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2.
Eur J Clin Microbiol Infect Dis ; 36(3): 537-544, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27885442

RESUMEN

We characterize the epidemiology of pediatric bloodstream infections (BSIs) in Switzerland. We analyzed pathogen distribution and resistance patterns in monomicrobial and polymicrobial BSIs in children from 2008 to 2014 using data from the Swiss antibiotic resistance centre (ANRESIS). A confirmatory statistical analysis was performed comparing pathogens and resistance across 20 acute care hospitals. We identified 3,067 bacteremia episodes, of which 1,823 (59 %) were considered true BSI episodes. Overall, S. aureus (16.5 %, 300) was the most frequent pathogen, followed by E. coli (15.1 %, 276), coagulase-negative staphylococci (CoNS, 12.9 %, 235), S. pneumoniae (11.1 %, 202) and non-E. coli Enterobacteriaceae (8.7 %, 159). S. aureus and E. coli showed similar frequencies in all of the variables analyzed (e.g., hospital acquisition, hospital type, medical specialty). The proportion of these microorganisms did not change over time, resistance rates remained low (4.3 % methicillin resistance in S. aureus; 7.3 % third-/fourth-generation cephalosporin resistance in E. coli), and no significant resistance trends were observed. We observed a 50 % increase of CoNS BSIs from 2008 (9.8 %, 27) to 2014 (15.2 %, 46, p value for trend = 0.03). S. pneumoniae decreased from 17.5 % (48) to 6.6 % (20) during that timeframe (p for trend = 0.007). S. aureus and E. coli remained the most significant pathogens among pediatric BSIs in Switzerland, exhibiting low resistance rates. CoNS accounted for a greater proportion of BSIs over time. The decrease in bacteremic pneumococcal infections can likely be attributed to the introduction of the 13-valent conjugate vaccine in 2011.


Asunto(s)
Bacterias/clasificación , Bacterias/aislamiento & purificación , Sepsis/epidemiología , Sepsis/patología , Adolescente , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Niño , Preescolar , Farmacorresistencia Bacteriana , Monitoreo Epidemiológico , Femenino , Humanos , Incidencia , Lactante , Recién Nacido , Masculino , Pruebas de Sensibilidad Microbiana , Sepsis/microbiología , Suiza/epidemiología
3.
Eur J Clin Microbiol Infect Dis ; 36(5): 839-846, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28025699

RESUMEN

This study evaluates whether estimated multidrug resistance (MDR) levels are dependent on the design of the surveillance system when using routine microbiological data. We used antimicrobial resistance data from the Antibiotic Resistance and Prescribing in European Children (ARPEC) project. The MDR status of bloodstream isolates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was defined using European Centre for Disease Prevention and Control (ECDC)-endorsed standardised algorithms (non-susceptible to at least one agent in three or more antibiotic classes). Assessment of MDR status was based on specified combinations of antibiotic classes reportable as part of routine surveillance activities. The agreement between MDR status and resistance to specific pathogen-antibiotic class combinations (PACCs) was assessed. Based on all available antibiotic susceptibility testing, the proportion of MDR isolates was 31% for E. coli, 30% for K. pneumoniae and 28% for P. aeruginosa isolates. These proportions fell to 9, 14 and 25%, respectively, when based only on classes collected by current ECDC surveillance methods. Resistance percentages for specific PACCs were lower compared with MDR percentages, except for P. aeruginosa. Accordingly, MDR detection based on these had low sensitivity for E. coli (2-41%) and K. pneumoniae (21-85%). Estimates of MDR percentages for Gram-negative bacteria are strongly influenced by the antibiotic classes reported. When a complete set of results requested by the algorithm is not available, inclusion of classes frequently tested as part of routine clinical care greatly improves the detection of MDR. Resistance to individual PACCs should not be considered reflective of MDR percentages in Enterobacteriaceae.


Asunto(s)
Bacteriemia/epidemiología , Farmacorresistencia Bacteriana Múltiple , Monitoreo Epidemiológico , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/epidemiología , Bacteriemia/microbiología , Europa (Continente)/epidemiología , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Prevalencia
4.
Antimicrob Agents Chemother ; 59(2): 782-9, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25403672

RESUMEN

The appropriate use of systemic antifungals is vital in the prevention and treatment of invasive fungal infection (IFI) in immunosuppressed children and neonates. This multicenter observational study describes the inpatient prescribing practice of antifungal drugs for children and neonates and identifies factors associated with prescribing variability. A single-day point prevalence study of antimicrobial use in hospitalized neonates and children was performed between October and December 2012. The data were entered through a study-specific Web-based portal using a standardized data entry protocol. Data were recorded from 17,693 patients from 226 centers. A total of 136 centers recorded data from 1,092 children and 380 neonates receiving at least one antifungal agent. The most frequently prescribed systemic antifungals were fluconazole (n=355) and amphotericin B deoxycholate (n=195). The most common indications for antifungal administration in children were medical prophylaxis (n=325), empirical treatment of febrile neutropenia (n=122), and treatment of confirmed or suspected IFI (n=100 [14%]). The treatment of suspected IFI in low-birthweight neonates accounted for the majority of prescriptions in the neonatal units (n=103). An analysis of variance (ANOVA) demonstrated no significant effect of clinical indication (prophylaxis or treatment of systemic or localized infection) on the total daily dose (TDD). Fewer than one-half of the patients (n=371) received a TDD within the dosing range recommended in the current guidelines. Subtherapeutic doses were prescribed in 416 cases (47%). The predominance of fluconazole and high incidence of subtherapeutic doses in participating hospitals may contribute to suboptimal clinical outcomes and an increased predominance of resistant pathogenic fungi. A global consensus on antifungal dosing and coordinated stewardship programs are needed to promote the consistent and appropriate use of antifungal drugs in neonates and children.


Asunto(s)
Anfotericina B/administración & dosificación , Antifúngicos/administración & dosificación , Ácido Desoxicólico/administración & dosificación , Adolescente , Anfotericina B/uso terapéutico , Antifúngicos/uso terapéutico , Niño , Preescolar , Ácido Desoxicólico/uso terapéutico , Combinación de Medicamentos , Fluconazol/administración & dosificación , Fluconazol/uso terapéutico , Hospitales , Humanos , Lactante , Recién Nacido
5.
Clin Microbiol Infect ; 26(7): 871-879, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31811919

RESUMEN

BACKGROUND: Amoxicillin has been in use since the 1970s; it is the most widely used penicillin both alone and in combination with the ß-lactamase clavulanic acid. OBJECTIVES: In this narrative review, we re-examine the properties of oral amoxicillin and clavulanic acid and provide guidance on their use, with emphasis on the preferred use of amoxicillin alone. SOURCES: Published medical literature (MEDLINE database via Pubmed). CONTENT: While amoxicillin and clavulanic acid have similar half-lives, clavulanic acid is more protein bound and even less heat stable than amoxicillin, with primarily hepatic metabolism. It is also more strongly associated with gastrointestinal side effects, including Clostridium difficile infection, and, thus, in oral combination formulations, limits the maximum daily dose of amoxicillin that can be given. The first ratio for an amoxicillin-clavulanic acid combination was set at 4:1 due to clavulanic acid's high affinity for ß-lactamases; ratios of 2:1, 7:1, 14:1 and 16:1 are currently available in various regions. Comparative effectiveness data for the different ratios are scarce. Amoxicillin-clavulanic acid is often used as empiric therapy for many of the World Health Organization's Priority Infectious Syndromes in adults and children, leading to extensive consumption, when some of these syndromes could be handled with a delayed antibiotic prescription approach or amoxicillin alone. IMPLICATIONS: Using available epidemiological and pharmacokinetic data, we provide guidance on indications for amoxicillin versus amoxicillin-clavulanic acid and on optimal oral administration, including choice of combination ratio. More data are needed, particularly on heat stability, pharmacodynamic effects and emergence of resistance in 'real-world' clinical settings.


Asunto(s)
Combinación Amoxicilina-Clavulanato de Potasio/administración & dosificación , Amoxicilina/administración & dosificación , Administración Oral , Amoxicilina/farmacocinética , Combinación Amoxicilina-Clavulanato de Potasio/farmacocinética , Cálculo de Dosificación de Drogas , Estabilidad de Medicamentos , Humanos , Guías de Práctica Clínica como Asunto
6.
Clin Microbiol Infect ; 26(1): 41-50, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31493472

RESUMEN

BACKGROUND: Antimicrobial stewardship interventions and programmes aim to ensure effective treatment while minimizing antimicrobial-associated harms including resistance. Practice in this vital area is undermined by the poor quality of research addressing both what specific antimicrobial use interventions are effective and how antimicrobial use improvement strategies can be implemented into practice. In 2016 we established a working party to identify the key design features that limit translation of existing research into practice and then to make recommendations for how future studies in this field should be optimally designed. The first part of this work has been published as a systematic review. Here we present the working group's final recommendations. METHODS: An international working group for design of antimicrobial stewardship intervention evaluations was convened in response to the fourth call for leading expert network proposals by the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR). The group comprised clinical and academic specialists in antimicrobial stewardship and clinical trial design from six European countries. Group members completed a structured questionnaire to establish the scope of work and key issues to develop ahead of a first face-to-face meeting that (a) identified the need for a comprehensive systematic review of study designs in the literature and (b) prioritized key areas where research design considerations restrict translation of findings into practice. The working group's initial outputs were reviewed by independent advisors and additional expertise was sought in specific clinical areas. At a second face-to-face meeting the working group developed a theoretical framework and specific recommendations to support optimal study design. These were finalized by the working group co-ordinators and agreed by all working group members. RESULTS: We propose a theoretical framework in which consideration of the intervention rationale the intervention setting, intervention features and the intervention aims inform selection and prioritization of outcome measures, whether the research sets out to determine superiority or non-inferiority of the intervention measured by its primary outcome(s), the most appropriate study design (e.g. experimental or quasi- experimental) and the detailed design features. We make 18 specific recommendation in three domains: outcomes, objectives and study design. CONCLUSIONS: Researchers, funders and practitioners will be able to draw on our recommendations to most efficiently evaluate antimicrobial stewardship interventions.


Asunto(s)
Programas de Optimización del Uso de los Antimicrobianos/organización & administración , Programas de Optimización del Uso de los Antimicrobianos/normas , Consenso , Antibacterianos/uso terapéutico , Bacterias/efectos de los fármacos , Ensayos Clínicos como Asunto , Europa (Continente) , Humanos , Internacionalidad , Proyectos de Investigación , Encuestas y Cuestionarios
8.
Clin Microbiol Infect ; 25(5): 555-561, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30472426

RESUMEN

BACKGROUND: Antimicrobial stewardship aims to optimize antibiotic use and minimize selection of antimicrobial resistance. The methodological quality of published studies in this field is unknown. AIMS: Our objective was to perform a comprehensive systematic review of antimicrobial stewardship research design and identify features which limit validity and translation of research findings into clinical practice. SOURCES: The following online database was searched: PubMed. STUDY ELIGIBILITY CRITERIA: Studies published between January 1950 and January 2017, evaluating any antimicrobial stewardship intervention in the community or hospital setting, without restriction on study design or outcome. CONTENT: We extracted data on pre-specified design quality features and factors that may influence design choices including (1) clinical setting, (2) age group studied, (3) when the study was conducted, (4) geographical region, and (5) financial support received. The initial search yielded 17 382 articles; 1008 were selected for full-text screening, of which 825 were included. Most studies (675/825, 82%) were non-experimental; 104 (15%) used interrupted time series analysis, 41 (6%) used external controls, and 19 (3%) used both. Studies in the community setting fulfilled a median of five out of 10 quality features (IQR 3-7) and 3 (IQR 2-4) in the hospital setting. Community setting studies (25%, 205/825) were significantly more likely to use randomization (OR 5.9; 95% CI 3.8-9.2), external controls (OR 5.6; 95% CI 3.6-8.5), and multiple centres (OR 10.5; 95% CI 7.1-15.7). From all studies, only 48% (398/825) reported clinical and 23% (190/825) reported microbiological outcomes. Quality did not improve over time. IMPLICATIONS: Overall quality of antimicrobial stewardship studies is low and has not improved over time. Most studies do not report clinical and microbiological outcome data. Studies conducted in the community setting were associated with better quality. These limitations should inform the design of future stewardship evaluations so that a robust evidence base can be built to guide clinical practice.


Asunto(s)
Antibacterianos/uso terapéutico , Programas de Optimización del Uso de los Antimicrobianos , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infección Hospitalaria/tratamiento farmacológico , Investigación sobre Servicios de Salud/métodos , Proyectos de Investigación/estadística & datos numéricos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Adulto Joven
9.
Clin Microbiol Infect ; 24(3): 251-257, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28830807

RESUMEN

OBJECTIVES: Neonates admitted to neonatal intensive care units (NICU) are at significant risk of developing bloodstream infections (BSIs). Gram-negative bacteria (GNB) both colonize and infect, but the association between these entities is unclear. By conducting a systematic literature review, we aimed to explore the impact of factors on the association between GN colonization and GN-BSI at both baby-level and unit-level. METHODS: We searched Medline, Embase, and Cochrane Library. Observational cohort studies published after 2000 up to June 2016 reporting data on the total number of neonates (0-28 days) colonized with GNB assessed by rectal/skin swab culture and the total number of neonates with GN-BSI (same bacteria) were included. Studies were excluded if data on skin/rectal colonization, neonates, and GNB could not be identified separately. Meta-analyses along with multivariate meta-regression with a random-effect model were performed to investigate factors associated with the GN colonization and GN-BSI at baby-level and unit-level. RESULTS: Twenty-seven studies fulfilled our inclusion criteria, 15 for the baby-level and 12 for the unit-level analysis. Study heterogeneity was high, with suboptimal overall quality of reporting assessed by the STROBE-NI statement (44.8% of items adequately reported). In 1984 colonized neonates, 157 (7.9%) developed GN-BSI compared with 85 of 3583 (2.4%) non-colonized neonates. Considerable heterogeneity was observed across studies. Four factors were included in the meta-regression model: gross domestic product (GDP), pathogen, outbreak, and frequency of screening. There was no statistically significant impact of these factors on GN colonization and GN-BSI in baby-level. We were unable to perform the multivariate meta-regression because of insufficient reported data for unit-level. CONCLUSIONS: Study limitations include the small number and the high heterogeneity of the included studies. While this report shows a correlation between colonization and BSI risk, these data currently do not support routine screening for GNB. Analysis of large cohorts of colonized neonates with clinical outcomes is still needed to define the major determinants leading from colonization to infection.


Asunto(s)
Bacteriemia/epidemiología , Portador Sano/epidemiología , Infecciones por Bacterias Gramnegativas/epidemiología , Estudios de Cohortes , Heces/microbiología , Bacterias Gramnegativas/aislamiento & purificación , Humanos , Recién Nacido , Recto/microbiología
10.
J Clin Invest ; 97(8): 1864-73, 1996 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-8621770

RESUMEN

We report studies that suggest enzyme replacement therapy will result in a significant reduction in disease progression and tissue pathology in patients with Maroteaux-Lamy syndrome (Mucopolysaccharidosis type VI, MPS VI). A feline model for MPS VI was used to evaluate tissue distribution and clinical efficacy of three forms of recombinant human N-acetylgalactosamine-4-sulfatase (rh4S, EC 3.1.6.1). Intravenously administered rh4S was rapidly cleared from circulation. The majority of rh4S was distributed to liver, but was also detected in most other tissues. Tissue half-life was approximately 2-4 d. Three MPS VI cats given regular intravenous infusions of rh4S for up to 20 mo showed variable reduction of storage vacuoles in Kupffer cells and connective tissues, however cartilage chondrocytes remained vacuolated. Vertebral bone mineral volume was improved in two MPS VI cats in which therapy was initiated before skeletal maturity, and increased bone volume appeared to correlate with earlier age of onset of therapy. One cat showed greater mobility in response to therapy.


Asunto(s)
Condro-4-Sulfatasa/uso terapéutico , Mucopolisacaridosis VI/terapia , Animales , Células CHO , Cartílago Articular/patología , Cartílago Articular/ultraestructura , Gatos , Condro-4-Sulfatasa/biosíntesis , Condro-4-Sulfatasa/farmacocinética , Cricetinae , Modelos Animales de Enfermedad , Glicosaminoglicanos/orina , Semivida , Humanos , Infusiones Intravenosas , Riñón/patología , Riñón/ultraestructura , Macrófagos del Hígado/patología , Macrófagos del Hígado/ultraestructura , Hígado/metabolismo , Hígado/patología , Lisosomas/ultraestructura , Tasa de Depuración Metabólica , Microscopía Electrónica , Mucopolisacaridosis VI/patología , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/uso terapéutico , Factores de Tiempo , Distribución Tisular , Transfección
11.
J Hosp Infect ; 94(2): 159-62, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27264244

RESUMEN

International infection prevention and control (IPC) guidelines provide standardized recommendations for healthcare-associated infection (HCAI) prevention in adults, but often lack specific information about neonates and children. We reviewed ten international IPC/HCAI guidelines to identify paediatric-specific recommendations for HCAI prevention. Hand hygiene, bloodstream infection, ventilator-associated pneumonia, environmental control and outbreak management were frequently reported with recommendations applicable to children and newborns, but documents on catheter-associated urinary tract infection and surgical site infection were lacking.


Asunto(s)
Infección Hospitalaria/prevención & control , Transmisión de Enfermedad Infecciosa/prevención & control , Control de Infecciones/métodos , Guías de Práctica Clínica como Asunto , Adolescente , Niño , Preescolar , Humanos , Lactante , Recién Nacido
12.
Arch Dis Child ; 101(1): 72-6, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26416900

RESUMEN

OBJECTIVE: To assess the availability and source of guidelines for common infections in European paediatric hospitals and determine their content and characteristics. DESIGN: Participating hospitals completed an online questionnaire on the availability and characteristics of antibiotic prescribing guidelines and on empirical antibiotic treatment including duration of therapy for 5 common infection syndromes: respiratory tract, urinary tract, skin and soft tissue, osteoarticular and sepsis in neonates and children. RESULTS: 84 hospitals from 19 European countries participated in the survey of which 74 confirmed the existence of guidelines. Complete guidelines (existing guidelines for all requested infection syndromes) were reported by 20% of hospitals and the majority (71%) used a range of different sources. Guidelines most commonly available were those for urinary tract infection (UTI) (74%), neonatal sepsis (71%) and sepsis in children (65%). Penicillin and amoxicillin were the antibiotics most commonly recommended for respiratory tract infections (RTIs) (up to 76%), cephalosporin for UTI (up to 50%) and for skin and soft tissue infection (SSTI) and bone infection (20% and 30%, respectively). Antistaphylococcal penicillins were recommended for SSTIs and bone infections in 43% and 36%, respectively. Recommendations for neonatal sepsis included 20 different antibiotic combinations. Duration of therapy guidelines was mostly available for RTI and UTI (82%). A third of hospitals with guidelines for sepsis provided recommendations for length of therapy. CONCLUSIONS: Comprehensive antibiotic guideline recommendations are generally lacking from European paediatric hospitals. We documented multiple antibiotics and combinations for most infections. Considerable improvement in the quality of guidelines and their evidence base is required, linking empirical therapy to resistance rates.


Asunto(s)
Antibacterianos/administración & dosificación , Hospitales Pediátricos/normas , Guías de Práctica Clínica como Asunto/normas , Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Niño , Preescolar , Estudios Transversales , Esquema de Medicación , Prescripciones de Medicamentos/normas , Prescripciones de Medicamentos/estadística & datos numéricos , Europa (Continente) , Humanos , Lactante , Recién Nacido , Pautas de la Práctica en Medicina/normas , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Sepsis/tratamiento farmacológico , Infecciones Urinarias/tratamiento farmacológico
13.
Clin Microbiol Infect ; 22(12): 1003.e1-1003.e8, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27585943

RESUMEN

Toxigenic Corynebacterium diphtheriae is an important and potentially fatal threat to patients and public health. During the current dramatic influx of refugees into Europe, our objective was to use whole genome sequencing for the characterization of a suspected outbreak of C. diphtheriae wound infections among refugees. After conventional culture, we identified C. diphtheriae using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and investigated toxigenicity by PCR. Whole genome sequencing was performed on a MiSeq Illumina with >70×coverage, 2×250 bp read length, and mapping against a reference genome. Twenty cases of cutaneous C. diphtheriae in refugees from East African countries and Syria identified between April and August 2015 were included. Patients presented with wound infections shortly after arrival in Switzerland and Germany. Toxin production was detected in 9/20 (45%) isolates. Whole genome sequencing-based typing revealed relatedness between isolates using neighbour-joining algorithms. We detected three separate clusters among epidemiologically related refugees. Although the isolates within a cluster showed strong relatedness, isolates differed by >50 nucleotide polymorphisms. Toxigenic C. diphtheriae associated wound infections are currently observed more frequently in Europe, due to refugees travelling under poor hygienic conditions. Close genetic relatedness of C. diphtheriae isolates from 20 refugees with wound infections indicates likely transmission between patients. However, the diversity within each cluster and phylogenetic time-tree analysis suggest that transmissions happened several months ago, most likely outside Europe. Whole genome sequencing offers the potential to describe outbreaks at very high resolution and is a helpful tool in infection tracking and identification of transmission routes.


Asunto(s)
Toxinas Bacterianas/genética , Corynebacterium diphtheriae/genética , Difteria/epidemiología , Brotes de Enfermedades , Infección de Heridas/epidemiología , Adolescente , Adulto , África/epidemiología , Toxinas Bacterianas/metabolismo , Técnicas de Tipificación Bacteriana , Corynebacterium diphtheriae/efectos de los fármacos , Corynebacterium diphtheriae/aislamiento & purificación , Difteria/tratamiento farmacológico , Farmacorresistencia Bacteriana Múltiple/genética , Femenino , Genes Bacterianos , Alemania/epidemiología , Humanos , Masculino , Familia de Multigenes , Tipificación de Secuencias Multilocus , Filogenia , Refugiados , Suiza/epidemiología , Siria/epidemiología , Infección de Heridas/tratamiento farmacológico , Infección de Heridas/microbiología , Adulto Joven
14.
Biochim Biophys Acta ; 1085(1): 7-14, 1991 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-1892880

RESUMEN

To address the hypothesis that phospholipid efflux from cells contributes to lipoprotein structure, we have examined the efflux of biosynthetically labeled [32P]phospholipid from cells to lipoproteins. With normal human skin fibroblasts in monolayer culture, high density lipoprotein (HDL3) promoted the efflux of phospholipid in a concentration-dependent manner. As analyzed by TLC, the major phospholipids released from fibroblasts were phosphatidylcholine, sphingomyelin, lysophosphatidylcholine and phosphatidylethanolamine. At identical concentrations, HDL3 and dimethylsuberimidate treated-HDL3 promoted similar efflux, suggesting that efflux did not depend on specific binding of HDL3 to the cell surface. When the content of cholesterol in fibroblasts was doubled by pre-incubation with LDL and cholesterol-rich liposomes, the fractional efflux of phospholipid to HDL3 and other acceptors was stimulated about 2-fold. Most of this stimulation was due to enhanced release of phosphatidylcholine. Similar effects of enrichment were found with Fu5AH rat hepatoma cells, but not with J774 mouse macrophages. The results support the hypothesis that the efflux of phospholipid from cells contributes to the phospholipid content of HDL. This may enhance the ability of HDL to remove cholesterol from cells, the initial step in reverse cholesterol transport.


Asunto(s)
HDL-Colesterol/metabolismo , Fibroblastos/metabolismo , Fosfolípidos/metabolismo , Animales , Transporte Biológico , Células Cultivadas , Cromatografía en Capa Delgada , Humanos , Liposomas , Macrófagos/metabolismo , Ratones , Ratas , Piel/metabolismo , Células Tumorales Cultivadas
15.
Biochim Biophys Acta ; 1258(1): 35-40, 1995 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-7654778

RESUMEN

Cigarette smoking is associated with an increased risk of premature atherosclerosis. The underlying mechanisms responsible for this association are unknown. Recent work from this laboratory has shown that ex vivo exposure to plasma to gas-phase cigarette smoke (CS) produces a rapid inhibition of lecithin-cholesterol acyltransferase (LCAT) activity and crosslinking of HDL-apolipoproteins. The goal of the present study was to investigate the mechanism(s) by which CS inhibited LCAT and modified HDL. When dialyzed human plasma (12 ml) was exposed to the gas-phase of an equivalent of 1/8 of a cigarette (one 'puff') at 15 min intervals for 3 h, LCAT activity was reduced by 76 +/- 1% compared to controls; supplementation of plasma with glutathione produced a dose-dependent protection of LCAT activity where at the highest concentration (1 mM) 78% protection was observed. A similar protection was obtained with N-acetyl cysteine (1 mM). In addition to LCAT inhibition, HDL-apolipoproteins were crosslinked after 3 h exposure of plasma to CS; crosslinking was reduced by the addition of either glutathione or N-acetyl cysteine to plasma. The amino compounds N-acetyl lysine, N-acetyl arginine, and aminoguanidine failed to protect LCAT and HDL indicating a specificity with regard to the ability of free thiols to buffer the deleterious components of CS which inhibited LCAT and crosslinked HDL-apolipoproteins. Since LCAT contains two free cysteine residues (Cys-31 and -184) near the active site of the enzyme, we tested whether pretreatment of plasma with the reversible sulfhydryl modifying compound, 5,5'-dithiobis-2-nitrobenzoic acid (DTNB), could protect LCAT from CS-induced inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Nicotiana , Fosfatidilcolina-Esterol O-Aciltransferasa/antagonistas & inhibidores , Fosfatidilcolina-Esterol O-Aciltransferasa/química , Plantas Tóxicas , Humo , Compuestos de Sulfhidrilo/química , Acetilcisteína/farmacología , Sitios de Unión , Reactivos de Enlaces Cruzados , Ácido Ditionitrobenzoico/farmacología , Glutatión/farmacología , Humanos , Lipoproteínas HDL/sangre , Fosfatidilcolina-Esterol O-Aciltransferasa/sangre , Fumar/efectos adversos
18.
Hum Gene Ther ; 3(4): 371-9, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1525210

RESUMEN

Three retroviral constructs containing a full-length human alpha-L-iduronidase (IDUA) cDNA were made. The first, pLIdSN, is designed so that expression of the IDUA cDNA is from the 5' viral long terminal repeat (LTR). The second, pLNCId, is designed to express the IDUA cDNA from the cytomegalovirus (CMV) immediate early promoter, while in the third, pLNTId, the CMV promoter is replaced by a promoter fragment of the mouse CD45 (T200) gene. All vectors transduce resistance to G418 (neomycin). High-titer virus-producing cell lines for these constructs were made by infection of the amphotropic packaging cell line PA317 after transient expression in, and virus rescue from, the ecotropic packaging cell line psi CRE. The high-titer virus-producing cell lines were assayed for absence of helper virus, synthesis of human IDUA, and for integrity of proviral structure. Suitable lines were used as a source of virus to infect two different mucopolysaccharidosis type I (MPS I) skin fibroblast cultures. All three of the recombinant viruses corrected the enzymatic defect in MPS I fibroblasts. Surprisingly, increasing over-expression of IDUA resulted in reduced phenotypic correction of these cells as assayed by intracellular accumulation of 35S-labeled glycosaminoglycan. This was shown to be due to the induction of a phenotype analogous to mild I-cell disease in cells expressing large amounts of IDUA.


Asunto(s)
Iduronidasa/genética , Mucopolisacaridosis/genética , Transfección , Células 3T3 , Animales , Fraccionamiento Celular , Línea Celular , Dermatán Sulfato/metabolismo , Fibroblastos/enzimología , Terapia Genética , Vectores Genéticos , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/metabolismo , Humanos , Iduronidasa/metabolismo , Lisosomas/enzimología , Ratones , Mucopolisacaridosis/enzimología , Mucopolisacaridosis/terapia , Retroviridae/genética
19.
Hum Gene Ther ; 7(16): 1965-70, 1996 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-8930656

RESUMEN

The recent cloning of the sulfamidase gene has made possible the consideration of gene-based therapies for Sanfilippo A syndrome (mucopolysaccharidosis type IIIA), one of the most common of the mucopolysaccharidoses. In this paper, we present the construction of a retroviral vector in which a sulfamidase cDNA is under the transcriptional control of the Moloney murine leukemia virus long terminal repeat. This construct was used to make a high-titer (4 x 10(5) colony-forming units/ml) producer cell line, PA317/LNSSN#19, in the amphotropic packaging cell line PA317. This producer cell line was shown to be helper virus free using an assay for horizontal spread of virus. Virus supernatant from PA317/LNSSN#19 was used to transduce Sanfilippo A fibroblasts, resulting in complete correction of both the enzymatic defect and the storage phenotype as assessed by intracellular accumulation of 35SO4(-)-labeled material. Phenotypic correction was seen even when the levels of viral transduction were low. These results show that gene therapy of the Sanfilippo A syndrome is practicable, although the nature of the disorder suggests that careful consideration needs to be given to the choice of the cellular target for gene transfer.


Asunto(s)
Fibroblastos/metabolismo , Transferencia de Gen Horizontal , Vectores Genéticos , Hidrolasas/genética , Virus de la Leucemia Murina de Moloney/genética , Células 3T3 , Animales , Línea Celular , Fibroblastos/citología , Glicosaminoglicanos/metabolismo , Ratones , Mucopolisacaridosis III/terapia , Piel/citología , Transfección
20.
Int J Biochem Cell Biol ; 31(3-4): 363-7, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10224661

RESUMEN

Sulphamidase is one of four lysosomal proteins whose deficiency clinically manifests as Sanfilippo syndrome. Deficiency of sulphamidase results in the lysosomal storage of the glycosaminoglycan (GAG) heparan sulphate (HS) and is termed mucopolysaccharidosis type IIIA (MPS IIIA). Sulphamidase catalyses the hydrolysis of an N-linked sulphate from the nonreducing terminal glucosaminide residue of HS (Fig. 1). It is unique among the known lysosomal sulphatases involved in GAG degradation in that it is an N-sulphatase, all the others being O-sulphatases. Purification of sulphamidase from human liver has facilitated the amino-terminal sequencing of the protein and hence the isolation of cDNA and genomic clones for sulphamidase. This has in turn made possible a range of further studies aimed at better diagnosis, treatment and understanding of MPS IIIA.


Asunto(s)
Hidrolasas/química , Humanos , Hidrolasas/biosíntesis , Hidrolasas/fisiología , Modelos Químicos , Modelos Genéticos
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