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1.
J Interpers Violence ; 38(3-4): 4486-4506, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35924322

RESUMO

In the current study, we utilized a person-centered approach to examine the relations of parental psychological control (PPC) and relationship self-efficacy (RSE) to power dynamics in emerging adults' romantic relationships. College student emerging adults (N = 312) completed measures assessing retrospective PPC, RSE, and perceived self and partner power in current relationships. Latent profile analysis uncovered four relationship types based on reported self- and partner-power: balanced-unified, balanced-interchanging, unbalanced-high self, and unbalanced-high partner. Increases in PPC were related to increased odds of being in an unbalanced relationship. Higher levels of RSE were associated with decreased odds of being in an unbalanced relationship. Further, even individuals in the balanced profile who reported average levels of both self and partner power (balanced-interchanging) reported higher levels of PPC and lower levels of RSE compared to those in the balanced group where levels of both self and partner power were low (balanced-unified). These findings suggest using a person-centered approach to relationship power may advance our conceptualization of power distribution in romantic relationships. Further, experienced family dynamics and one's sense of self may be especially important for young adults' tendency to form healthy relationships. The current findings encourage future investigation into the mechanisms by which parental factors predict both dominance and submissiveness in romantic relationships. Understanding predictors of power dynamics may contribute to intimate partner violence prevention and intervention.


Assuntos
Violência por Parceiro Íntimo , Autoeficácia , Adulto Jovem , Humanos , Estudos Retrospectivos , Relações Interpessoais , Pais
2.
CPT Pharmacometrics Syst Pharmacol ; 6(4): 267-276, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28074615

RESUMO

The purpose of this study was to create an open access repository of validated liquid chromatography tandem mass spectrometry (LC-MS/MS) multiple reaction monitoring (MRM) methods for quantifying 284 important proteins associated with drug absorption, distribution, metabolism, and excretion (ADME). Various in silico and experimental approaches were used to select surrogate peptides and optimize instrument parameters for LC-MS/MS quantification of the selected proteins. The final methods were uploaded to an online public database (QPrOmics; www.qpromics.uw.edu/qpromics/assay/), which provides essential information for facile method development in triple quadrupole mass spectrometry (MS) instruments. To validate the utility of the methods, the differential tissue expression of 107 key ADME proteins was characterized in the tryptic digests of the pooled subcellular fractions of human liver, kidneys, intestines, and lungs. These methods and the data are critical for development of physiologically based pharmacokinetic (PBPK) models to predict xenobiotic disposition.


Assuntos
Bases de Dados de Proteínas , Mucosa Intestinal/metabolismo , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Farmacocinética , Proteômica/métodos , Cromatografia Líquida , Reposicionamento de Medicamentos , Humanos , Intestinos/efeitos dos fármacos , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Modelos Teóricos , Proteoma/efeitos dos fármacos , Espectrometria de Massas em Tandem
3.
Clin Pharmacol Ther ; 91(4): 673-84, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22398970

RESUMO

Mechanisms by which efavirenz diminishes methadone plasma concentrations are unknown. This investigation determined efavirenz influence on clinical methadone disposition and miosis, intravenous and oral alfentanil clearance (hepatic and intestinal cytochrome P450 3A4/5 (CYP3A4/5) activity), fexofenadine disposition (intestinal transporters activity), and efavirenz clearance and 8-hydroxylation (CYP2B6 activity), and human hepatocyte effects. Efavirenz induced systemic and oral alfentanil clearances two- to fivefold and induced efavirenz 8-hydroxylation. Efavirenz stereoselectively decreased methadone plasma concentrations 50-70%. Methadone systemic and oral clearances, hepatic clearance and extraction ratio, N-demethylation, and metabolite formation clearance were stereoselectively increased two- to threefold. Bioavailability decreased. Efavirenz shifted methadone concentration-miosis curves leftward and upward. Efavirenz induced hepatocyte CYP2B6 and CYP3A4 expression, activity, and methadone N-demethylation. Results show that efavirenz coinduced hepatic CYP2B6 and CYP3A4/5, coinduced hepatic and intestinal CYP3A4/5, and coinduced gastrointestinal CYP3A4/5 and efflux transporters. Methadone disposition was most consistent with efavirenz induction of hepatic CYP2B6-mediated methadone N-demethylation. Efavirenz may alter methadone pharmacodynamics.


Assuntos
Benzoxazinas/sangue , Benzoxazinas/farmacocinética , Metadona/sangue , Metadona/farmacocinética , Adolescente , Adulto , Alcinos , Hidrocarboneto de Aril Hidroxilases/metabolismo , Benzoxazinas/farmacologia , Estudos Cross-Over , Ciclopropanos , Citocromo P-450 CYP2B6 , Citocromo P-450 CYP3A/metabolismo , Interações Medicamentosas/fisiologia , Feminino , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Humanos , Masculino , Metadona/farmacologia , Oxirredutases N-Desmetilantes/metabolismo , Adulto Jovem
4.
Epidemiol Infect ; 140(3): 500-9, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21554781

RESUMO

Economic analyses of cholera immunization programmes require estimates of the costs of cholera. The Diseases of the Most Impoverished programme measured the public, provider, and patient costs of culture-confirmed cholera in four study sites with endemic cholera using a combination of hospital- and community-based studies. Families with culture-proven cases were surveyed at home 7 and 14 days after confirmation of illness. Public costs were measured at local health facilities using a micro-costing methodology. Hospital-based studies found that the costs of severe cholera were US$32 and US$47 in Matlab and Beira. Community-based studies in North Jakarta and Kolkata found that cholera cases cost between US$28 and US$206, depending on hospitalization. Patients' cost of illness as a percentage of average monthly income were 21% and 65% for hospitalized cases in Kolkata and North Jakarta, respectively. This burden on families is not captured by studies that adopt a provider perspective.


Assuntos
Cólera/economia , Cólera/epidemiologia , Efeitos Psicossociais da Doença , Doenças Endêmicas/economia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Índia , Indonésia , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
6.
Clin Pharmacol Ther ; 84(4): 497-505, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19238655

RESUMO

Ritonavir diminishes methadone plasma concentrations, an effect attributed to CYP3A induction, but the actual mechanisms are unknown. We determined ritonavir effects on stereoselective methadone pharmacokinetics and clinical effects (pupillary miosis) in healthy human immunodeficiency virus-negative volunteers. Subjects received intravenous plus oral (deuterium-labeled) racemic methadone after no ritonavir, short-term (3-day) ritonavir, and steady-state ritonavir. Acute and steady-state ritonavir, respectively, caused 1.5- and 2-fold induction of systemic and apparent oral R- and S-methadone clearances. Ritonavir increased renal clearance 40-50%, and stereoselectively (S > R) increased hepatic methadone N-demethylation 50-80%, extraction twofold, and clearance twofold. Bioavailability was unchanged despite significant inhibition of intestinal P-glycoprotein. Intestinal and hepatic CYP3A was inhibited > 70%. Ritonavir shifted methadone plasma concentration-miosis curves leftward and upward. Rapid ritonavir induction of methadone clearance results from increased renal clearance and induced hepatic metabolism. Induction of methadone metabolism occurred despite profound CYP3A inhibition, suggesting no role for CYP3A in clinical methadone metabolism and clearance. Ritonavir may alter methadone pharmacodynamics.


Assuntos
Citocromo P-450 CYP3A/fisiologia , Inibidores da Protease de HIV/farmacologia , Metadona/farmacocinética , Entorpecentes/farmacocinética , Ritonavir/farmacologia , Adulto , Área Sob a Curva , Disponibilidade Biológica , Estudos Cross-Over , Inibidores do Citocromo P-450 CYP3A , Relação Dose-Resposta a Droga , Interações Medicamentosas , Feminino , Inibidores da Protease de HIV/farmacocinética , Humanos , Masculino , Metadona/farmacologia , Entorpecentes/farmacologia , Pupila/efeitos dos fármacos , Ritonavir/farmacocinética , Estereoisomerismo
7.
Clin Pharmacol Ther ; 84(4): 506-12, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19238656

RESUMO

Ritonavir diminishes methadone plasma concentrations, an effect attributed to CYP3A induction, but the actual mechanisms are unknown. We determined short-term (2-day) and steady-state (2-week) ritonavir effects on intestinal and hepatic CYP3A4/5 (probed with intravenous (IV) and oral alfentanil (ALF) and with miosis) and P-glycoprotein (P-gp) (fexofenadine), and on methadone pharmacokinetics and pharmacodynamics in healthy volunteers. Acute ritonavir increased the area under the concentration-time curve (AUC)(0-infinity)/dose ratio (ritonavir/control) for oral ALF 25-fold. Steady-state ritonavir increased the AUC(0-Infinity)/dose ratio for IV and oral ALF 4- and 10-fold, respectively; reduced hepatic extraction (from 0.26 to 0.07) and intestinal extraction (from 0.51 to 0); and increased bioavailability (from 37 to 95%). Acute ritonavir inhibits first-pass CYP3A > 96%. Chronic ritonavir inhibits hepatic CYP3A (> 70%) and first-pass CYP3A (> 90%). Acute and steady-state ritonavir increased the fexofenadine AUC(0-infinity) 2.8- and 1.4-fold, respectively, suggesting P-gp inhibition. Steady-state compared with acute ritonavir caused mild apparent induction of P-gp and hepatic CYP3A, but net inhibition still predominated. Ritonavir inhibited both intestinal and hepatic CYP3A and drug transport. ALF miosis noninvasively determined CYP3A inhibition by ritonavir.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Citocromo P-450 CYP3A/fisiologia , Inibidores da Protease de HIV/farmacologia , Metadona/farmacocinética , Entorpecentes/farmacocinética , Ritonavir/farmacologia , Adulto , Alfentanil/administração & dosagem , Alfentanil/sangue , Alfentanil/farmacocinética , Área Sob a Curva , Disponibilidade Biológica , Estudos Cross-Over , Inibidores do Citocromo P-450 CYP3A , Relação Dose-Resposta a Droga , Interações Medicamentosas , Feminino , Inibidores da Protease de HIV/farmacocinética , Humanos , Intestinos/enzimologia , Fígado/enzimologia , Masculino , Metadona/farmacologia , Entorpecentes/farmacologia , Pupila/efeitos dos fármacos , Ritonavir/farmacocinética , Estereoisomerismo , Terfenadina/administração & dosagem , Terfenadina/análogos & derivados , Terfenadina/sangue , Terfenadina/farmacocinética
8.
Clin Pharmacol Ther ; 82(4): 410-26, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17554244

RESUMO

The hepatic and first-pass cytochrome P4503A (CYP3A) probe alfentanil (ALF) is also metabolized in vitro by CYP3A5. Human hepatic microsomal ALF metabolism is higher in livers with at least one CYP3A5*1 allele and higher CYP3A5 protein content, compared with CYP3A5*3 homozygotes with little CYP3A5. The influence of CYP3A5 genotype on ALF pharmacokinetics and pharmacodynamics was studied, and compared to midazolam (MDZ), another CYP3A probe. Healthy volunteers (58 men, 41 women) were genotyped for CYP3A5 *1, *3, *6, and *7 alleles. They received intravenous MDZ then ALF, and oral MDZ and ALF the next day. Plasma MDZ and ALF concentrations were determined by mass spectrometry. Dark-adapted pupil diameters were determined coincident with blood sampling. In CYP3A5(*)3/(*)3 (n=62), (*)1/(*)3 (n=28), and (*)1/(*)1 (n=8) genotypes, systemic clearances of ALF were 4.6+/-1.8, 4.8+/-1.7, and 3.9+/-1.7 ml/kg/min and those of MDZ were 7.8+/-2.3, 7.7+/-2.3, and 6.0+/-1.4 ml/kg/min, respectively (not significant), and apparent oral clearances were 11.8+/-7.2, 13.3+/-6.1, and 12.6+/-8.2 ml/kg/min for ALF and 35.2+/-19.0, 36.4+/-15.7, and 29.4+/-9.3 ml/kg/min for MDZ (not significant). Clearances were not different between African Americans (n=25) and Whites (n=68), or between CYP3A5 genotypes within African Americans. ALF pharmacodynamics was not different between CYP3A5 genotypes. There was consistent concordance between ALF and MDZ, in clearances and extraction ratios. Thus, in a relatively large cohort of healthy subjects with constitutive CYP3A activity, CYP3A5 genotype had no effect on the systemic or apparent oral clearances, or pharmacodynamics, of the CYP3A probes ALF and MDZ, despite affecting their hepatic microsomal metabolism.


Assuntos
Alfentanil/farmacocinética , Sistema Enzimático do Citocromo P-450/genética , Midazolam/farmacocinética , Polimorfismo Genético , Administração Oral , Adulto , Negro ou Afro-Americano/genética , Alfentanil/administração & dosagem , Alfentanil/efeitos adversos , Alfentanil/sangue , Biomarcadores/metabolismo , Citocromo P-450 CYP3A , Sistema Enzimático do Citocromo P-450/metabolismo , Feminino , Frequência do Gene , Genótipo , Hispânico ou Latino/genética , Humanos , Injeções Intravenosas , Masculino , Midazolam/administração & dosagem , Midazolam/sangue , Pessoa de Meia-Idade , Miose/induzido quimicamente , Fenótipo , Pupila/efeitos dos fármacos , Valores de Referência , Especificidade por Substrato , População Branca/genética
9.
Br J Gen Pract ; 55(514): 378-83, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15904557

RESUMO

BACKGROUND: Multiple sclerosis (MS) is a common cause of chronic progressive neurological disability where reduction in quality of life is an important feature. Many GPs have MS patients with a range of disabilities. Little is known about the supply of medical and community services and how this compares with demand. AIM: We aim to describe a community based sample of MS patients and investigate how disease characteristics, benefits, services accessed and perceived needs relate to sense of wellbeing. DESIGN: Cross-sectional survey. SETTING: Participants were recruited from a representative network of 30 GP practices across Northern Ireland. METHOD: MS patients answered a professionally administered questionnaire and agreed to their medical records being examined. Information was collected about their medical condition, sociodemographic characteristics, receipt of benefits and services, perceived needs and sense of wellbeing. RESULTS: Of the 149 participants, 23% were mildly affected (Kurtzke's Expanded Disability Status Scale [EDSS] 0-4.5), 41% were moderately disabled (EDSS 5.0-6.5) and 36% were severely disabled (EDSS 7.0-9.5). Disability was related to employment, receipt of benefits and services. Physiotherapy was a commonly perceived need. Other perceived needs differed between the moderately and severely disabled groups. Scores relating to wellbeing were related to disability and perceived needs. CONCLUSIONS: The relationship between use of medical and community services and disability is important for planning service provision. We have shown that perceived needs are related to wellbeing. In a progressive illness these developing needs could be anticipated.


Assuntos
Medicina de Família e Comunidade/estatística & dados numéricos , Esclerose Múltipla/terapia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Atitude Frente a Saúde , Enfermagem em Saúde Comunitária/estatística & dados numéricos , Estudos Transversais , Feminino , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação das Necessidades , Irlanda do Norte , Modalidades de Fisioterapia/estatística & dados numéricos , Qualidade de Vida , Cuidados Intermitentes
10.
Parasitology ; 124(Pt 4): 423-34, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12003066

RESUMO

Life-history attributes of the capsalid monogenean Benedenia lutjani, a parasite of Lutjanus carponotatus from the Great Barrier Reef, Queensland, Australia, were investigated from experimental infections. Oncomiracidia of B. lutjani invaded and attached at any site on the fish, but more commonly invaded body surfaces. Immature specimens then migrated to the pelvic fins. Development of the reproductive organs of B. lutjani corresponded with migratory movements on the host. Parasite aggregation on the pelvic fins coincided with the development of functional male reproductive organs and some protandrous worms that possessed a vagina appeared to be inseminated. Migration to, and aggregation on, the branchiostegal membranes (membranous folds posterior to the opercula) coincided with the onset of sexual maturity and commencement of egg production by parasites. The rate of parasite development and the timing of migratory events on the host were influenced by water temperature. All specimens of B. lutjani reached sexual maturity between 12 and 14 days p.i. at 24 degrees C and between 8 and 10 days p.i. at 27 degrees C. Anterior hamuli grew continually during a 16-day experiment at 27 degrees C and 25-day experiment at 23 degrees C and their length appeared to provide a suitable index to estimate parasite age. The possible adaptive significance of the migratory behaviour, site-specificity and its link with changes in parasite development are discussed.


Assuntos
Peixes/parasitologia , Trematódeos/fisiologia , Infecções por Trematódeos/parasitologia , Infecções por Trematódeos/veterinária , Animais , Doenças dos Peixes/parasitologia , Brânquias/parasitologia , Interações Hospedeiro-Parasita , Larva/crescimento & desenvolvimento , Movimento , Queensland , Trematódeos/crescimento & desenvolvimento
11.
Inorg Chem ; 40(22): 5596-602, 2001 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-11599959

RESUMO

(1R,2R-Diaminocyclohexane)oxalatoplatinum(II) (oxaliplatin) is a third-generation platinum anticancer compound that produces the same type of inter- and intrastrand DNA cross-links as cisplatin. In combination with 5-fluorouracil, oxaliplatin has been recently approved in Europe, Asia, and Latin America for the treatment of metastatic colorectal cancer. We present here the crystal structure of an oxaliplatin adduct of a DNA dodecanucleotide duplex having the same sequence as that previously reported for cisplatin (Takahara, P. M.; Rosenzweig, A. C.; Frederick, C. A.; Lippard, S. J. Nature 1995, 377, 649-652). Pt-MAD data were used to solve this first X-ray structure of a platinated DNA duplex derived from an active platinum anticancer drug other than cisplatin. The overall geometry and crystal packing of the complex, refined to 2.4 A resolution, are similar to those of the cisplatin structure, despite the fact that the two molecules crystallize in different space groups. The platinum atom of the [Pt(R,R-DACH)](2+) moiety forms a 1,2-intrastrand cross-link between two adjacent guanosine residues in the sequence 5'-d(CCTCTGGTCTCC), bending the double helix by approximately 30 degrees toward the major groove. Both end-to-end and end-to-groove packing interactions occur in the crystal lattice. The latter is positioned in the minor groove opposite the platinum cross-link. A novel feature of the present structure is the presence of a hydrogen bond between the pseudoequatorial NH hydrogen atom of the (R,R)-DACH ligand and the O6 atom of the 3'-G of the platinated d(GpG) lesion. This finding provides structural evidence for the importance of chirality in mediating the interaction between oxaliplatin and duplex DNA, calibrating previously published models used to explain the reactivity of enantiomerically pure vicinal diamine platinum complexes with DNA in solution. It also provides a new kind of chiral recognition between an enantiomerically pure metal complex and the DNA double helix.


Assuntos
Antineoplásicos/química , Reagentes de Ligações Cruzadas/química , Adutos de DNA/química , DNA/química , Guanosina/química , Compostos Organoplatínicos/química , Cristalografia por Raios X , Conformação de Ácido Nucleico , Oligonucleotídeos/química , Oxaliplatina
12.
Proc Natl Acad Sci U S A ; 98(17): 9545-50, 2001 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-11493685

RESUMO

Overexpression of the zinc enzyme carbonic anhydrase (CA; EC ) XII is observed in certain human cancers. This bitopic membrane protein contains an N-terminal extracellular catalytic domain, a membrane-spanning alpha-helix, and a small intracellular C-terminal domain. We have determined the three-dimensional structure of the extracellular catalytic domain of human CA XII by x-ray crystallographic methods at 1.55-A resolution. The structure reveals a prototypical CA fold; however, two CA XII domains associate to form an isologous dimer, an observation that is confirmed by studies of the enzyme in solution. The identification of signature GXXXG and GXXXS motifs in the transmembrane sequence that facilitate helix-helix association is additionally consistent with dimeric architecture. The dimer interface is situated so that the active site clefts of each monomer are clearly exposed on one face of the dimer, and the C termini are located together on the opposite face of the dimer to facilitate membrane interaction. The amino acid composition of the active-site cleft closely resembles that of the other CA isozymes in the immediate vicinity of the catalytic zinc ion, but differs in the region of the nearby alpha-helical "130's segment." The structure of the CA XII-acetazolamide complex is also reported at 1.50-A resolution, and prospects for the design of CA XII-specific inhibitors of possible chemotherapeutic value are discussed.


Assuntos
Anidrases Carbônicas/química , Proteínas de Membrana/química , Proteínas de Neoplasias/química , Acetazolamida/química , Acetazolamida/farmacologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Sítios de Ligação , Inibidores da Anidrase Carbônica/química , Inibidores da Anidrase Carbônica/farmacologia , Catálise , Cristalografia por Raios X , Dimerização , Desenho de Fármacos , Humanos , Camundongos , Dados de Sequência Molecular , Conformação Proteica , Ratos , Proteínas Recombinantes de Fusão/química , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Zinco/química
13.
J Am Chem Soc ; 123(5): 827-38, 2001 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-11456616

RESUMO

The oxidation of methane to methanol is performed at carboxylate-bridged dinuclear iron centers in the soluble methane monooxygenase hydroxylase (MMOH). Previous structural studies of MMOH, and the related R2 subunit of ribonucleotide reductase, have demonstrated the occurrence of carboxylate shifts involving glutamate residues that ligate the catalytic iron atoms. These shifts are thought to have important mechanistic implications. Recent kinetic and theoretical studies have also emphasized the importance of hydrogen bonding and pH effects at the active site. We report here crystal structures of MMOH from Methylococcus capsulatus (Bath) in the diiron(II), diiron(III), and mixed-valent Fe(II)Fe(III) oxidation states, and at pH values of 6.2, 7.0, and 8.5. These structures were investigated in an effort to delineate the range of possible motions at the MMOH active site and to identify hydrogen-bonding interactions that may be important in understanding catalysis by the enzyme. Our results present the first view of the diiron center in the mixed-valent state, and they indicate an increased lability for ferrous ions in the enzyme. Alternate conformations of Asn214 near the active site according to redox state and a distortion in one of the alpha-helices adjacent to the metal center in the diiron(II) state have also been identified. These changes alter the surface of the protein in the vicinity of the catalytic core and may have implications for small-molecule accessibility to the active site and for protein component interactions in the methane monooxygenase system. Collectively, these results help to explain previous spectroscopic observations and provide new insight into catalysis by the enzyme.


Assuntos
Ferro/metabolismo , Methylococcus capsulatus/enzimologia , Oxigenases/química , Sítios de Ligação , Cristalografia por Raios X , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Modelos Moleculares , Oxigenases/isolamento & purificação , Oxigenases/metabolismo , Conformação Proteica
16.
Biochemistry ; 40(12): 3476-82, 2001 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-11297413

RESUMO

To investigate the role of protein cavities in facilitating movement of the substrates, methane and dioxygen, in the soluble methane monooxygenase hydroxylase (MMOH), we determined the X-ray structures of MMOH from Methylococcus capsulatus (Bath) cocrystallized with dibromomethane or iodoethane, or by using crystals pressurized with xenon gas. The halogenated alkanes bind in two cavities within the alpha-subunit that extend from one surface of the protein to the buried dinuclear iron active site. Two additional binding sites were located in the beta-subunit. Pressurization of two crystal forms of MMOH with xenon resulted in the identification of six binding sites located exclusively in the alpha-subunit. These results indicate that hydrophobic species bind preferentially in preexisting cavities in MMOH and support the hypothesis that such cavities may play a functional role in sequestering and enhancing the availability of the physiological substrates for reaction at the active site.


Assuntos
Alcanos/química , Hidrocarbonetos Bromados/química , Hidrocarbonetos Iodados/química , Oxigenases/química , Xenônio/química , Sítios de Ligação , Simulação por Computador , Cristalização , Cristalografia por Raios X , Congelamento , Methylococcus capsulatus/enzimologia , Modelos Moleculares , Pressão , Estrutura Secundária de Proteína , Solubilidade , Especificidade por Substrato
17.
J Anim Sci ; 78(7): 1726-31, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10907813

RESUMO

Site-segregated early weaning (SSEW) refers to the practice of weaning pigs from the sow at an early age and placing them in a nursery that is physically isolated from the breeding herd. An experiment involving 369 pigs was conducted at the Prairie Swine Center to investigate the impact of SSEW on pig performance when the herd of origin has a high health status and when housing and management conditions are kept as similar as possible across weaning regime. Three treatments were compared: weaning at 21+/-3 d and keeping the pigs on-site in an all-in-all-out nursery room (Control), weaning at 12+/-2 d of age and keeping the pigs on-site in a separate but identical all-in-all-out nursery room (OSEW), or weaning at 12+/-2 d of age and moving the pigs off-site to an all-in-all-out nursery room located 16 km from the Center (SSEW). Ventilation, feed, penning, feeders, and drinkers were kept as similar as possible for all treatments. Off-site weaning improved 56-d body weight (P < .05) by 12.5 and 8.3% compared with OSEW and Control, respectively. The improvement appeared to be the result of improvements primarily in feed intake but also due to enhanced efficiency of nutrient utilization. This experiment confirms that SSEW results in significant improvements in 56-d weights, even when the herd of origin has a relatively high health status.


Assuntos
Criação de Animais Domésticos/métodos , Suínos/crescimento & desenvolvimento , Envelhecimento , Animais , Ambiente Controlado , Nível de Saúde , Desmame
18.
Eur J Biochem ; 267(8): 2174-85, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10759840

RESUMO

The soluble methane monooxygenase (sMMO) hydroxylase is a prototypical member of the class of proteins with non-heme carboxylate-bridged diiron sites. The sMMO subclass of enzyme systems has several distinguishing characteristics, including the ability to catalyze hydroxylation or epoxidation chemistry, a multisubunit hydroxylase containing diiron centers in its alpha subunits, and the requirement of a coupling protein for optimal activity. Sequence homology alignment of known members of the sMMO family was performed in an effort to identify protein regions giving rise to these unique features. DNA sequencing of the Methylococcus capsulatus (Bath) sMMO genes confirmed previously identified sequencing errors and corrected two additional errors, each of which was confirmed by at least one independent method. Alignments of homologous proteins from sMMO, phenol hydroxylase, toluene 2-, 3-, and 4-monooxygenases, and alkene monooxygenase systems revealed an interesting set of absolutely conserved amino-acid residues, including previously unidentified residues located outside the diiron active site of the hydroxylase. By mapping these residues on to the M. capsulatus (Bath) sMMO hydroxylase crystal structure, functional and structural roles were proposed for the conserved regions. Analysis of the active site showed a highly conserved hydrogen-bonding network on one side of the diiron cluster but little homology on the opposite side, where substrates are presumed to bind. It is suggested that conserved residues on the hydroxylase surface may be important for protein-protein interactions with the reductase and coupling ancillary proteins and/or serve as part of an electron-transfer pathway. A possible way by which binding of the coupling protein at the surface of the hydroxylase might transfer information to the diiron active site at the interior is proposed.


Assuntos
Genes Bacterianos , Methylococcus capsulatus/genética , Oxigenases/genética , Sequência de Aminoácidos , Sítios de Ligação , Clonagem Molecular , Sequência Conservada , Transporte de Elétrons , Ligação de Hidrogênio , Ferro/química , Metaloproteínas/química , Methylococcus capsulatus/enzimologia , Modelos Moleculares , Dados de Sequência Molecular , Complexos Multienzimáticos/química , Oxigenases/química , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Alinhamento de Sequência
19.
Stroke ; 31(1): 214-22, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10625740

RESUMO

BACKGROUND AND PURPOSE: Peri-infarct depolarizations (PIDs) that occur in ischemic boundary zones of the cerebral cortex of experimental animals have been shown to promote rather than simply to indicate the evolution of the lesion and are especially prominent in the rat. To study the influence of one factor, species, on PID incidence, we compared the frequency of PIDs in a primate species, the squirrel monkey, with that in the cat after middle cerebral artery occlusion. Plasma glucose was reviewed as a possible cause of interexperiment variability in the cat experiments. METHODS: In open-skull experiments under chloralose anesthesia, changes in cortical fluorescence believed to indicate NADH/NAD(+) redox state, as markers of PIDs, were recorded by serial imaging of the cortical surface in vivo for 4 hours after middle cerebral artery occlusion. RESULTS: Fluorescence transients occurred in squirrel monkeys at a frequency (mean+/-SD) of 0.7+/-0.8 hours(-1) (n=5), which was not significantly less than in that observed in cats (1.3+/-1.6 hours(-1), n=8). Data from the cat experiments indicated a relationship between number of transients (dependent) and plasma glucose, with a striking increase in PID frequency in association with values of mean postocclusion plasma glucose <4.1 mmol/L (Mann-Whitney U=15.0, P=0.034); this observation agrees well with other published findings. CONCLUSIONS: Transient changes in fluorescence strongly suggestive of peri-infarct depolarizations, either transient or terminal, occur and propagate in the ischemic cerebral cortex of a nonhuman primate. The results also suggest that the relationship of frequency of peri-infarct depolarizations with plasma glucose requires further examination, to confirm the finding and to determine a safe lower limit for a target range for control of plasma glucose if insulin is used in the management of patients with cerebral ischemia.


Assuntos
Glicemia/metabolismo , Isquemia Encefálica/metabolismo , Isquemia Encefálica/fisiopatologia , Depressão Alastrante da Atividade Elétrica Cortical , Potenciais de Ação , Animais , Gatos , Infarto Cerebral/metabolismo , Infarto Cerebral/patologia , Infarto Cerebral/fisiopatologia , Fluorescência , NAD/metabolismo , Oxirredução , Ratos , Saimiri
20.
J Psychiatr Ment Health Nurs ; 7(3): 259-68, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11249320

RESUMO

This article explores the proportion of work time psychiatric nurses spend in potentially psychotherapeutic one-to-one communication with patients. Twenty staff nurses from three acute admission wards in a psychiatric hospital in Northern Ireland were observed. The time spent in a selection of routine activities was recorded using a specially developed observation system Nurses' Daily Activity Recording System (NURDARS). The main findings were: (i) less than half of the working day (42.7%) was spent in patient contact, and (ii) the proportion of work time which was devoted to potentially psychotherapeutic interaction with patients was very small (6.75%). The implications and limitations of the study are discussed and suggestions are made for the management and practice of psychiatric nursing, for the education of psychiatric nurses, and for further research.


Assuntos
Agendamento de Consultas , Relações Enfermeiro-Paciente , Enfermagem Psiquiátrica/métodos , Enfermagem Psiquiátrica/organização & administração , Gerenciamento do Tempo , Doença Aguda , Hospitais Psiquiátricos , Humanos , Irlanda do Norte , Recursos Humanos de Enfermagem Hospitalar
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