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2.
Respir Res ; 23(1): 305, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36352422

RESUMO

BACKGROUND: The club cell secretory protein (CC16) has anti-inflammatory and antioxidant effects and is a potential early biomarker of lung damage. The CC16 single nucleotide polymorphism (SNP) rs3741240 risk allele (A) has been inconsistently linked to asthma; other tagging SNPs in the gene have not been explored. The aim was to determine whether CC16 tagging polymorphisms are associated with adult asthma, asthma subtypes or asthma control in the Agricultural Lung Health Study (ALHS). METHODS: The ALHS is an asthma case-control study nested in the Agricultural Health Study cohort. Asthma cases were individuals with current doctor diagnosed asthma, likely undiagnosed asthma, or asthma-COPD overlap defined by questionnaire. We also examined asthma subtypes and asthma control. Five CC16 tagging SNPs were imputed to 1000 Genomes Integrated phase 1 reference panel. Logistic regression was used to estimate associations between CC16 SNPs and asthma outcomes adjusted for covariates. RESULTS: The sample included 1120 asthma cases and 1926 controls of European ancestry, with a mean age of 63 years. The frequency of the risk genotype (AA) for rs3741240 was 12.5% (n = 382). CC16 rs3741240 was not associated with adult asthma outcomes. A tagging SNP in the CC16 gene, rs12270961 was associated with uncontrolled asthma (n = 208, ORadj= 1.4, 95% CI 1.0, 1.9; p = 0.03). CONCLUSION: This study, the largest study to investigate associations between CC16 tagging SNPs and asthma phenotypes in adults, did not confirm an association of rs3741240 with adult asthma. A tagging SNP in CC16 suggests a potential relationship with asthma control.


Assuntos
Asma , Uteroglobina , Humanos , Asma/diagnóstico , Asma/epidemiologia , Asma/genética , Estudos de Casos e Controles , Pulmão , Polimorfismo de Nucleotídeo Único/genética , Uteroglobina/genética , Adulto
3.
J Crohns Colitis ; 13(9): 1186-1200, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31220227

RESUMO

Intestinal fibrosis and stenosis are common complications of Crohn's disease [CD], frequently requiring surgery. Anti-inflammatory strategies can only partially prevent fibrosis; hence, anti-fibrotic therapies remain an unmet clinical need. Oxysterols are oxidised cholesterol derivatives with important roles in various biological processes. The enzyme cholesterol 25-hydroxylase [CH25H] converts cholesterol to 25-hydroxycholesterol [25-HC], which modulates immune responses and oxidative stress. In human intestinal samples from CD patients, we found a strong correlation of CH25H mRNA expression with the expression of fibrosis markers. We demonstrate reduced intestinal fibrosis in mice deficient for the CH25H enzyme, using the sodium dextran sulphate [DSS]-induced chronic colitis model. Additionally, using a heterotopic transplantation model of intestinal fibrosis, we demonstrate reduced collagen deposition and lower concentrations of hydroxyproline in CH25H knockouts. In the heterotopic transplant model, CH25H was expressed in fibroblasts. Taken together, our findings indicate an involvement of oxysterol synthesis in the pathogenesis of intestinal fibrosis.


Assuntos
Intestinos/patologia , Oxisteróis/metabolismo , Esteroide Hidroxilases/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Colite/induzido quimicamente , Colite/enzimologia , Doença de Crohn/complicações , Doença de Crohn/patologia , Sulfato de Dextrana/farmacologia , Modelos Animais de Doenças , Feminino , Fibrose , Humanos , Intestinos/enzimologia , Intestinos/transplante , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Esteroide Hidroxilases/deficiência
4.
J Neurosci ; 38(50): 10644-10656, 2018 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-30355637

RESUMO

A restricted lesion of the hand area in the primary motor cortex (M1) leads to a deficit of contralesional manual dexterity, followed by an incomplete functional recovery, accompanied by plastic changes in M1 itself and in other cortical areas on both hemispheres. Using the marker SMI-32 specific to pyramidal neurons in cortical layers III and V, we investigated the impact of a focal unilateral M1 lesion (hand representation) on the rostral part (F6) and caudal part (F3) of the supplementary motor area (SMA) in both hemispheres in nine adult macaque monkeys compared with four intact control monkeys. The M1 lesion induced a consistent interhemispheric asymmetry in density of SMI-32-positive neurons in F3 layer V (statistically significant in 8 of 9 lesioned monkeys), highly correlated with the lesion volume and with the duration of functional recovery, but not with the extent of functional recovery itself. Such interhemispheric asymmetry was neither present in the intact monkeys, as expected, nor in F6 in all monkeys. In addition, the M1 lesion also impacted on the basal dendritic arborization of F3 layer V neurons. Neuronal density was clearly less affected by the M1 lesion in F3 layer III compared with layer V. We interpret the remote effect of M1 lesion onto the density of SMI-32-positive neurons and dendritic arborization in the SMAs bilaterally as the consequence of multiple factors, such as changes of connectivity, diaschisis and various mechanisms involved in cortical plasticity underlying the functional recovery from the M1 lesion.SIGNIFICANCE STATEMENT The motor system of macaque monkeys, in addition to be similarly organized as in humans, is a good candidate to study the impact of a focal lesion of the main contributor to voluntary movements, the primary motor cortex (M1), on non-primary motor cortical areas also involved in manual dexterity, both at behavioral and structural levels. Our results show that a unilateral permanent lesion of M1 hand area in nine monkeys affects the interhemispheric balance of the number of SMI-32-positive pyramidal neurons in the cortical layer V of the supplementary motor area, in a way strongly correlated to the lesion volume and duration of the incomplete functional recovery.


Assuntos
Lateralidade Funcional/fisiologia , Córtex Motor/patologia , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Desempenho Psicomotor/fisiologia , Fatores Etários , Animais , Craniotomia/métodos , Macaca fascicularis , Macaca mulatta , Córtex Motor/citologia
6.
Br J Cancer ; 110(9): 2369-77, 2014 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-24619077

RESUMO

BACKGROUND: Oncogenic human papillomavirus (HPV) has been hypothesised as a risk factor for oesophageal squamous cell carcinoma (OSCC), but aetiological research has been limited by the varying methodology used for establishing HPV prevalence. The aims of this systematic review and meta-analysis were to estimate the prevalence of HPV DNA detected in OSCC tumours and the influence of study characteristics. METHODS: Study-level estimates of overall and type-specific HPV prevalence were meta-analysed to obtain random-effects summary estimates. RESULTS: This analysis included 124 studies with a total of 13 832 OSCC cases. The average HPV prevalence (95% confidence interval) among OSCC cases was 0.277 (0.234, 0.320) by polymerase chain reaction; 0.243 (0.159, 0.326) by in situ hybridisation; 0.304 (0.185, 0.423) by immunohistochemistry; 0.322 (0.154, 0.490) by L1 serology; and 0.176 (0.061, 0.292) by Southern/slot/dot blot. The highest HPV prevalence was found in Africa and Asia, notably among Chinese studies from provinces with high OSCC incidence rates. CONCLUSIONS: Future research should focus on quantifying HPV in OSCC cases using strict quality control measures, as well as determining the association between HPV and OSCC incidence by conducting large, population-based case-control studies. Such studies will provide a richer understanding of the role of HPV in OSCC aetiology.


Assuntos
Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/virologia , Neoplasias Esofágicas/epidemiologia , Neoplasias Esofágicas/virologia , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/epidemiologia , Carcinoma de Células Escamosas do Esôfago , Humanos , Prevalência
7.
Spinal Cord ; 51(11): 828-33, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23999106

RESUMO

STUDY DESIGN: This was a prospective cohort study. OBJECTIVES: The objective was to describe the incidence, prevalence, characteristics of pressure ulcers (PUs) and the association with specific patient characteristics in a consecutive sample of in-patients with a spinal cord injury (SCI). SETTING: An acute care and rehabilitation clinic specialized in SCIs in Switzerland. METHODS: The presence and characteristics of PUs for all adult patients with a SCI admitted to the clinic from 1 September 2009 to 28 February 2010 were recorded on a daily basis during their complete hospitalization. Risk factors were analyzed in univariate and multivariate logistic regression models. RESULTS: A total of 185 patients were included in the study and observed for the entirety of their hospitalization. The prevalence of at least one PU was 49.2% in all patients, compared with 25.4% in the group of patients admitted without PUs. The incidence was 2.2 per person and year. In 91 patients, a total of 219 PUs were observed. PUs were most frequently located on the foot (36.1%), and the coccyx/sacrum (15.1%). The risk for occurrence of a PU increased with age (odds ratio (OR)=1.04) and post SCI (OR=1.03). In the multivariate analyses, the risk for PUs was lower for patients with the American Spinal Injury Association (ASIA) Impairment Scale (AIS) of C or D (ORC=0.25, ORD=0.28) compared with patients with an AIS of A. CONCLUSION: Using a daily documentation system, PUs were detected as a frequent complication of SCIs. Completeness of injury, age and time since injury were significant risk factors for PUs. The foot was a region at high risk for PUs.


Assuntos
Hospitalização/estatística & dados numéricos , Úlcera por Pressão/epidemiologia , Traumatismos da Medula Espinal/epidemiologia , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Atividade Motora , Úlcera por Pressão/fisiopatologia , Prevalência , Estudos Prospectivos , Fatores de Risco , Traumatismos da Medula Espinal/reabilitação
8.
Spinal Cord ; 51(1): 40-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22890418

RESUMO

STUDY DESIGN: Cross-sectional validation study. OBJECTIVES: To develop and validate a self-report version of the Spinal Cord Independence Measure (SCIM III). SETTING: Two SCI rehabilitation facilities in Switzerland. METHODS: SCIM III comprises 19 questions on daily tasks with a total score between 0 and 100 and subscales for 'self-care', 'respiration & sphincter management' and 'mobility'. A self-report version (SCIM-SR) was developed by expert discussions and pretests in individuals with spinal cord injury (SCI) using a German translation. A convenience sample of 99 inpatients with SCI was recruited. SCIM-SR data were analyzed together with SCIM III data obtained from attending health professionals. RESULTS: High correlations between SCIM III and SCIM-SR were observed. Pearson's r for the total score was 0.87 (95% confidence interval (CI) 0.82-0.91), for the subscales self-care 0.87 (0.81-0.91); respiration & sphincter management 0.81 (0.73-0.87); and mobility 0.87 (0.82-0.91). Intraclass correlations were: total score 0.90 (95% CI 0.85-0.93); self-care 0.86 (0.79-0.90); respiration & sphincter management 0.80 (0.71-0.86); and mobility 0.83 (0.76-0.89). Bland-Altman plots showed that patients rated their functioning higher than professionals, in particular for mobility. The mean difference between SCIM-SR and SCIM III for the total score was 5.14 (point estimate 95% CI 2.95-7.34), self-care 0.89 (0.19-1.59), respiration & sphincter management 1.05 (0.18-2.28 ) and mobility 3.49 (2.44-4.54). Particularly patients readmitted because of pressure sores rated their independence higher than attending professionals. CONCLUSION: Our results support the criterion validity of SCIM-SR. The self-report version may facilitate long-term evaluations of independence in persons with SCI in their home situation.


Assuntos
Vida Independente/psicologia , Traumatismos da Medula Espinal/psicologia , Atividades Cotidianas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Avaliação da Deficiência , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Vida Independente/estatística & dados numéricos , Idioma , Masculino , Pessoa de Meia-Idade , Centros de Reabilitação , Reprodutibilidade dos Testes , Autorrelato , Fatores Socioeconômicos , Inquéritos e Questionários , Suíça , Resultado do Tratamento , Adulto Jovem
9.
Biotechnol Bioeng ; 93(1): 28-39, 2006 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-16136589

RESUMO

A novel reactive perstraction system has been developed based on liquid-core capsules, involving an enzyme-catalyzed reaction coupled with simultaneous in situ product recovery. Lipase-catalyzed reactions, hydrolysis of triprionin and nitrophenyl laurate, were selected to test the system and demonstrate the feasibility of immobilization of enzymes to the membranes of liquid-core capsules and the ability to extract hydrophobic products of the reaction within the capsule core. The lipase from Candida rugosa was immobilized to the microcapsules by adsorption and by covalent binding through activation with glutaraldehyde. In both cases improved temperature and operational stability were achieved. Both types of immobilization resulted in a basic shift of the pH optimum for activity, from 7.5 to 9.0. The presence of an organic phase within the capsule core allowed direct product separation and lead to a decrease in product inhibition of the lipase-catalyzed reaction.


Assuntos
Candida/enzimologia , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Lauratos/química , Lipase/química , Biotransformação , Cápsulas , Enzimas Imobilizadas/metabolismo , Proteínas Fúngicas/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Lauratos/metabolismo , Lipase/metabolismo
10.
Biotechnol Bioeng ; 91(2): 227-36, 2005 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-15915512

RESUMO

The activity of penicillin acylase has been studied in aqueous and organic solvents, as free enzyme as well as immobilized within the membrane of liquid-core capsules. The activity of the enzyme is inhibited by the accumulation of the products of the hydrolysis reaction, namely phenyl acetic acid (PAA). In order to overcome this inhibition a range of organic solvents were tested for use in in situ product recovery. Of these solvents dibutyl sebacate (DBS) was chosen due to the rapid extraction rate, the high logP and to facilitate capsule production. The extraction efficiency at pH 3.5 for PAA was >80% for phase ratios of >50% free solvent with partition coefficients of 8 and 0.7 for PAA and penicillin G (PenG), respectively, thereby showing that PAA could be selectively extracted at pH 3.5 and 25 degrees C. Liquid-core capsules containing DBS were shown to efficiently remove PAA selectively and the PAA could be effectively back-extracted and the capsules re-used in a three-stage process resulting in high product separation. Immobilization of penicillin acylase onto the capsule membranes resulted in increased operational stability of the enzyme and a very high enzyme activity. Over 53.3% of the PAA formed could be recovered in the capsule core with a concentration over sevenfold higher than in the aqueous phase. Higher extraction efficiencies could be obtained by varying the substrate concentration and number of capsules. The enzyme immobilized on capsules could be stored for over 4 months at pH 8 and 4 degrees C with no loss of activity. Over 80% of the initial activity could be recovered over five repeated batch cycles of the bioconversion process. The importance of capsular perstraction and reactive capsular perstraction has been clearly demonstrated.


Assuntos
Ácidos Dicarboxílicos/química , Compostos Orgânicos/química , Penicilina Amidase/química , Penicilina G/química , Fenilacetatos/química , Solventes/química , Ativação Enzimática , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Hidrólise , Fenilacetatos/isolamento & purificação
11.
Biotechnol Bioeng ; 87(6): 734-42, 2004 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-15329931

RESUMO

A novel perstraction system using liquid-core microcapsules for pesticide and herbicide removal from aqueous environments is proposed. The microcapsules contain an oil, dibutyl sebacate, surrounded by a hydrogel membrane. The extraction efficiency of the capsules was demonstrated with atrazine, methylparathion, ethylparathion, and 2,4-dichloro-phenoxyacetic acid. The results show that all of the tested compounds could be rapidly extracted, typically 75% extraction within 10 minutes using a capsule: liquid volume ratio of only 3.5% for ethylparathion, and that the rate of extraction increased with increasing hydrophobicity of the compound to be extracted. Higher rates of extraction could be achieved by changing the capsule: liquid volume ratio. The effect of different liquid core solvents, size of capsules, agitation rate, and treatment with complexing agents on the properties of the microcapsules and extraction rate were studied. Capsules of a diameter smaller than 0.800 mm show little external resistance to mass transfer. The main resistance to mass transfer of the pesticides/herbicides was found to reside in the hydrogel membrane composed of cross-linked alginate/polyacrylamide. Removal of divalent cations from the membrane by the addition of citrate, resulted in a 50% increase in the mass transfer coefficient, probably as a result of solubilization and exo-diffusion of alginate.


Assuntos
Fracionamento Químico/métodos , Ácidos Dicarboxílicos/química , Hidrogéis/química , Praguicidas/química , Praguicidas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Herbicidas/química , Herbicidas/isolamento & purificação , Cinética , Microesferas , Tamanho da Partícula , Ultrafiltração/métodos
12.
Biotechnol Bioeng ; 86(5): 563-72, 2004 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-15129440

RESUMO

A novel chemistry has been developed for the production of capsules composed of a hydrophobic liquid core surrounded by a cross-linked polyacrylamide/alginate membrane. These liquid-core capsules may be used in capsular perstraction for the removal of inhibitory products from bioprocesses and bioconversions. They have the advantage of having a high surface area to promote rapid mass transfer, while separation of the organic core phase from the aqueous environment by the capsule membrane prevents the formation of stable emulsions and potential problems associated with toxicity of the organic phase for microbial cells or enzymes. Monodisperse spherical liquid-core capsules of between 800 microm and 1.6 mm diameter, with high mechanical resistance, have been prepared by co-extrusion, using the jet break-up technique. Capsules produced from a solution of MBA/total monomer (5%) were found to be more elastic and have a higher burst force when exposed to chelating agents such as phosphate or citrate. The mechanical resistance was unaffected by buffer solutions in the pH range 4-9 and after sterilization at 121 degrees C for 20 min. Capsules having membranes composed of a copolymer of acrylamide and N-hydroxymethylacrylamide exhibited even higher mechanical stability toward chelating agents.


Assuntos
Resinas Acrílicas/química , Alginatos/química , Materiais Biocompatíveis/química , Biotecnologia/métodos , Cápsulas/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Reagentes de Ligações Cruzadas/química , Elasticidade , Dureza , Concentração de Íons de Hidrogênio , Teste de Materiais , Tamanho da Partícula , Solubilidade , Soluções
14.
Arch Biochem Biophys ; 385(1): 47-52, 2001 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11361025

RESUMO

Beta-carotene 15,15'-dioxygenase cleaves beta-carotene into two molecules of retinal and is the key enzyme in the metabolism of carotene to vitamin A. Although the enzyme has been known for more than 40 years, all attempts to purify the protein to homogeneity or to clone its gene have failed until recently, when the successful cloning and sequencing of cDNAs encoding enzymes with beta-carotene 15,15'-dioxygenase activity from Drosophila (J. von Lintig and K. Vogt, 2000, J. Biol. Chem. 275, 11915-11920) and chicken (A. Wyss et al., 2000, Biochem. Biophys. Res. Commun. 271, 334-336) were reported. Very soon it became clear, that we have cloned two members of a new family of carotenoid cleaving enzymes. Overall homologies are very high, certain amino acid stretches almost identical. Thus, beta-carotene 15,15'-dioxygenase can be considered as evolutionarily well conserved. These findings open up wide perspectives for further analysis of this important biosynthetic pathway, concerning basic and medical research as well as biotechnological aspects related to vitamin A supply, which are discussed here.


Assuntos
Oxigenases/química , Oxigenases/genética , Deficiência de Vitamina A/genética , Vitamina A/biossíntese , Vitamina A/genética , Sequência de Aminoácidos , Animais , DNA Complementar/metabolismo , Humanos , Modelos Químicos , Dados de Sequência Molecular , Oxigenases/biossíntese , Homologia de Sequência de Aminoácidos , Deficiência de Vitamina A/terapia , beta-Caroteno 15,15'-Mono-Oxigenase
15.
Biochem J ; 354(Pt 3): 521-9, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11237856

RESUMO

Beta,beta-carotene 15,15'-dioxygenase cleaves beta,beta-carotene into two molecules of retinal, and is the key enzyme in the metabolism of beta,beta-carotene to vitamin A. The enzyme has been known for more than 40 years, yet all attempts to purify the protein to homogeneity have failed. Recently, the successful cloning and sequencing of an enzyme with beta,beta-carotene 15,15'-dioxygenase activity from chicken, as well as from Drosophila, has been reported. Here, we describe in detail our attempt to enrich the chicken beta,beta-carotene 15,15'-dioxygenase to such an extent as to allow determination of partial amino acid sequences, which were then used to design degenerate oligonucleotides. Screening of a chicken duodenal expression library yielded a full-length clone containing a coding sequence of 1578 bp. Functional expression in Escherichia coli and in eukaryotic cell lines confirmed that we had cloned the first vertebrate dioxygenase that cleaves beta,beta-carotene at the central 15,15'-double bond. By performing a sequence homology search, the cDNA sequence of the mouse homologue was found as an expressed sequence tag (EST) in the gene bank. At the amino-acid level, the degree of homology between the chicken and mouse sequences is 81%. Thus beta,beta-carotene 15,15'-dioxygenase can be considered as being an enzyme that is evolutionarily rather well conserved. We established the expression pattern of beta,beta-carotene 15,15'-dioxygenase in chicken and mouse tissues with a combination of Northern blots and in situ hybridization. The mRNA for beta,beta-carotene 15,15'-dioxygenase was localized primarily in duodenal villi, as well as in liver and in tubular structures of lung and kidney. These new findings demonstrate that beta,beta-carotene 15,15'-dioxygenase is also expressed in epithelial structures, where it serves to provide the tissue-specific vitamin A supply.


Assuntos
Oxigenases/genética , Oxigenases/metabolismo , Sequência de Aminoácidos , Animais , Northern Blotting , Células CHO , Galinhas , Clonagem Molecular , Cricetinae , Células Epiteliais/metabolismo , Hibridização In Situ , Mucosa Intestinal/metabolismo , Camundongos , Dados de Sequência Molecular , Oxigenases/isolamento & purificação , RNA Mensageiro/biossíntese , Homologia de Sequência de Aminoácidos , Distribuição Tecidual , Transfecção , beta-Caroteno 15,15'-Mono-Oxigenase
16.
Growth Factors ; 18(2): 109-18, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11019782

RESUMO

In interleukin-3 (IL-3)-dependent PB-3c mast cells, the normally short-lived IL-3 mRNA is stabilized upon calcium-ionophore treatment or following v-H-ras induced oncogenesis. We compared the underlying stabilization mechanisms by analysing the response to the post-transcriptionally acting drugs cyclosporin A (CsA), FK506 and SB202190. Stable IL-3 transcripts in the PB-3c-derived tumour cell line V2D1 decayed in response to CsA and FK506, but not in response to SB202190. Transcripts stabilized by elevating intracellular calcium levels in PB-3c cells were destabilized in response to all three drugs. In PB-3c cells, six AUUUA pentamers within the AU-rich element were sufficient to confer responsiveness to calcium-ionophore and CsA treatment. In V2D1 tumour cells, sensitivity to CsA required additional nucleotides flanking these pentamers. Our data suggest that IL-3 mRNA stabilization by either calcium-dependent or oncogenic pathways involves different intracellular mechanisms.


Assuntos
Regiões 3' não Traduzidas/genética , Transformação Celular Neoplásica/genética , Interleucina-3/genética , RNA Mensageiro/metabolismo , Regiões 3' não Traduzidas/metabolismo , Sequência de Bases , Cálcio/farmacologia , Ciclosporina/farmacologia , Ionomicina/farmacologia , Dados de Sequência Molecular , Estabilidade de RNA/efeitos dos fármacos , RNA Mensageiro/genética
17.
Biochem Biophys Res Commun ; 271(2): 334-6, 2000 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-10799297

RESUMO

beta,beta-Carotene 15,15'-dioxygenase cleaves beta-carotene into two molecules of retinal and is therefore the key enzyme in beta-carotene metabolism to vitamin A. In the present study, it was possible to enrich the chicken beta,beta-carotene 15,15'-dioxygenase to such an extent that partial amino acid sequence information could be obtained to design degenerate oligonucleotides. With RT-PCR a cDNA fragment could be obtained and used subsequently in a radioactive screening of a chicken duodenal expression library. We cloned the first eukaryotic beta,beta-carotene 15,15'-dioxygenase which symmetrically cleaves beta-carotene at the 15,15'-double bond.


Assuntos
Oxigenases/genética , Oxigenases/metabolismo , Animais , Linhagem Celular , Galinhas , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Cricetinae , Citoplasma/enzimologia , DNA Complementar/metabolismo , Duodeno/enzimologia , Eletroforese em Gel de Poliacrilamida , Oxigenases/química , Peptídeos/química , Proteínas Recombinantes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , beta-Caroteno 15,15'-Mono-Oxigenase
18.
Am J Physiol ; 276(2): C395-403, 1999 02.
Artigo em Inglês | MEDLINE | ID: mdl-9950767

RESUMO

The calcium-binding protein parvalbumin (PV) occurs at high concentrations in fast-contracting vertebrate muscle fibers. Its putative role in facilitating the rapid relaxation of mammalian fast-twitch muscle fibers by acting as a temporary buffer for Ca2+ is still controversial. We generated knockout mice for PV (PV -/-) and compared the Ca2+ transients and the dynamics of contraction of their muscles with those from heterozygous (PV +/-) and wild-type (WT) mice. In the muscles of PV-deficient mice, the decay of intracellular Ca2+ concentration ([Ca2+]i) after 20-ms stimulation was slower compared with WT mice and led to a prolongation of the time required to attain peak twitch tension and to an extension of the half-relaxation time. The integral [Ca2+]i in muscle fibers of PV -/- mice was higher and consequently the force generated during a single twitch was approximately 40% greater than in PV +/- and WT animals. Acceleration of the contraction-relaxation cycle of fast-twitch muscle fibers by PV may confer an advantage in the performance of rapid, phasic movements.


Assuntos
Contração Muscular/fisiologia , Fibras Musculares de Contração Rápida/fisiologia , Músculo Esquelético/fisiologia , Parvalbuminas/fisiologia , Animais , Cálcio/fisiologia , Eletrofisiologia , Isomerismo , Camundongos , Camundongos Knockout/genética , Fibras Musculares de Contração Rápida/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Parvalbuminas/genética , Valores de Referência , Fatores de Tempo
19.
Trends Ecol Evol ; 13(11): 449-54, 1998 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-21238387

RESUMO

Recently discovered deposits containing terrestrial mammal fossils, together with multidisciplinary studies of classical sequences, have yielded dramatic insights into the biotic and environmental history of South America. Notable advances include several new fossil primate taxa, an improved chronology of two major immigration events (caviomorph rodents and new world monkeys), documentation of the oldest mammalian faunas dominated by grazing taxa (which suggests that grasslands appeared at least 15 million years earlier than on other continents), evidence of early biogeographical provinciality within South America, and improved sampling of the best known Cenozoic tropical South American paleofauna.

20.
Nature ; 385(6618): 712-4, 1997 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-9034186

RESUMO

Evidence of hair from several extinct mammals has been recovered from a rich accumulation of fossil excrement from the Late Palaeocene beds of Inner Mongolia, China. This highly unusual and previously undocumented depositional occurrence consists of hundreds of mammalian carnivore coprolites (fossil faeces) and a lesser number of probably raptorial bird regurgitalites (fossil pellets). The fossil hair occurs as impressions and natural casts in the extremely fine-grained, calcareous matrix that cements the skeletal remains within these faecal structures and preserves even the cuticular scale pattern on individual hair. Hair from at least four mammalian taxa, most notably the multituberculate Lambdopsalis bulla, has been identified. This record constitutes the first tangible evidence that, along with monotremes and therian mammals, multituberculates were hirsuite, and lends support for the presence of this mammalian feature in the most recent common ancestor of these three groups.


Assuntos
Fósseis , Cabelo , Mamíferos , Animais , Fezes
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