ABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
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.
Subject(s)
Delivery of Health Care/statistics & numerical data , Gastrointestinal Diseases/epidemiology , Meningitis/epidemiology , Patient Acceptance of Health Care/statistics & numerical data , Respiratory Tract Diseases/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Prevalence , Retrospective Studies , South Africa/epidemiology , Syndrome , Young AdultABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
Subject(s)
Typhoid Fever/epidemiology , Typhoid Fever/prevention & control , Typhoid-Paratyphoid Vaccines/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Epidemiologic Methods , Female , Geography , Humans , Male , Middle Aged , Random Allocation , Risk Assessment , Treatment Outcome , Typhoid-Paratyphoid Vaccines/administration & dosage , Young AdultABSTRACT
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.
Subject(s)
Bovine Virus Diarrhea-Mucosal Disease/epidemiology , Animals , Bovine Virus Diarrhea-Mucosal Disease/etiology , Brazil/epidemiology , Cattle , Diarrhea Viruses, Bovine Viral , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Insemination, Artificial/adverse effects , Insemination, Artificial/veterinary , Milk/virology , Prevalence , Risk FactorsABSTRACT
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.
Subject(s)
Aldehydes/chemistry , Drug Carriers/chemistry , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Polyethylene Glycols/chemistry , Adhesiveness , Administration, Oral , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Methacrylates/chemistryABSTRACT
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.
Subject(s)
Anti-Bacterial Agents/pharmacology , Disease Outbreaks/veterinary , Drug Resistance, Multiple, Bacterial , Poultry/microbiology , Salmonella Infections, Animal/microbiology , Salmonella Infections/microbiology , Salmonella enteritidis/isolation & purification , Animals , Bacteriophage Typing , Brazil/epidemiology , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Humans , Microbial Sensitivity Tests , Polymerase Chain Reaction/veterinary , Polymorphism, Restriction Fragment Length , Salmonella Infections/drug therapy , Salmonella Infections/epidemiology , Salmonella Infections, Animal/drug therapy , Salmonella Infections, Animal/epidemiology , Salmonella enteritidis/drug effects , Salmonella enteritidis/geneticsABSTRACT
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.
Subject(s)
Encephalitis, Japanese/epidemiology , Case-Control Studies , Child , Child, Preschool , Encephalitis, Japanese/prevention & control , Enzyme-Linked Immunosorbent Assay , Female , Humans , Indonesia/epidemiology , Infant , Infant, Newborn , Japanese Encephalitis Vaccines/therapeutic use , Logistic Models , Male , Risk FactorsABSTRACT
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.
Subject(s)
Cattle Diseases/parasitology , Hemostasis/drug effects , Immune Sera , Rhipicephalus/metabolism , Saliva/physiology , Tick Infestations/parasitology , Animals , Blood Coagulation/drug effects , Cattle , Cattle Diseases/immunology , Cell Line , Disease Models, Animal , Endothelial Cells , Hemostasis/physiology , Host-Parasite Interactions , Humans , Immune Sera/drug effects , Immune Sera/immunology , Immune Sera/pharmacology , Male , Neutralization Tests , Platelet Aggregation/drug effects , Rabbits , Rats , Rats, Wistar , Rhipicephalus/physiology , Saliva/immunology , Tick Infestations/immunology , Venous ThrombosisABSTRACT
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.
Subject(s)
Cattle Diseases/blood , Cattle Diseases/parasitology , Hemostasis/physiology , Rhipicephalus/growth & development , Tick Infestations/blood , Tick Infestations/veterinary , Animals , Cattle , Female , Fibrinogen/analysis , Partial Thromboplastin Time/veterinary , Platelet Aggregation/physiology , Platelet Count/veterinary , Prothrombin Time/veterinary , Tick Infestations/parasitologyABSTRACT
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.
Subject(s)
Antibodies, Protozoan/blood , Antigens, Protozoan/immunology , Immunoglobulin G/blood , Plasmodium falciparum/immunology , Recombinant Fusion Proteins/immunology , Adult , Amino Acid Sequence , Animals , Antigens, Protozoan/genetics , Antigens, Protozoan/metabolism , Cross-Sectional Studies , Escherichia coli/genetics , Ghana , Humans , Infant , Longitudinal Studies , Mice , Molecular Sequence Data , Phylogeny , Plasmodium falciparum/genetics , Sequence Alignment , Time FactorsABSTRACT
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.
Subject(s)
Antimalarials/therapeutic use , Chloroquine/therapeutic use , Malaria, Falciparum/drug therapy , Membrane Proteins/genetics , Plasmodium falciparum/genetics , Animals , Child , Child, Preschool , Drug Resistance/genetics , Female , Genotype , Ghana/epidemiology , Humans , Infant , Malaria, Falciparum/epidemiology , Male , Membrane Transport Proteins , Plasmodium falciparum/drug effects , Prospective Studies , Protozoan ProteinsSubject(s)
Colonic Neoplasms/prevention & control , Cyclooxygenase Inhibitors/therapeutic use , Epithelial Cells/pathology , Isoenzymes/genetics , Prostaglandin-Endoperoxide Synthases/genetics , Skin Neoplasms/prevention & control , Animals , Cyclooxygenase 2 , Cyclooxygenase 2 Inhibitors , Disease Models, Animal , Humans , Intestinal Mucosa/drug effects , Intestinal Mucosa/pathology , Membrane ProteinsABSTRACT
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.
Subject(s)
Cell Differentiation/physiology , Epidermis/pathology , Hair Follicle/physiology , Hair/abnormalities , Isoenzymes/metabolism , Prostaglandin-Endoperoxide Synthases/metabolism , Skin/enzymology , Skin/pathology , Aging , Animals , Cattle , Cell Division , Cyclooxygenase 2 , Epidermis/enzymology , Epidermis/growth & development , Hair/growth & development , Hair Follicle/cytology , Heterozygote , Hyperplasia , Isoenzymes/genetics , Keratins/genetics , Membrane Proteins/genetics , Mice , Mice, Transgenic , Phenotype , Promoter Regions, Genetic , Prostaglandin-Endoperoxide Synthases/genetics , Prostaglandins/metabolism , Protein Precursors/genetics , Reverse Transcriptase Polymerase Chain Reaction , Sebaceous Glands/pathology , Sebaceous Glands/physiopathology , Skin/growth & developmentABSTRACT
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.
Subject(s)
Chromosomes, Human, Pair 17/genetics , Epidermis/enzymology , Lipoxygenase/genetics , Multigene Family/genetics , Physical Chromosome Mapping , Amino Acid Sequence , Cloning, Molecular , Exons/genetics , Gene Expression , Humans , Introns/genetics , Isoenzymes/chemistry , Isoenzymes/genetics , Lipoxygenase/chemistry , Molecular Sequence Data , RNA, Messenger/analysis , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Sequence AlignmentSubject(s)
Alzheimer Disease/prevention & control , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Colorectal Neoplasms/prevention & control , Neoplasms/prevention & control , Alzheimer Disease/etiology , Animals , Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Colorectal Neoplasms/etiology , Cyclooxygenase 1 , Cyclooxygenase 2 , Humans , Isoenzymes/antagonists & inhibitors , Membrane Proteins , Neoplasms/etiology , Prostaglandin-Endoperoxide SynthasesABSTRACT
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.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Aspirin/adverse effects , Asthma/chemically induced , Cyclooxygenase Inhibitors/therapeutic use , Isoenzymes/antagonists & inhibitors , Sulfonamides/therapeutic use , Aged , Anaphylaxis/chemically induced , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Arthritis, Rheumatoid/drug therapy , Celecoxib , Cyclooxygenase 2 , Cyclooxygenase 2 Inhibitors , Female , Humans , Membrane Proteins , Prostaglandin-Endoperoxide Synthases , PyrazolesABSTRACT
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.
Subject(s)
Arachidonate 12-Lipoxygenase/metabolism , Epidermis/enzymology , Isoenzymes/metabolism , Animals , Cell Line , Chromatography, High Pressure Liquid , Humans , Mice , Spectrometry, Mass, Electrospray Ionization , Substrate SpecificityABSTRACT
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.