RESUMEN
BACKGROUND: No consensus on the management of symptomatic cysts or abscesses of the Bartholin's gland exists. OBJECTIVES: To assess the effectiveness and safety of surgical interventions for a symptomatic Bartholin's cyst or abscess. SEARCH STRATEGY: We searched bibliographical databases from inception to April 2019. SELECTION CRITERIA: Randomised trials evaluating a surgical intervention for the treatment of a symptomatic Bartholin's cyst or abscess. DATA COLLECTION AND ANALYSIS: Eight trials, reporting data from 699 women, were included. Study characteristics and methodological quality were recorded for each trial. Summary estimates were calculated using random-effects methods. MAIN RESULTS: When considering the recurrence of a symptomatic Bartholin's cyst or abscess, the evidence was consistent with notable effects in either direction (risk ratio [RR] 0.76; 95% confidence interval [CI] 0.41-1.40) when comparing marsupialisation with incision, drainage and insertion of a Word catheter. Limited inference could be made when comparing marsupialisation with incision, drainage and silver nitrate insertion (RR 1.00; 95% CI 0.57-1.75), and incision, drainage and cavity closure (RR 0.25; 95% CI 0.01-4.89). There was limited reporting of secondary outcomes, including haematoma, infectious morbidity and persistent dyspareunia. CONCLUSIONS: Current randomised trial evidence does not support the use of any single surgical intervention for the treatment of a symptomatic cyst or abscess of the Bartholin's gland. PROSPECTIVE REGISTRATION: PROSPERO: International Prospective Register of Systematic Reviews; CRD42018088553. TWEETABLE ABSTRACT: Further research is needed to identify an effective treatment for #Bartholin's cyst or abscess. @jamesmnduffy.
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Absceso/cirugía , Glándulas Vestibulares Mayores/patología , Quistes/cirugía , Procedimientos Quirúrgicos Ginecológicos/métodos , Enfermedades de la Vulva/patología , Técnicas de Ablación , Glándulas Vestibulares Mayores/cirugía , Drenaje , Femenino , Humanos , Evaluación de Necesidades , Ensayos Clínicos Controlados Aleatorios como Asunto , Enfermedades de la Vulva/clasificación , Enfermedades de la Vulva/cirugíaRESUMEN
STUDY QUESTION: How much statistical power do randomised controlled trials (RCTs) and meta-analyses have to investigate the effectiveness of interventions in reproductive medicine? SUMMARY ANSWER: The largest trials in reproductive medicine are unlikely to detect plausible improvements in live birth rate (LBR), and meta-analyses do not make up for this shortcoming. WHAT IS KNOWN ALREADY: Effectiveness of interventions is best evaluated using RCTs. In order to be informative, these trials should be designed to have sufficient power to detect the smallest clinically relevant effect. Similar trials can subsequently be pooled in meta-analyses to more precisely estimate treatment effects. STUDY DESIGN, SIZE, DURATION: A review of power and precision in 199 RCTs and meta-analyses from 107 Cochrane Reviews was conducted. PARTICIPANTS/MATERIALS, SETTING, METHODS: Systematic reviews published by Cochrane Gynaecology and Fertility with the primary outcome live birth were identified. For each live birth (or ongoing pregnancy) meta-analysis and for the largest RCT in each, we calculated the power to detect absolute improvements in LBR of varying sizes. Additionally, the 95% CIs of estimated treatment effects from each meta-analysis and RCT were recorded, as these indicate the precision of the result. MAIN RESULTS AND THE ROLE OF CHANCE: Median (interquartile range) power to detect an improvement in LBR of 5 percentage points (pp) (e.g. 25-30%) was 13% (8-21%) for RCTs and 16% (9-33%) for meta-analyses. No RCTs and only 2% of meta-analyses achieved 80% power to detect an improvement of 5 pp. Median power was high (85% for trials and 93% for meta-analyses) only in relation to 20 pp absolute LBR improvement, although substantial numbers of trials and meta-analyses did not achieve 80% power even for this improbably large effect size. Median width of 95% CIs was 25 pp and 21 pp for RCTs and meta-analyses, respectively. We found that 28% of Cochrane Reviews with LBR as the primary outcome contain no live birth (or ongoing pregnancy) data. LARGE-SCALE DATA: The data used in this study may be accessed at https://osf.io/852tn/?view_only=90f1579ce72747ccbe572992573197bd. LIMITATIONS, REASONS FOR CAUTION: The design and analysis decisions used in this study are predicted to overestimate the power of trials and meta-analyses, and the size of the problem is therefore likely understated. For some interventions, it is possible that larger trials not reporting live birth or ongoing pregnancy have been conducted, which were not included in our sample. In relation to meta-analyses, we calculated power as though all participants were included in a single trial. This ignores heterogeneity between trials in a meta-analysis, and will cause us to overestimate power. WIDER IMPLICATIONS OF THE FINDINGS: Trials capable of detecting realistic improvements in LBR are lacking in reproductive medicine, and meta-analyses are not large enough to overcome this deficiency. This situation will lead to unwarranted pessimism as well as unjustified enthusiasm regarding reproductive interventions, neither of which are consistent with the practice of evidence-based medicine or the idea of informed patient choice. However, RCTs and meta-analyses remain vital to establish the effectiveness of fertility interventions. We discuss strategies to improve the evidence base and call for collaborative studies focusing on the most important research questions. STUDY FUNDING/COMPETING INTEREST(S): There was no specific funding for this study. KS and SL declare no conflict of interest. AV consults for the Human Fertilisation and Embryology Authority (HFEA): all fees are paid directly to AV's employer. JW declares that publishing research benefits his career. SR is a Statistical Editor for Human Reproduction. JW and AV are Statistical Editors for Cochrane Gynaecology and Fertility. DRB is funded by the NHS as Scientific Director of a clinical IVF service. PROSPERO REGISTRATION NUMBER: None.
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Tasa de Natalidad/tendencias , Infertilidad/terapia , Nacimiento Vivo , Medicina Reproductiva/métodos , Femenino , Humanos , Embarazo , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del TratamientoRESUMEN
BACKGROUND: Noninvasive quantitative assessment of dermal fibrosis remains a challenge. Optical coherence tomography (OCT) and high-frequency ultrasound (HFUS) can accurately measure structural and physiological changes in skin. OBJECTIVES: To perform quantitative analysis of cutaneous fibrosis. METHODS: Sixty-two healthy volunteers underwent multiple sequential skin biopsies (day 0 and 1-8 weekly thereafter), with OCT and HFUS measurements at each time point supported with immunohistomorphometry analysis. RESULTS: HFUS and OCT provided quantitative measurements of skin thickness, which increased from uninjured skin (1·18 and 1·2 mm, respectively) to week 1 (1·28 mm, P = 0·01; 1·27 mm, P = 0·02), and compared favourably with haematoxylin and eosin. Spearman correlation showed good agreement between techniques (P < 0·001). HFUS intensity corresponded to dermal density, with reduction from uninjured skin (42%) to week 8 (29%) (P = 0·02). The OCT attenuation coefficient linked with collagen density and was reduced at week 8 (1·43 mm, P < 0·001). Herovici analysis showed that mature collagen levels were highest in uninjured skin (72%) compared with week 8 (42%, P = 0·04). Fibronectin was greatest at week 4 (0·72 AU) and reduced at week 8 (0·56 AU); and α-smooth muscle actin increased from uninjured skin (11·5%) to week 8 (67%, P = 0·003). CONCLUSIONS: Time-matched comparison images between haematoxylin and eosin, OCT and HFUS demonstrated that epidermal and dermal structures were better distinguished by OCT. HFUS enabled deeper visualization of the dermis including the subcutaneous tissue. Choice of device was dependent on the depth of scar type, parameters to be measured and morphological detail required in order to provide better objective quantitative indices of the quality and extent of dermal fibrosis.
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Cicatriz/diagnóstico por imagen , Dermis/patología , Adulto , Biopsia/efectos adversos , Cicatriz/etiología , Cicatriz/patología , Dermis/diagnóstico por imagen , Femenino , Fibrosis , Voluntarios Sanos , Humanos , Inmunohistoquímica , Masculino , Tomografía de Coherencia Óptica , Ultrasonografía , Adulto JovenRESUMEN
Bacterial pneumonia is an increasing complication of HIV infection and inversely correlates with the CD4(+) lymphocyte count. Interleukin (IL)-17 is a cytokine produced principally by CD4(+) T cells, which induces granulopoiesis via granulocyte colony-stimulating factor (G-CSF) production and induces CXC chemokines. We hypothesized that IL-17 receptor (IL-17R) signaling is critical for G-CSF and CXC chemokine production and lung host defenses. To test this, we used a model of Klebsiella pneumoniae lung infection in mice genetically deficient in IL-17R or in mice overexpressing a soluble IL-17R. IL-17R-deficient mice were exquisitely sensitive to intranasal K. pneumoniae with 100% mortality after 48 h compared with only 40% mortality in controls. IL-17R knockout (KO) mice displayed a significant delay in neutrophil recruitment into the alveolar space, and had greater dissemination of K. pneumoniae compared with control mice. This defect was associated with a significant reduction in steady-state levels of G-CSF and macrophage inflammatory protein (MIP)-2 mRNA and protein in the lung in response to the K. pneumoniae challenge in IL-17R KO mice. Thus, IL-17R signaling is critical for optimal production of G-CSF and MIP-2 and local control of pulmonary K. pneumoniae infection. These data support impaired IL-17R signaling as a potential mechanism by which deficiency of CD4 lymphocytes predisposes to bacterial pneumonia.
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Quimiocinas CXC/metabolismo , Factor Estimulante de Colonias de Granulocitos/metabolismo , Pulmón/metabolismo , Neutrófilos/citología , Receptores de Interleucina/metabolismo , Proteínas Recombinantes/metabolismo , Transducción de Señal , Animales , Líquido del Lavado Bronquioalveolar , Infecciones por Klebsiella/inmunología , Klebsiella pneumoniae/aislamiento & purificación , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Interleucina/genética , Receptores de Interleucina-17 , Proteínas Recombinantes/genéticaRESUMEN
C57BL/6 mice genetically deficient in interleukin 15 (IL-15(-/-) mice) were generated by gene targeting. IL-15(-/-) mice displayed marked reductions in numbers of thymic and peripheral natural killer (NK) T cells, memory phenotype CD8(+) T cells, and distinct subpopulations of intestinal intraepithelial lymphocytes (IELs). The reduction but not absence of these populations in IL-15(-/-) mice likely reflects an important role for IL-15 for expansion and/or survival of these cells. IL-15(-/-) mice lacked NK cells, as assessed by both immunophenotyping and functional criteria, indicating an obligate role for IL-15 in the development and functional maturation of NK cells. Specific defects associated with IL-15 deficiency were reversed by in vivo administration of exogenous IL-15. Despite their immunological defects, IL-15(-/-) mice remained healthy when maintained under specific pathogen-free conditions. However, IL-15(-/-) mice are likely to have compromised host defense responses to various pathogens, as they were unable to mount a protective response to challenge with vaccinia virus. These data reveal critical roles for IL-15 in the development of specific lymphoid lineages. Moreover, the ability to rescue lymphoid defects in IL-15(-/-) mice by IL-15 administration represents a powerful means by which to further elucidate the biological roles of this cytokine.
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Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Interleucina-15/inmunología , Células Asesinas Naturales/inmunología , Receptores de Interleucina-2/inmunología , Animales , Linaje de la Célula , Células Epiteliales/inmunología , Femenino , Interleucina-15/genética , Ganglios Linfáticos/anatomía & histología , Ganglios Linfáticos/inmunología , Recuento de Linfocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Tamaño de los Órganos , Receptores de Interleucina-15 , Receptores de Interleucina-2/genética , Bazo/anatomía & histología , Bazo/inmunología , Timo/anatomía & histología , Timo/inmunología , Vaccinia/mortalidadRESUMEN
The ectodomains of numerous proteins are released from cells by proteolysis to yield soluble intercellular regulators. The responsible protease, tumor necrosis factor-alpha converting enzyme (TACE), has been identified only in the case when tumor necrosis factor-alpha (TNFalpha) is released. Analyses of cells lacking this metalloproteinase-disintegrin revealed an expanded role for TACE in the processing of other cell surface proteins, including a TNF receptor, the L-selectin adhesion molecule, and transforming growth factor-alpha (TGFalpha). The phenotype of mice lacking TACE suggests an essential role for soluble TGFalpha in normal development and emphasizes the importance of protein ectodomain shedding in vivo.
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Membrana Celular/metabolismo , Desarrollo Embrionario y Fetal , Proteínas de la Membrana/metabolismo , Metaloendopeptidasas/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Proteínas ADAM , Proteína ADAM17 , Secuencia de Aminoácidos , Animales , Dominio Catalítico , Células Cultivadas , Cruzamientos Genéticos , Selectina L/metabolismo , Ligandos , Metaloendopeptidasas/química , Metaloendopeptidasas/genética , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Mutación , Fenotipo , Procesamiento Proteico-Postraduccional , Receptores del Factor de Necrosis Tumoral/metabolismo , Factor de Crecimiento Transformador alfa/metabolismoRESUMEN
Both the murine and human genomic loci that encode flt3 ligand have been cloned. flt3 ligand is a hematopoietic growth factor that stimulates the proliferation of stem and progenitor cells. The portions of the murine and human flt3 ligand genomic loci encompassing the coding region of the protein are approximately 4.0 kb and 5.9 kb, respectively. The human genomic locus is larger as a result of the presence of repeated sequences within introns I, II, IV, V and VI. The transmembrane isoform of the murine and human flt3 ligand proteins are each encoded within seven exons (1-5 + 7 and 8). Analyses of flt3 ligand cDNA clones show that alternative splicing of a putative sixth exon results in the generation of a soluble form of the flt3 ligand protein. The sizes of each of the exons are well conserved between species. Murine and human flt3 genomic loci have a similar exon: intron structure compared to the genomic loci encoding Steel factor and colony stimulating factor 1. These proteins, which appear to be ancestrally related, are hematopoietic growth factors that stimulate cells via specific and structurally related tyrosine kinase receptors on the cell surface.
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Mapeo Cromosómico , Factores de Crecimiento de Célula Hematopoyética/genética , Proteínas de la Membrana/genética , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Médula Ósea/metabolismo , Exones , Humanos , Factor Estimulante de Colonias de Macrófagos/genética , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Bazo/metabolismo , Factor de Células Madre/genéticaRESUMEN
We have recently described a novel hematopoietic growth factor, referred to as the flt3 ligand, that stimulates the proliferation of sub-populations of hematopoietic cells that are enriched for stem and progenitor cells. This factor is a transmembrane protein that undergoes proteolytic cleavage to generate a soluble form of the protein. We have isolated additional flt3 ligand isoforms by PCR that contain an extra exon and encode what are predicted to be either a soluble form of the ligand or a longer version of the transmembrane protein. We have also isolated cDNAs from murine T cell libraries that encode an isoform of the flt3 ligand that has an unusual C-terminus. This isoform results from a failure to splice out an intron during mRNA processing. The protein encoded by this cDNA is expressed on the cell surface, where it is biologically active. However, this novel isoform does not appear to give rise to a soluble form of the protein. Regulation of mRNA splicing is likely to control the generation of cell bound or soluble forms of this hematopoietic growth factor. Genetic mapping studies localize the gene encoding the flt3 ligand to the proximal portion of mouse chromosome 7 and to human chromosome 19q13.3.
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Empalme Alternativo , Sustancias de Crecimiento/análisis , Proteínas de la Membrana/análisis , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Humanos Par 19 , ADN Complementario , Femenino , Sustancias de Crecimiento/genética , Humanos , Intrones , Masculino , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , ARN Mensajero/genética , SolubilidadRESUMEN
Cardiovascular responses to strength conditioning exercises were examined in 12 healthy pregnant women and their unborn fetuses during the third trimester. A group of 12 healthy nonpregnant women of similar ages, parity, body height, and pre-pregnant body mass was also studied. Maternal heart rate and blood pressure and fetal heart rate (FHR) responses were measured in both the supine (30 degrees tilt) and seated postures during handgrip (HG), single-leg extension (SL), and double-leg extension (DL) exercise. Subjects performed 3 sets of 10 reps at 50, 70, and 90% of their 10-repetition maximum (10-RM) for each exercise in both postures. Pregnant subjects exhibited higher heart rates but similar blood pressure responses to control subjects under all experimental conditions. Significant increases were observed for the frequency of FHR accelerations (0.10 to 0.27/min) from rest to DL in the sitting posture at 90% RM. Moderate fetal bradycardia was observed occasionally in the tilted supine posture at rest and both during (SL, DL) and following (HG, SL, DL) exercise, suggesting that this posture should be avoided in late gestation. The results support the safety of moderate strength conditioning exercises in healthy pregnancy.
Asunto(s)
Ejercicio Físico/fisiología , Frecuencia Cardíaca Fetal/fisiología , Embarazo/fisiología , Adulto , Análisis de Varianza , Presión Sanguínea/fisiología , Prueba de Esfuerzo , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Resistencia Física/fisiología , Postura , Resultado del Embarazo , Tercer Trimestre del EmbarazoRESUMEN
IL-1 alpha and IL-1 beta bind to receptors termed the type I and type II IL-1 receptors. The type I IL-1 receptor is responsible for specific signaling, while the type II IL-1 receptor functions as a nonsignaling decoy receptor. To determine the effect of a defect in IL-1-mediated signaling, mice have been produced with a genetically disrupted type I IL-1 receptor gene. Mice lacking type I IL-1 receptors are of normal vigor and exhibit no overt phenotype. B cells from type I IL-1R-/- mice activated in vitro with anti-IgM do not proliferate in response to IL-1, but do so in response to IL-4. Injection of murine IL-1 alpha does not induce detectable serum IL-6 levels in type I IL-1R-/- mice, but equivalent levels are produced in response to LPS. Type I IL-1R-/- mice have normal serum Ig levels and generate equivalent primary and secondary Ab responses as wild-type mice. In response to LPS, acute phase protein mRNA induction are equivalent in type I IL-1R-/- and wild-type mice. Type I IL-1R-/- mice do not differ from control mice in susceptibility to either a lethal challenge with D-galactosamine plus LPS or high dose LPS. Interestingly, ICE-/-/type I IL-1R-/- double mutant mice are resistant to high dose LPS. Type I IL-1R-/- mice backcrossed to the C57BL/6 background were as equally resistant as wild-type mice to Listeria monocytogenes.
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Ratones Noqueados/genética , Ratones Noqueados/inmunología , Receptores de Interleucina-1/deficiencia , Receptores de Interleucina-1/genética , Proteínas de Fase Aguda/biosíntesis , Animales , Caspasa 1 , Cisteína Endopeptidasas/deficiencia , Cisteína Endopeptidasas/genética , Susceptibilidad a Enfermedades , Femenino , Inmunidad Innata , Interleucina-1/farmacología , Interleucina-6/biosíntesis , Interleucina-6/sangre , Lipopolisacáridos/toxicidad , Listeriosis/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Fenotipo , Receptores de Interleucina-1/fisiologíaRESUMEN
4-1BB ligand (4-1BBL) is a member of the TNF family expressed on activated APC. 4-1BBL binds to 4-1BB (CD137) on activated CD4 and CD8 T cells and in conjunction with strong signals through the TCR provides a CD28-independent costimulatory signal leading to high level IL-2 production by primary resting T cells. Here we report the immunological characterization of mice lacking 4-1BBL and of mice lacking both 4-1BBL and CD28. 4-1BBL-/- mice mount neutralizing IgM and IgG responses to vesicular stomatitis virus that are indistinguishable from those of wild-type mice. 4-1BBL-/- mice show unimpaired CTL responses to lymphocytic choriomeningitis virus (LCMV) and exhibit normal skin allograft rejection but have a weaker CTL response to influenza virus than wild-type mice. 4-1BBL-/-CD28-/- mice retain the CTL response to LCMV, respond poorly to influenza virus, and exhibit a delay in skin allograft rejection. In agreement with these in vivo results, allogeneic CTL responses of CD28-/- but not CD28+/+ T cells to 4-1BBL-expressing APC are substantially inhibited by soluble 4-1BB receptor as is the in vitro secondary response of CD28+ T cells to influenza virus peptides. TCR-transgenic CD28-/- LCMV glycoprotein-specific T cells are insensitive to the presence of 4-1BBL when a wild-type peptide is used, but the response to a weak agonist peptide is greatly augmented by the presence of 4-1BBL. These results further substantiate the idea that different immune responses vary in their dependence on costimulation and suggest a role for 4-1BBL in augmenting suboptimal CTL responses in vivo.
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Antígenos CD28/genética , Citotoxicidad Inmunológica/genética , Rechazo de Injerto/inmunología , Virus de la Influenza A/inmunología , Trasplante de Piel/inmunología , Linfocitos T Citotóxicos/inmunología , Factor de Necrosis Tumoral alfa/deficiencia , Factor de Necrosis Tumoral alfa/genética , Ligando 4-1BB , Animales , Anticuerpos Antivirales/biosíntesis , Antígenos CD28/fisiología , Femenino , Marcación de Gen , Rechazo de Injerto/genética , Ligandos , Virus de la Coriomeningitis Linfocítica/inmunología , Masculino , Ratones , Ratones Endogámicos A , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Linfocitos T Citotóxicos/virología , Células Tumorales Cultivadas , Factor de Necrosis Tumoral alfa/fisiología , Virus de la Estomatitis Vesicular Indiana/inmunologíaRESUMEN
The amyloid protein, Abeta, which accumulates in the brains of Alzheimer patients, is derived by proteolysis of the amyloid protein precursor (APP). APP can undergo endoproteolytic processing at three sites, one at the amino terminus of the Abeta domain (beta-cleavage), one within the Abeta domain (alpha-cleavage), and one at the carboxyl terminus of the Abeta domain (gamma-cleavage). The enzymes responsible for these activities have not been unambiguously identified. By the use of gene disruption (knockout), we now demonstrate that TACE (tumor necrosis factor alpha converting enzyme), a member of the ADAM family (a disintegrin and metalloprotease-family) of proteases, plays a central role in regulated alpha-cleavage of APP. Our data suggest that TACE may be the alpha-secretase responsible for the majority of regulated alpha-cleavage in cultured cells. Furthermore, we show that inhibiting this enzyme affects both APP secretion and Abeta formation in cultured cells.
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Precursor de Proteína beta-Amiloide/metabolismo , Endopeptidasas/metabolismo , Metaloendopeptidasas/metabolismo , Proteínas ADAM , Proteína ADAM17 , Secretasas de la Proteína Precursora del Amiloide , Animales , Ácido Aspártico Endopeptidasas , Células Cultivadas , Embrión de Mamíferos/citología , Fibroblastos , Metaloendopeptidasas/antagonistas & inhibidores , Metaloendopeptidasas/genética , Ratones , Ratones Noqueados , Fragmentos de Péptidos/metabolismoRESUMEN
The pleiotropic activities of the potent proinflammatory cytokine TNF are mediated by two structurally related, but functionally distinct, receptors, p55 and p75, that are coexpressed on most cell types. The majority of biologic responses classically attributed to TNF are mediated by p55. In contrast, p75 has been proposed to function as both a TNF antagonist by neutralizing TNF and as a TNF agonist by facilitating the interaction between TNF and p55 at the cell surface. We have examined the roles of p55 and p75 in mediating and modulating the activity of TNF in vivo by generating and examining mice genetically deficient in these receptors. Selective deficits in several host defense and inflammatory responses are observed in mice lacking p55 or both p55 and p75, but not in mice lacking p75. In these models, the activity of p55 is not impaired by the absence of p75, arguing against a physiologic role for p75 as an essential element of p55-mediated signaling. In contrast, exacerbated pulmonary inflammation and dramatically increased endotoxin induced serum TNF levels in mice lacking p75 suggest a dominant role for p75 in suppressing TNF-mediated inflammatory responses. In summary, these data help clarify the biologic roles of p55 and p75 in mediating and modulating the biologic activity of TNF and provide genetic evidence for an antagonistic role of p75 in vivo.
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Antígenos CD/metabolismo , Antígenos CD/fisiología , Inflamación/inmunología , Receptores del Factor de Necrosis Tumoral/metabolismo , Receptores del Factor de Necrosis Tumoral/fisiología , Reacción de Fase Aguda/genética , Reacción de Fase Aguda/inmunología , Animales , Antígenos CD/sangre , Antígenos CD/genética , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Cruzamientos Genéticos , Modelos Animales de Enfermedad , Endotoxemia/genética , Endotoxemia/inmunología , Endotoxemia/mortalidad , Pulmón de Granjero/genética , Pulmón de Granjero/inmunología , Pulmón de Granjero/patología , Femenino , Inmunidad Innata , Inflamación/genética , Listeriosis/inmunología , Subgrupos Linfocitarios/citología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Ratones Endogámicos , Ratones Noqueados , Receptores del Factor de Necrosis Tumoral/sangre , Receptores del Factor de Necrosis Tumoral/genética , Receptores Tipo I de Factores de Necrosis Tumoral , Receptores Tipo II del Factor de Necrosis Tumoral , Timo/citología , Timo/crecimiento & desarrollo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Mammalian cells proteolytically release (shed) the extracellular domains of many cell-surface proteins. Modification of the cell surface in this way can alter the cell's responsiveness to its environment and release potent soluble regulatory factors. The release of soluble tumour-necrosis factor-alpha (TNF-alpha) from its membrane-bound precursor is one of the most intensively studied shedding events because this inflammatory cytokine is so physiologically important. The inhibition of TNF-alpha release (and many other shedding phenomena) by hydroxamic acid-based inhibitors indicates that one or more metalloproteinases is involved. We have now purified and cloned a metalloproteinase that specifically cleaves precursor TNF-alpha. Inactivation of the gene in mouse cells caused a marked decrease in soluble TNF-alpha production. This enzyme (called the TNF-alpha-converting enzyme, or TACE) is a new member of the family of mammalian adamalysins (or ADAMs), for which no physiological catalytic function has previously been identified. Our results should facilitate the development of therapeutically useful inhibitors of TNF-alpha release, and they indicate that an important function of adamalysins may be to shed cell-surface proteins.
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Desintegrinas/metabolismo , Metaloendopeptidasas/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Proteínas ADAM , Proteína ADAM17 , Secuencia de Aminoácidos , Animales , Bovinos , Membrana Celular/metabolismo , Clonación Molecular , Precursores Enzimáticos/metabolismo , Marcación de Gen , Humanos , Metaloendopeptidasas/genética , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Solubilidad , Linfocitos T/enzimología , Células Tumorales Cultivadas , Zinc/metabolismoRESUMEN
The ligand for the receptor tyrosine kinase fms-like tyrosine kinase 3 (flt3), also referred to as fetal liver kinase-2 (flk-2), has an important role in hematopoiesis. The flt3 ligand (flt3L) is a growth factor for hematopoietic progenitors and induces hematopoietic progenitor and stem cell mobilization in vivo. In addition, when mice are treated with flt3L immature B cells, natural killer (NK) cells and dendritic cells (DC) are expanded in vivo. To further elucidate the role of flt3L in hematopoiesis, mice lacking flt3L (flt3L-/-) were generated by targeted gene disruption. Leukocyte cellularity was reduced in the bone marrow, peripheral blood, lymph nodes (LN), and spleen. Thymic cellularity, blood hematocrit, and platelet numbers were not affected. Significantly reduced numbers of myeloid and B-lymphoid progenitors were noted in the BM of flt3L-/- mice. In addition a marked deficiency of NK cells in the spleen was noted. DC numbers were also reduced in the spleen, LN, and thymus. Both myeloid-related (CD11c(++) CD8alpha(-)) and lymphoid-related (CD11c(++) CD8alpha(+)) DC numbers were affected. We conclude that flt3L has an important role in the expansion of early hematopoietic progenitors and in the generation of mature peripheral leukocytes.