that the lacZ product beta-galactosidase synthesized reflects the level of BGH-specific mRNA.


Assuntos
Escherichia coli/genética , Genes Bacterianos , Óperon Lac , Plasmídeos , Transcrição Gênica , Animais , Bovinos , Clonagem Molecular , Códon , Genes , Hormônio do Crescimento/genética , Sondas de Oligonucleotídeos , Mapeamento por Restrição , beta-Galactosidase/genética
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