Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 268
Filtrar
1.
Sci Rep ; 10(1): 20181, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33188262

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

2.
S Afr Med J ; 109(5): 333-339, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31131801

RESUMO

BACKGROUND: Public health facilities are used by the majority of South Africans, and healthcare utilisation surveys have been a useful tool to estimate the burden of disease in a given area. OBJECTIVES: To describe care-seeking behaviour in a periurban site with a high prevalence of HIV infection, as well as barriers to seeking appropriate healthcare. METHODS: We conducted a cross-sectional household survey in 22 wards of the Msunduzi municipality in KwaZulu-Natal Province, South Africa, from October to December 2013 using a simple random sample of households selected from a 2011 census enumeration. A primary caregiver/adult decision-maker was interviewed regarding demographic data as well as health status and recent self-reported episodes of selected illnesses and healthcare utilisation. RESULTS: Of the 2 238 eligible premises visited, 1 936 households (87%) with a total of 9 733 members were enrolled in the study. Of these, 635 (7%) reported one or more episodes of infectious illness during the study period. Public health clinics were most frequently consulted for all illnesses (361/635, 57%). Private healthcare (general practitioner, private clinic, private hospital) was sought by 90/635 of individuals (14%), only 13/635 (2%) reported seeking care from traditional healers, religious leaders or volunteers, and 71/635 (11%) did not seek any medical care for acute illnesses. Individuals in the lowest income group were more likely to seek care at public health facilities than those in the highest income group (70% v. 32%). CONCLUSIONS: Public health facility-based surveillance may be representative of disease patterns in this community, although surveillance at household level shows that high-income individuals may be excluded because they were more likely to use private healthcare, and the proportion of individuals who died at home would have been missed by facility-based surveillance. Data obtained in such surveys may be useful for public health planning.


Assuntos
Atenção à Saúde/estatística & dados numéricos , Gastroenteropatias/epidemiologia , Meningite/epidemiologia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Doenças Respiratórias/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , África do Sul/epidemiologia , Síndrome , Adulto Jovem
3.
Sci Rep ; 9(1): 3382, 2019 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-30833683

RESUMO

We present a numerical investigation of the processes that influenced the contrasting rapid intensity changes in Tropical Cyclones (TC) Phailin and Lehar (2013) over the Bay of Bengal. Our emphasis is on the significant differences in the environments experienced by the TCs within a few weeks and the consequent differences in their organization of vortex-scale convection that resulted in their different rapid intensity changes. The storm-relative proximity, intensity, and depth of the subtropical ridge resulted in the establishment of a low-sheared environment for Phailin and a high-sheared environment for Lehar. Our primary finding here is that in Lehar's sheared vortex, the juxtaposition in the azimuthal phasing of the asymmetrically distributed downward eddy flux of moist-entropy through the top of the boundary layer, and the radial eddy flux of moist-entropy within the boundary layer in the upshear left-quadrant of Lehar (40-80 km radius) establishes a pathway for the low moist-entropy air to intrude into the vortex from the environment. Conversely, when the azimuthal variations in boundary layer moist-entropy, inflow, and convection are weak in Phailin's low-sheared environment, the inflow magnitude and radial location of boundary layer convergence relative to the radius of maximum wind dictated the rapid intensification.

4.
Q J R Meteorol Soc ; 144(Suppl Suppl 1): 16-26, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30774158

RESUMO

The Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission was selected by NASA as part of the Earth Venture-Instrument (EVI-3) program. The overarching goal for TROPICS is to provide nearly all-weather observations of 3D temperature and humidity, as well as cloud ice and precipitation horizontal structure, at high temporal resolution to conduct high-value science investigations of tropical cyclones. TROPICS will provide rapid-refresh microwave measurements (median refresh rate better than 60 min for the baseline mission) which can be used to observe the thermodynamics of the troposphere and precipitation structure for storm systems at the mesoscale and synoptic scale over the entire storm life cycle. TROPICS comprises six CubeSats in three low-Earth orbital planes. Each CubeSat will host a high-performance radiometer to provide temperature profiles using seven channels near the 118.75 GHz oxygen absorption line, water vapour profiles using three channels near the 183 GHz water vapour absorption line, imagery in a single channel near 90 GHz for precipitation measurements (when combined with higher-resolution water vapour channels), and a single channel near 205 GHz which is more sensitive to precipitation-sized ice particles. This observing system offers an unprecedented combination of horizontal and temporal resolution to measure environmental and inner-core conditions for tropical cyclones on a nearly global scale and is a major leap forward in the temporal resolution of several key parameters needed for assimilation into advanced data assimilation systems capable of utilizing rapid-update radiance or retrieval data. Launch readiness is currently projected for late 2019.

5.
Epidemiol Infect ; 143(16): 3520-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25936682

RESUMO

An individual's risk of infection from an infectious agent can depend on both the individual's own risk and protective factors and those of individuals in the same community. We hypothesize that an individual's exposure to an infectious agent is associated with the risks of infection of those living nearby, whether their risks are modified by pharmaceutical interventions or by other factors, because of the potential for transmission from them. For example, unvaccinated individuals living in a highly vaccinated community can benefit from indirect protection, or living near more children in a typhoid-endemic region (where children are at highest risk) might result in more exposure to typhoid. We tested this hypothesis using data from a cluster-randomized typhoid vaccine trial. We first estimated each individual's relative risk of confirmed typhoid outcome using their vaccination status and age. We defined a new covariate, potential exposure, to be the sum of the relative risks of all who live within 100 m of each person. We found that potential exposure was significantly associated with an individual's typhoid outcome, and adjusting for potential exposure affected estimates of vaccine efficacy. We suggest that it is useful and feasible to adjust for spatially heterogeneous distributions of individual-level risk factors, but further work is required to develop and test such approaches.


Assuntos
Febre Tifoide/epidemiologia , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Métodos Epidemiológicos , Feminino , Geografia , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória , Medição de Risco , Resultado do Tratamento , Vacinas Tíficas-Paratíficas/administração & dosagem , Adulto Jovem
6.
Res Vet Sci ; 95(3): 901-7, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24079841

RESUMO

A cross-sectional study was carried out to identify risk factors for bovine viral diarrhea virus (BVDV) infection in 300 randomly selected dairy herds which were tested for antibodies in bulk tank milk (BTM) using a commercial indirect ELISA kit (SVANOVA). Results from the analysis were interpreted according to the Swedish BVDV control scheme. The testing revealed 129 (43%) BTM BVDV antibody-positive herds. Use of artificial insemination (AI) and herd size were significantly associated with BVDV serological status (P<0.05). Dairy herds that use AI had 2.82 increased odds of BVDV-seropositivity (95% CI: 1.02-7.24). Since the semen used in the studied population come from known selected sires, it was hypothesized that AI technicians should represent an important risk factor because the increasing number of visitors in the farm can introduce the virus through the clothes, shoes and contaminated equipment.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/etiologia , Brasil/epidemiologia , Bovinos , Vírus da Diarreia Viral Bovina , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Inseminação Artificial/efeitos adversos , Inseminação Artificial/veterinária , Leite/virologia , Prevalência , Fatores de Risco
7.
J Biomater Sci Polym Ed ; 22(15): 2079-95, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21375804

RESUMO

Graft co-polymer networks have shown promise as devices for oral delivery of proteins. By increasing adhesion of these networks at the delivery site of the upper small intestine by utilizing small covalent chemical linkages caused by the addition of an aldehyde functional group we can make them more viable. These aldehydes bind covalently by way of a condensation reaction with the amines of the amino acids found in the glycoprotein network of the mucus layer of the small intestine to form imines. To investigate the effectiveness of this linkage the co-polymers are prepared in three different percentages of poly(ethylene glycol) (PEG) and aldehyde-modified PEG, and characterized through swelling, release and adhesion testing. The percentages of aldehyde-modified PEG used are 0.06, 0.6 and 3.3%. The swelling results indicate that the formulations with the aldehyde-modified PEG maintained the same pH sensitivity and transition around a pH of 5.8 as those formulations without the aldehyde moiety. Release results indicate that the release of insulin of the most promising 3.3% aldehyde formulation was successful with a release of about 80% after 3 h, which compares favorably with the similar release of the controls done in previous work. Adhesion testing was carried out through the use of a mechanical testing apparatus. Data have been gathered and plotted to give a detachment force (N) versus displacement (m) curve, of which the work of adhesion (µJ) was found by taking the area underneath the curve. Adhesion results indicate an increase to the already present adhesion of the co-polymers due to increased percentages of the aldehyde-modified PEG tethers where the 3.3% formulation showed an increase of 10-30 µJ over both control formulations.


Assuntos
Aldeídos/química , Portadores de Fármacos/química , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Polietilenoglicóis/química , Adesividade , Administração Oral , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Metacrilatos/química
8.
Poult Sci ; 89(7): 1530-6, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20548083

RESUMO

To investigate antimicrobial resistance, 96 Salmonella enterica subspecies enterica serovar Enteritidis strains isolated from salmonellosis outbreaks and poultry-related products obtained in southern Brazil were analyzed. Macrorestriction patterns, obtained by pulsed-field gel electrophoresis and phage types, were assessed. Although 43.75% of samples were sensitive to all drugs tested, resistance to sulfonamide (34.37%), trimethoprim-sulfamethoxazole (25.00%), nalidixic acid (14.58%), streptomycin (2.08%), gentamicin, and tetracycline (1.04%) was identified. Furthermore, 89.60% of strains belonged to phage type 4, and a predominant pulsed-field gel electrophoresis genotype represented by 82.29% of the strains was identified, suggesting that a clonal group was distributed in poultry, food, and human isolates. Although it was not possible to associate strains from different sources, the occurrence of antimicrobial-resistant Salmonella Enteritidis strains supports the need to establish monitoring programs to identify the emergence of potential resistance patterns and to direct policies for use of these drugs in food-producing animals.


Assuntos
Antibacterianos/farmacologia , Surtos de Doenças/veterinária , Farmacorresistência Bacteriana Múltipla , Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Infecções por Salmonella/microbiologia , Salmonella enteritidis/isolamento & purificação , Animais , Tipagem de Bacteriófagos , Brasil/epidemiologia , DNA Bacteriano/química , DNA Bacteriano/genética , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Fragmento de Restrição , Infecções por Salmonella/tratamento farmacológico , Infecções por Salmonella/epidemiologia , Salmonelose Animal/tratamento farmacológico , Salmonelose Animal/epidemiologia , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/genética
9.
Epidemiol Infect ; 138(9): 1292-7, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20109262

RESUMO

Japanese encephalitis (JE) has been found to be endemic in Bali, Indonesia. A case-control study was conducted to identify factors associated with JE infection. All 94 serologically confirmed JE cases (cases) and 163 cases of encephalitis or aseptic meningitis without JE (controls) identified in Bali during 2001-2004 were included in the study. Potential risk factors were surveyed at hospital admission. Univariate analyses revealed the following factors to be associated with JE: older age, referral from sub-district health centre or private hospital, playing outdoors after dinner, use of mosquito repellent or spraying, proximity of the residence to rice fields, and pig ownership by the family or next-door neighbours. Multivariate analysis identified proximity to rice fields (OR 2.93, 95% CI 1.57-5.45), pig ownership (OR 2.24, 95% CI 1.17-4.26), and older age (OR 1.21, 95% CI 1.09-1.33) as being independently associated with the risk of JE. Because rice cultivation and pig rearing are essential to the economy of Bali, JE immunization is the best intervention for prevention of JE in Bali.


Assuntos
Encefalite Japonesa/epidemiologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Encefalite Japonesa/prevenção & controle , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Indonésia/epidemiologia , Lactente , Recém-Nascido , Vacinas contra Encefalite Japonesa/uso terapêutico , Modelos Logísticos , Masculino , Fatores de Risco
10.
Parasitology ; 136(11): 1339-49, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19627637

RESUMO

Ticks are blood-feeding arthropods widely distributed in the world and vectors of several diseases. As haematophagy demands evasion strategies and repeatedly infested hosts develop protective immune responses, we investigated the mechanisms of the Rhipicephalus (Boophilus) microplus saliva anti-haemostatic activity and the possible relationship between the acquired natural anti-tick host resistance and anti-haemostatic action. For this purpose, we studied the effects of R. microplus saliva on different pathways of haemostasis and tested whether repeated infested bovine sera (RIBS) are able to abolish salivary anti-haemostatic activities. R. microplus saliva (i) displays inhibitory activity upon collagen-induced platelet aggregation; (ii) inhibits the induction of endothelial pro-coagulant state; and (iii) reduces thrombogenesis in vivo. RIBS were shown to be able to partially block the delay of coagulation and the anti-thrombotic effect of saliva, and to totally abolish the modulation of endothelium activation. Conversely, RIBS has no effect on the inhibition of platelet aggregation. These results show, for the first time, the neutralization ability of sera from acquired resistance hosts against tick anti-haemostatics. Moreover, this is the first report of a haematophagous parasite able to modulate endothelial cell pro-coagulant state, and addresses the presence of anti-platelet and anti-thrombotic activity in R. microplus saliva.


Assuntos
Doenças dos Bovinos/parasitologia , Hemostasia/efeitos dos fármacos , Soros Imunes , Rhipicephalus/metabolismo , Saliva/fisiologia , Infestações por Carrapato/parasitologia , Animais , Coagulação Sanguínea/efeitos dos fármacos , Bovinos , Doenças dos Bovinos/imunologia , Linhagem Celular , Modelos Animais de Doenças , Células Endoteliais , Hemostasia/fisiologia , Interações Hospedeiro-Parasita , Humanos , Soros Imunes/efeitos dos fármacos , Soros Imunes/imunologia , Soros Imunes/farmacologia , Masculino , Testes de Neutralização , Agregação Plaquetária/efeitos dos fármacos , Coelhos , Ratos , Ratos Wistar , Rhipicephalus/fisiologia , Saliva/imunologia , Infestações por Carrapato/imunologia , Trombose Venosa
11.
Res Vet Sci ; 86(1): 56-62, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18571684

RESUMO

The tick Rhipicephalus (Boophilus) microplus is a hematophagous ectoparasite that causes considerable economic losses to cattle breeding. Although R. microplus saliva contains several molecules that interfere with the blood coagulation process, so far the systemic alterations in the host hemostatic system have not been described. This study aims to determine if R. microplus infestation induces any disturbance to the host's hemostatic system. To address these questions, six calves were experimentally infested with 20,000 R. microplus larvae and their blood was collected before and 7, 14 and 21 days post-infestation. Collagen and ADP-induced platelet aggregation as well as coagulation (activated partial thromboplastin time and prothrombin time) decreased in infested bovines. Platelet blood count and fibrinogen increased during the course of infestation, probably as a compensatory response. These alterations may play a role in host health status, and show that the host cannot fully counteract the tick anti-hemostatic mechanisms.


Assuntos
Doenças dos Bovinos/sangue , Doenças dos Bovinos/parasitologia , Hemostasia/fisiologia , Rhipicephalus/crescimento & desenvolvimento , Infestações por Carrapato/sangue , Infestações por Carrapato/veterinária , Animais , Bovinos , Feminino , Fibrinogênio/análise , Tempo de Tromboplastina Parcial/veterinária , Agregação Plaquetária/fisiologia , Contagem de Plaquetas/veterinária , Tempo de Protrombina/veterinária , Infestações por Carrapato/parasitologia
12.
Parasitology ; 135(2): 155-67, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17931459

RESUMO

Clinical immunity to Plasmodium falciparum malaria develops after repeated exposure to the parasite. At least 2 P. falciparum variant antigens encoded by multicopy gene families (var and rif) are targets of this adaptive antibody-mediated immunity. A third multigene family of variant antigens comprises the stevor genes. Here, 4 different stevor sequences were selected for cloning and expression in Escherichia coli and His6-tagged fusion proteins were used for assessing the development of immunity. In a cross-sectional analysis of clinically immune adults living in a malaria endemic area in Ghana, high levels of anti-STEVOR IgG antibody titres were determined in ELISA. A cross-sectional study of 90 nine-month-old Ghanaian infants using 1 recombinant STEVOR showed that the antibody responses correlated positively with the number of parasitaemia episodes. In a longitudinal investigation of 17 immunologically naïve 9-month-old infants, 3 different patterns of anti-STEVOR antibody responses could be distinguished (high, transient and low). Children with high anti-STEVOR-antibody levels exhibited an elevated risk for developing parasitaemia episodes. Overall, a protective effect could not be attributed to antibodies against the STEVOR proteins chosen for the study presented here.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Imunoglobulina G/sangue , Plasmodium falciparum/imunologia , Proteínas Recombinantes de Fusão/imunologia , Adulto , Sequência de Aminoácidos , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/metabolismo , Estudos Transversais , Escherichia coli/genética , Gana , Humanos , Lactente , Estudos Longitudinais , Camundongos , Dados de Sequência Molecular , Filogenia , Plasmodium falciparum/genética , Alinhamento de Sequência , Fatores de Tempo
13.
QJM ; 98(11): 789-96, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16186171

RESUMO

BACKGROUND: Self-medication with anti-malarial drugs is widespread, and chloroquine (CQ) resistance is increasing. The effect of these factors on the incidence and presentation of severe malaria is uncertain. AIM: To investigate subtype of severe malaria, duration of illness, previous CQ treatment and prevalence of Plasmodium falciparum CQ-resistance markers among children presenting with severe malaria to a teaching hospital in Ghana. DESIGN: Prospective clinical study. METHODS: Consecutive patients (n = 189) presenting with severe malaria were examined clinically, and blood was taken for routine haematology and malaria films. Plasma and blood cells were stored and subsequently analysed by ELISA for CQ levels (n = 168) and by PCR and restriction digest for P. falciparum chloroquine resistance transporter gene (pfcrt) mutations (n = 139). RESULTS: Of 47 presenting with cerebral malaria, 21 had severe anaemia and 13 respiratory distress (RDS). Twenty-nine had prostration or RDS alone, 41 severe anaemia with prostration or RDS, and 72 severe anaemia not associated with coma, prostration or RDS. Of the patients studied, 77% had CQ in their plasma, and 88% were carrying P. falciparum with a CQ-resistance genotype. Significant associations were found (i) between the CQ-resistance genotype of parasites and plasma CQ levels, (ii) between the presence of CQ in plasma and the reported duration of illness, and (iii) between the reported duration of illness and the occurrence of severe but otherwise uncomplicated anaemia. DISCUSSION: There was extensive prior CQ use in our patients presenting with severe malaria, and a high prevalence of parasites with the CQ-resistance genotype. CQ resistance in P. falciparum may contribute to the development of severe but otherwise uncomplicated anaemia in this setting.


Assuntos
Antimaláricos/uso terapêutico , Cloroquina/uso terapêutico , Malária Falciparum/tratamento farmacológico , Proteínas de Membrana/genética , Plasmodium falciparum/genética , Animais , Criança , Pré-Escolar , Resistência a Medicamentos/genética , Feminino , Genótipo , Gana/epidemiologia , Humanos , Lactente , Malária Falciparum/epidemiologia , Masculino , Proteínas de Membrana Transportadoras , Plasmodium falciparum/efeitos dos fármacos , Estudos Prospectivos , Proteínas de Protozoários
15.
Proc Natl Acad Sci U S A ; 98(13): 7629-34, 2001 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-11381142

RESUMO

In prostanoid biosynthesis, the first two steps are catalyzed by cyclooxygenases (COX). In mice and humans, deregulated expression of COX-2, but not of COX-1, is characteristic of epithelial tumors, including squamous cell carcinomas of skin. To explore the function of COX-2 in epidermis, a keratin 5 promoter was used to direct COX-2 expression to the basal cells of interfollicular epidermis and the pilosebaceous appendage of transgenic mouse skin. COX-2 overexpression in the expected locations, resulting in increased prostaglandin levels in epidermis and plasma, correlated with a pronounced skin phenotype. Heterozygous transgenic mice exhibited a reduced hair follicle density. Moreover, postnatally hair follicle morphogenesis and thinning of interfollicular dorsal epidermis were delayed. Adult transgenics showed a body-site-dependent sparse coat of greasy hair, the latter caused by sebaceous gland hyperplasia and increased epicutaneous sebum levels. In tail skin, hyperplasia of scale epidermis reflecting an increased number of viable and cornified cell layers was observed. Hyperplasia was a result of a disturbed program of epidermal differentiation rather than an increased proliferation rate, as reflected by the strong suppression of keratin 10, involucrin, and loricrin expression in suprabasal cells. Further pathological signs were loss of cell polarity, mainly of basal keratinocytes, epidermal invaginations into the dermis, and formation of horn perls. Invaginating hyperplastic lobes were surrounded by CD31-positive vessels. These results demonstrate a causal relationship between transgenic COX-2 expression in basal keratinocytes and epidermal hyperplasia as well as dysplastic features at discrete body sites.


Assuntos
Diferenciação Celular/fisiologia , Epiderme/patologia , Folículo Piloso/fisiologia , Cabelo/anormalidades , Isoenzimas/metabolismo , Prostaglandina-Endoperóxido Sintases/metabolismo , Pele/enzimologia , Pele/patologia , Envelhecimento , Animais , Bovinos , Divisão Celular , Ciclo-Oxigenase 2 , Epiderme/enzimologia , Epiderme/crescimento & desenvolvimento , Cabelo/crescimento & desenvolvimento , Folículo Piloso/citologia , Heterozigoto , Hiperplasia , Isoenzimas/genética , Queratinas/genética , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Fenótipo , Regiões Promotoras Genéticas , Prostaglandina-Endoperóxido Sintases/genética , Prostaglandinas/metabolismo , Precursores de Proteínas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Glândulas Sebáceas/patologia , Glândulas Sebáceas/fisiopatologia , Pele/crescimento & desenvolvimento
16.
Genomics ; 73(3): 323-30, 2001 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-11350124

RESUMO

Epidermis-type lipoxygenases, a distinct subclass within the multigene family of mammalian lipoxygenases (LOX), comprise recently discovered novel isoenzymes isolated from human and mouse skin including human 15-LOX-2, human and mouse 12R-LOX, mouse 8S-LOX, and mouse e-LOX-3. We have isolated the human homologue of mouse e-LOX-3. The cDNA of 3362 bp encodes a 711-amino-acid protein displaying 89% sequence identity with the mouse protein and exhibiting the same unusual structural feature, i.e., an extra segment of 41 amino acids, which can be located beyond the N-terminal beta-barrel domain at the surface of the C-terminal catalytic domain. The gene encoding e-LOX-3, ALOXE3, was found to be part of a gene cluster of approximately 100 kb on human chromosome 17p13.1 containing in addition the 12R-LOX gene, ALOX12B, the 15-LOX-2 gene, ALOX15B, and a novel 15-LOX pseudogene, ALOX15P. ALOXE3 and ALOX12B are arranged in a head-to-tail fashion separated by 8.5 kb. The genes are split into 15 exons and 14 introns spanning 22 and 15 kb, respectively. ALOX15P was found on the opposite DNA strand directly adjacent to the 3'-untranslated region of ALOX12B. ALOX15B is located in the same orientation 25 kb downstream of ALOX12B, and is composed of 14 exons and 13 introns spanning a total of 9.7 kb of genomic sequence. RT-PCR analysis demonstrated a predominant expression of ALOXE3, ALOX12B, and ALOX15B in skin.


Assuntos
Cromossomos Humanos Par 17/genética , Epiderme/enzimologia , Lipoxigenase/genética , Família Multigênica/genética , Mapeamento Físico do Cromossomo , Sequência de Aminoácidos , Clonagem Molecular , Éxons/genética , Expressão Gênica , Humanos , Íntrons/genética , Isoenzimas/química , Isoenzimas/genética , Lipoxigenase/química , Dados de Sequência Molecular , RNA Mensageiro/análise , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência
18.
South Med J ; 94(2): 256-7, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11235048

RESUMO

We describe the case of an aspirin-sensitive asthma patient with a history of anaphylactic reactions to nonsteroidal anti-inflammatory drugs. The patient was subsequently diagnosed with rheumatoid arthritis and treated with a cyclooxygenase (COX)-2 inhibitor without an adverse response. Current prescribing information warns to avoid using COX-2 inhibitors in aspirin-sensitive asthma patients. New evidence suggests that aspirin sensitivity may be linked to the COX-1 pathway, and COX-2 inhibitors, as a result of their selectivity, may be beneficial in patients with aspirin-induced asthma.


Assuntos
Anti-Inflamatórios não Esteroides/efeitos adversos , Aspirina/efeitos adversos , Asma/induzido quimicamente , Inibidores de Ciclo-Oxigenase/uso terapêutico , Isoenzimas/antagonistas & inibidores , Sulfonamidas/uso terapêutico , Idoso , Anafilaxia/induzido quimicamente , Anti-Inflamatórios não Esteroides/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Celecoxib , Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase 2 , Feminino , Humanos , Proteínas de Membrana , Prostaglandina-Endoperóxido Sintases , Pirazóis
19.
Biochem J ; 355(Pt 1): 97-104, 2001 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-11256953

RESUMO

Substrate selectivity and other enzymic characteristics of two epidermis-derived lipoxygenases (LOXs), the epidermis-type (e) (12S)-LOX and (12R)-LOX, were compared with those of the platelet-type (p) (12S)-LOX. In contrast with p(12S)-LOX, e(12S)-LOX and (12R)-LOX exhibited no or very low reactivity towards the customary substrates linoleic acid and arachidonic acid but metabolized the corresponding fatty acid methyl esters, which, in contrast, were not accepted as substrates by p(12S)-LOX. Other esters of arachidonic acid and linoleic acid, including propan-2-yl and cholesterol esters, 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-linoleyl-sn-glycero-3-phosphoethanolamine, and ceramide 1 carrying an omega-linoleic acid ester, were not metabolized by these three LOX isoenzymes. Among various polyunsaturated fatty acids the isomeric eicosatrienoic acids were found to be oxygenated by e(12S)-LOX but not by (12R)-LOX. 4,7,10,13,16,19-Docosahexaenoic acid as a substrate was restricted to p(12S)-LOX. Variations in the pH and the Ca(2+) content of the incubation medium affected the catalytic potential only slightly. Whereas (12R)-LOX activity increased in the presence of Ca(2+) and with an acidic pH, Ca(2+) had no effect on p(12S)-LOX and e(12S)-LOX; an acidic pH decreased the catalytic activity of the latter two. However, the catalytic activity of the epidermis-type isoenzymes, but not of p(12S)-LOX, was found to be markedly increased in the presence of DMSO. Under these conditions, e(12S)-LOX and (12R)-LOX oxygenated 4,7,10,13,16,19-docosahexaenoic acid to 14-hydroxy-4,7,10,12,16,19-docosahexaenoic acid and 13-hydroxy-4,7,10,14,16,19-docosahexaenoic acid respectively. In addition, (9R)-hydroxyoctadeca-10,12-dienoic acid methyl ester was generated from linoleic acid methyl ester by (12R)-LOX. Independently of the substrate, the catalytic activity of e(12S)-LOX and (12R)-LOX was always at most 2% of that of p(12S)-LOX with arachidonic acid as substrate.


Assuntos
Araquidonato 12-Lipoxigenase/metabolismo , Epiderme/enzimologia , Isoenzimas/metabolismo , Animais , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Humanos , Camundongos , Espectrometria de Massas por Ionização por Electrospray , Especificidade por Substrato
20.
Gut ; 48(1): 80-6, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11115827

RESUMO

METHODS: Cellular localisation of the cyclooxygenase (COX) isozymes COX-1 and COX-2 was analysed in 24 cholangiocarcinomas, including 17 matched tissues originating from non-tumorous liver tissue adjacent to tumours and seven biopsies of normal human liver, by immunohistochemistry using isozyme selective antibodies. RESULTS: In normal liver, constitutive expression of COX-2 protein was a characteristic feature of hepatocytes whereas no COX-2 immunosignal was detectable in normal bile duct epithelium, Kupffer, and endothelial cells. In cholangiocarcinoma cells, COX-2 protein was strongly expressed at high frequency. The intensity, percentage of positive cells, and pattern of COX-2 expression were found to be independent of the stage of tumour differentiation. In hepatocytes of matched non-tumorous tissue, COX-2 expression was unaltered. In contrast, strong COX-1 expression was frequently localised to Kupffer cells, endothelial cells, and occasionally to hepatocytes, but not to bile duct epithelial cells. In approximately half of moderately and poorly differentiated but not well differentiated cholangiocarcinomas, weak to moderate COX-1 staining was found in tumour cells while COX-1 expression in Kupffer cells was much more pronounced. CONCLUSION: Aberrant COX-2 expression occurs during the early stage while COX-1 over expression seems to be related to later stages of cholangiocarcinogenesis.


Assuntos
Neoplasias dos Ductos Biliares/enzimologia , Ductos Biliares Intra-Hepáticos , Colangiocarcinoma/enzimologia , Isoenzimas/análise , Proteínas de Neoplasias/análise , Prostaglandina-Endoperóxido Sintases/análise , Adulto , Idoso , Neoplasias dos Ductos Biliares/patologia , Colangiocarcinoma/patologia , Ciclo-Oxigenase 1 , Ciclo-Oxigenase 2 , Feminino , Humanos , Imuno-Histoquímica , Células de Kupffer/enzimologia , Masculino , Proteínas de Membrana , Pessoa de Meia-Idade , Estatísticas não Paramétricas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...