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1.
Int J Food Microbiol ; 426: 110892, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39241545

RESUMEN

LED technology has emerged as a promising non-thermal preservation method for highly perishable muscle foods like meat and fish. Muscle foods are most susceptible to spoilage due to their high moisture content and nutrient density, which create an ideal environment for microbial growth, chemical oxidation, and enzymatic activity, which negatively alter their quality. LED treatment offers an effective solution by significantly reducing microbial loads and extending shelf life without adversely affecting sensory and nutritional properties. Specific wavelengths of LED light induce microbial inactivation through mechanisms like DNA damage, lipid oxidation, and protein alteration. Studies have shown that LED treatment can preserve the fresh-like quality of muscle foods by mitigating common spoilage processes. The advantages of LED technology include its non-thermal nature, ability to integrate with other preservation methods, and controllability in terms of intensity and wavelength. This enables for tailored applications based on food type and spoilage risks. As consumer demand grows for safe, chemical-free food options, LED technology addresses this need while enhancing food safety and quality. Further research is encouraged to optimize LED applications in various muscle food preservation contexts. With its exceptional ability to produce DNA damage in bacteria, inactivate enzymes, and malfunction biological activities, LED could serve as an inexpensive processing intervention to safeguard the quality of meat and seafood products. This review underscores the potential of LED technology as a promising alternative to traditional preservation methods for decontamination of muscle food.

2.
Acta Orthop Belg ; 82(2): 649-655, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-29119909

RESUMEN

The purpose was to analyse two reported risk factors on the outcome of Birmingham hip resurfacing (BHR). We reviewed consecutive BHR arthroplasties and found 1,476 cases eligible for analysis. The mean follow-up was 7.3 years. Patients were classified into groups according to their head size and body mass index (BMI). Statistical analysis examined the follow-up Oxford Hip Scores (OHS) and revision rates between groups. In the large head group (50mm and above) the OHS was 0.5 points higher (p=0.003) than the small head group. In the non-obese group (BMI <30) it was 0.3 points higher (p=0.007). No significant difference in the survival of the implants by either head size or by BMI was detected. BHR is a suitable option offering good survival and higher functional outcomes in non-obese patients (BMI<30) with larger femoral head diameters (50 and above). Although results are statistically significant such a small difference in OHS will rarely show significant clinical difference. Therefore, despite.


Asunto(s)
Artroplastia de Reemplazo de Cadera/métodos , Hilos Ortopédicos , Fracturas del Radio/etiología , Niño , Prótesis de Cadera , Humanos , Falla de Prótesis , Estudios Retrospectivos , Resultado del Tratamiento
3.
Acta Orthop Belg ; 82(4): 681-689, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29182107

RESUMEN

The indications for Kirschner wiring, the technique of wiring, type of cast immobilization, period of immobilization and complications of K wires are unclear. We conducted a systematic review of the literature on Kirschner wiring of distal radius fractures in children. A total of 4263 articles were identified. The full text of the remaining 78 articles was reviewed. 64 articles were finally excluded because of incomplete data leaving 14 for analysis. Complete fracture displacement and translation more than 50% are the commonest indications for Kirschner wiring of these fractures with 2 retrograde wires in non-Kapandji fashion being the commonest technique. Long arm casts are the favored modality of immobilization with superficial infection being the commonest complication. Re-displacement rates are low after Kirschner wiring. Most studies were retrospective and there is the need for a multicenter randomized controlled trial to define protocols for management of displaced distal radius fractures in children.


Asunto(s)
Moldes Quirúrgicos , Fijación Interna de Fracturas/métodos , Inmovilización , Fracturas del Radio/cirugía , Infección de la Herida Quirúrgica/epidemiología , Adolescente , Hilos Ortopédicos , Niño , Preescolar , Humanos , Lactante , Recién Nacido
4.
Acta Orthop Belg ; 82(4): 829-835, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-29182125

RESUMEN

The purpose of this study is to present our experience of treating adolescent femoral fractures using a locked intramedullary nail with a lateral trochanteric entry point. We retrospectively reviewed 15 femoral fractures in 13 adolescents who were treated in our unit between 2011 and 2014. Data collected included patient demographics, mechanism of injury, type of fracture, associated injuries, time to union and complications. A radiographic review was also undertaken. The mean time to radiological union in 14 out of the 15 fractures was 13 weeks (range, 10-20 weeks). One patient had a delayed union that required bone grafting and united finally at 30 weeks post injury. The mean difference in the neck shaft angle between the operated and non-operated side was 1.5 degrees (range : -10 to 10 degrees). No patients had infection or avascular necrosis. Five nails were removed after the fractures had healed without complications. Locked rigid intramedullary nailing of adolescent femoral fractures is a safe and effective treatment option when the lateral aspect of the greater trochanter is used as an entry point.


Asunto(s)
Clavos Ortopédicos , Fracturas del Fémur/cirugía , Fijación Intramedular de Fracturas , Adolescente , Fémur , Humanos , Estudios Retrospectivos , Resultado del Tratamiento
5.
Acta Orthop Belg ; 82(4): 896-900, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29182136

RESUMEN

PURPOSE: The purpose of this study is to report our experience of fractures in children riding Hoverboards. METHODS: We undertook a prospective review of all children attending our hospital who sustained fractures whilst riding a Hoverboard. Data such as patient demographics, type of fracture sustained, treatment received, complications and outcome were collected. RESULTS: Twelve children, 5 males and 7 females with ages ranging from 5.5 to 15.3 years were included in this study. All patients sustained upper limb fractures and the distal radius was the commonest fracture site (30%). Surgery was required in 6 (50%) out of the 12 patients because the respective fractures were displaced. No patient had any ongoing complaints or disability at the last clinic review.   Conclusion : Children riding Hoverboards are predisposed to upper limb fractures and parents who purchase Hoverboards should be warned about this.


Asunto(s)
Fracturas del Húmero/epidemiología , Fracturas del Radio/epidemiología , Patinación/lesiones , Adolescente , Hilos Ortopédicos , Moldes Quirúrgicos , Niño , Preescolar , Reducción Cerrada , Femenino , Fijación Interna de Fracturas , Humanos , Fracturas del Húmero/terapia , Inmovilización , Masculino , Reducción Abierta , Estudios Prospectivos , Fracturas del Radio/terapia , Extremidad Superior/lesiones
6.
Plant Dis ; 91(10): 1212-1220, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30780511

RESUMEN

Viruslike chlorotic ring spot symptoms and line patterns of unknown origin were observed on a greenhouse-grown turnip plant. The suspected virus was mechanically transmissible to plants in the Brassicaceae. Electron microscopic analysis revealed icosahedral particles approximately 28 nm in diameter. Reverse transcriptase-polymerase chain reaction (RT-PCR) analyses suggested that the pathogen is a comovirus, an observation that was confirmed by analysis of portions of the genomic sequence. This virus was provisionally named Turnip ringspot virus (TuRSV). Based on the RNA 1 sequence, TuRSV is most similar to Radish mosaic virus, another pathogen that infects members of the Brassicaceae. Arabidopsis thaliana is susceptible to TuRSV, and 12 out of the 23 ecotypes studied showed symptoms when inoculated with the virus. TuRSV induced a variety of responses on ecotypes from death to no infection. Some ecotypes showed one or two rounds of symptom display followed by recovery when inoculated with TuRSV. About half of the ecotypes (11/23) analyzed showed no symptoms when inoculated with TuRSV. Col-0 plants showed no symptoms, and infectious virus was not recovered from systemic leaves, although it could be detected by RT-PCR. Col-0 plants harboring mutations impairing the ethylene, jasmonic acid, or salicylic acid signaling pathways did not show symptoms when inoculated with TuRSV.

7.
Protein Expr Purif ; 23(2): 301-10, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11676606

RESUMEN

CD40-CD154 (CD40 ligand) interactions are essential for the development of protective immunity. Previous studies have described the CD40 binding site as a shallow groove formed between two monomers of CD154. However, these studies have not examined the structure or biological function of the carbohydrate on CD154. Human CD154 contains a single N-linked glycosylation site at asparagine 240. We have characterized the interactions between CD40 and soluble (s) CD154 in which sCD154 contains different types of carbohydrates. Detailed carbohydrate analysis revealed high-mannose structures on sCD154 purified from Pichia pastoris, whereas CD154 purified from Chinese hamster ovary E1A contained heterogeneous populations of complex carbohydrates. sCD154 purified from either system was trimeric, it bound to CD40 with similar affinities of 10-30 nM, and it functionally induced CD69 and CD95 expression on primary B cells. Together, these results indicate that the presence of varied types of N-linked glycans on asparagine 240 of CD154 does not play a significant role in the CD40-CD154 interactions.


Asunto(s)
Antígenos CD40/química , Ligando de CD40/química , Carbohidratos/química , Animales , Asparagina/química , Linfocitos B/inmunología , Antígenos CD40/genética , Antígenos CD40/inmunología , Antígenos CD40/metabolismo , Ligando de CD40/genética , Ligando de CD40/inmunología , Ligando de CD40/metabolismo , Células CHO , Conformación de Carbohidratos , Metabolismo de los Hidratos de Carbono , Células Cultivadas , Clonación Molecular , Cricetinae , Humanos , Manosa/química , Manosa/metabolismo , Pichia/genética , Unión Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Solubilidad
8.
Protein Expr Purif ; 22(2): 330-6, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11437610

RESUMEN

CD23, a 45-kDa type II membrane glycoprotein present on B cells, monocytes, and other human immune cells, is a low-affinity receptor for IgE. The extracellular region of the membrane-bound human CD23 is processed into at least four soluble (s) CD23 forms, with apparent molecular masses of 37, 33, 29, and 25 kDa. High levels of sCD23 are found in patients with allergy, certain autoimmune diseases, or chronic lymphocytic leukemia. Therefore, inhibition of the processing of membrane-bound CD23 to control the cytokine-like effects of sCD23 offers a novel therapeutic opportunity. While the 37-, 29-, and 25-kDa forms of sCD23 have been expressed previously as recombinant proteins, the 33-kDa form has not been purified and characterized. To further investigate the multiple roles of sCD23 fragments and to devise assays to identify potent small-molecule inhibitors of CD23 processing, we have produced the 33-kDa form of sCD23 using Chinese hamster ovary (CHO) and Drosophila S2 cells. The CHO-expressed 33-kDa protein was found to undergo proteolytic degradation during cell growth and during storage of purified protein, resulting in accumulation of a 25-kDa form. The Drosophila system expressed the 33-kDa sCD23 in a stable form that was purified and demonstrated to be more active than the CHO-derived 25-kDa form in a monocyte TNFalpha release assay.


Asunto(s)
Drosophila/genética , Receptores de IgE/genética , Receptores de IgE/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Células CHO , Línea Celular , Clonación Molecular , Cricetinae , Drosophila/citología , Vectores Genéticos , Humanos , Datos de Secuencia Molecular , Peso Molecular , Monocitos/metabolismo , Receptores de IgE/biosíntesis , Receptores de IgE/metabolismo , Solubilidad , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Factor de Necrosis Tumoral alfa/metabolismo
9.
J Biol Chem ; 276(32): 30024-30, 2001 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-11375394

RESUMEN

In the bacterial type II fatty acid synthase system, beta-ketoacyl-acyl carrier protein (ACP) synthase III (FabH) catalyzes the condensation of acetyl-CoA with malonyl-ACP. We have identified, expressed, and characterized the Streptococcus pneumoniae homologue of Escherichia coli FabH. S. pneumoniae FabH is approximately 41, 39, and 38% identical in amino acid sequence to Bacillus subtilis, E. coli, and Hemophilus influenzae FabH, respectively. The His-Asn-Cys catalytic triad present in other FabH molecules is conserved in S. pneumoniae FabH. The apparent K(m) values for acetyl-CoA and malonyl-ACP were determined to be 40.3 and 18.6 microm, respectively. Purified S. pneumoniae FabH preferentially utilized straight short-chain CoA primers. Similar to E. coli FabH, S. pneumoniae FabH was weakly inhibited by thiolactomycin. In contrast, inhibition of S. pneumoniae FabH by the newly developed compound SB418011 was very potent, with an IC(50) value of 0.016 microm. SB418011 also inhibited E. coli and H. influenzae FabH with IC(50) values of 1.2 and 0.59 microm, respectively. The availability of purified and characterized S. pneumoniae FabH will greatly aid in structural studies of this class of essential bacterial enzymes and facilitate the identification of small molecule inhibitors of type II fatty acid synthase with the potential to be novel and potent antibacterial agents active against pathogenic bacteria.


Asunto(s)
3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/química , Streptococcus pneumoniae/enzimología , 3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/antagonistas & inhibidores , 3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/genética , Secuencia de Aminoácidos , Antibacterianos/farmacología , Asparagina/química , Catálisis , Cromatografía , Dicroismo Circular , Clonación Molecular , Cisteína/química , Relación Dosis-Respuesta a Droga , Electroforesis en Gel de Poliacrilamida , Inhibidores Enzimáticos/farmacología , Guanidina/farmacología , Histidina/química , Indoles/farmacología , Concentración 50 Inhibidora , Focalización Isoeléctrica , Cinética , Modelos Químicos , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Especificidad por Sustrato , Tiofenos/farmacología , Rayos Ultravioleta
10.
J Immunol ; 165(8): 4397-404, 2000 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-11035077

RESUMEN

The TNF receptor (TNFR) family plays a central role in the development of the immune response. Here we describe the reciprocal regulation of the recently identified TNFR superfamily member herpes virus entry mediator (HVEM) (TR2) and its ligand LIGHT (TL4) on T cells following activation and the mechanism of this process. T cell activation resulted in down-regulation of HVEM and up-regulation of LIGHT, which were both more pronounced in CD8(+) than CD4(+) T lymphocytes. The analysis of HVEM and LIGHT mRNA showed an increase in the steady state level of both mRNAs following stimulation. LIGHT, which was present in cytoplasm of resting T cells, was induced both in cytoplasm and at the cell surface. For HVEM, activation resulted in cellular redistribution, with its disappearance from cell surface. HVEM down-regulation did not rely on de novo protein synthesis, in contrast to the partial dependence of LIGHT induction. Matrix metalloproteinase inhibitors did not modify HVEM expression, but did enhance LIGHT accumulation at the cell surface. However, HVEM down-regulation was partially blocked by a neutralizing mAb to LIGHT or an HVEM-Fc fusion protein during activation. As a model, we propose that following stimulation, membrane or secreted LIGHT binds to HVEM and induces receptor down-regulation. Degradation or release of LIGHT by matrix metalloproteinases then contributes to the return to baseline levels for both LIGHT and HVEM. These results reveal a self-regulating ligand/receptor system that contributes to T cell activation through the interaction of T cells with each other and probably with other cells of the immune system.


Asunto(s)
Regulación hacia Abajo/inmunología , Activación de Linfocitos , Proteínas de la Membrana/biosíntesis , Receptores del Factor de Necrosis Tumoral/antagonistas & inhibidores , Receptores del Factor de Necrosis Tumoral/biosíntesis , Receptores Virales/antagonistas & inhibidores , Receptores Virales/biosíntesis , Simplexvirus/inmunología , Subgrupos de Linfocitos T/metabolismo , Factor de Necrosis Tumoral alfa/biosíntesis , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/virología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/virología , Separación Celular , Células Cultivadas , Cicloheximida/farmacología , Inhibidores Enzimáticos/farmacología , Humanos , Ligandos , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/fisiología , Metaloendopeptidasas/antagonistas & inhibidores , Metaloendopeptidasas/fisiología , Microscopía Confocal , Inhibidores de la Síntesis de la Proteína/farmacología , ARN Mensajero/metabolismo , Receptores del Factor de Necrosis Tumoral/genética , Receptores del Factor de Necrosis Tumoral/metabolismo , Miembro 14 de Receptores del Factor de Necrosis Tumoral , Receptores Virales/genética , Receptores Virales/metabolismo , Subgrupos de Linfocitos T/efectos de los fármacos , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/virología , Miembro 14 de la Superfamilia de Ligandos de Factores de Necrosis Tumoral , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Regulación hacia Arriba/inmunología
11.
Gastrointest Endosc ; 52(4): 500-5, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11023567

RESUMEN

BACKGROUND: Manipulation of the duodenal papilla may lead to symptomatic stenosis of the orifices of bile duct, main pancreatic duct or accessory pancreatic duct. METHODS: Seventeen patients with stenosis of the orifice (bile duct 7, bile duct/main pancreatic duct 7, accessory pancreatic duct 3) underwent sphincterotomy and/or dilation and stent placement for a median of 140 days (range 30 to 1080 days). Patients were interviewed at a median of 720 days (range 120 to 990 days) after removal of the final stent. RESULTS: Median age was 50 years (range 17 to 68 years); 78% were women. The etiology of stenosis of the orifice was sphincterotomy in 8, sphincteroplasty in 7 and papillectomy in 2 patients. Indications for treatment were abdominal pain (100%), dilated bile duct and/or main pancreatic duct (14 patients) and pancreas divisum (3 patients). Sixty procedures (median 4 per patient) were performed with mild morbidity (hospital stay less than 3 days) in 17% of procedures and 35% of patients. Symptoms improved in 100%, 57% and 33% of patients with bile duct, bile duct/main pancreatic duct and accessory pancreatic duct, respectively. Surgery was ultimately needed in 3 (43%) patients with bile duct/main pancreatic duct and 2 (67%) with accessory pancreatic duct stenosis. CONCLUSIONS: Endoscopic therapy successfully relieves pain due to biliary stenosis of the orifice but less frequently relieves pain due to pancreatic stenosis of the orifice.


Asunto(s)
Colangiopancreatografia Retrógrada Endoscópica , Colestasis/terapia , Conductos Pancreáticos/patología , Adolescente , Adulto , Anciano , Colestasis/diagnóstico , Constricción Patológica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos
12.
Clin Exp Allergy ; 30(5): 719-27, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10792365

RESUMEN

BACKGROUND: CD23, the low affinity serum immunoglobulin E (IgE) receptor, is upregulated on B cells following interleukin (IL)-4 stimulation and is concomitantly cleaved to generate soluble CD23 (sCD23) fragments with cytokine-like activity. OBJECTIVE: Compounds that selectively inhibit the proteolytic release of CD23 to generate sCD23 were assessed for their ability to inhibit IgE production in order to evaluate the contribution of sCD23 in the production of human IgE as well as the ability of such compounds to block IgE production. METHODS: IgE production was measured in IL-4-stimulated human peripheral blood lymphocytes (PBL) and PBL-reconstituted SCID mice in the presence of a broad-spectrum matrix metalloprotease (MMP) inhibitor, a compound selective for inhibition of CD23 processing over MMPs and an anti-CD23 mAb, MHM6. RESULTS: The two compounds were equipotent in inhibiting IgE production without inhibition of IgG production by IL-4/anti-CD40-stimulated PBL. Soluble CD23 release was also shown to precede IgE accumulation in the cell-free medium. Addition of compound at later times other than day 0 in the 14 day assay resulted in progressively less inhibition of both IgE and sCD23, and exactly paralleled the effect of an anti-CD23 mAb, MHM6 on IgE levels. Both compounds also inhibited the release of CD23 from human RPMI 8866 cells adoptively transferred i. p. to mice. Doses required for inhibition of CD23 correlated well with the doses required for inhibition of IgE production in IL-4-challenged hu-PBL-SCID mice. IgE was selectively inhibited over total IgG in the SCID mice as well. CONCLUSIONS: Inhibition of CD23 processing alone is sufficient to inhibit IL-4-stimulated IgE production both in vitro and in vivo.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Inmunoglobulina E/biosíntesis , Inmunosupresores/farmacología , Interleucina-4/antagonistas & inhibidores , Interleucina-4/fisiología , Linfocitos/metabolismo , Procesamiento Proteico-Postraduccional/inmunología , Receptores de IgE/antagonistas & inhibidores , Animales , Quimera , Humanos , Transfusión de Linfocitos , Linfocitos/efectos de los fármacos , Linfocitos/inmunología , Inhibidores de la Metaloproteinasa de la Matriz , Ratones , Ratones SCID , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/metabolismo , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Receptores de IgE/metabolismo , Solubilidad
13.
J Biol Chem ; 275(30): 23319-25, 2000 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-10770955

RESUMEN

TRAIL is a member of the tumor necrosis factor (TNF) family of cytokines which induces apoptotic cell death in a variety of tumor cell lines. It mediates its apoptotic effects through one of two receptors, DR4 and DR5, which are members of of the TNF receptor family, and whose cytoplasmic regions contain death domains. In addition, TRAIL also binds to 3 "decoy" receptors, DcR2, a receptor with a truncated death domain, DcR1, a glycosylphosphatidylinositol-anchored receptor, and OPG a secreted protein which is also known to bind to another member of the TNF family, RANKL. However, although apoptosis depends on the expression of one or both of the death domain containing receptors DR4 and/or DR5, resistance to TRAIL-induced apoptosis does not correlate with the expression of the "decoy" receptors. Previously, TRAIL has been described to bind to all its receptors with equivalent high affinities. In the present work, we show, by isothermal titration calorimetry and competitive enzyme-linked immunosorbent assay, that the rank order of affinities of TRAIL for the recombinant soluble forms of its receptors is strongly temperature dependent. Although DR4, DR5, DcR1, and OPG show similar affinities for TRAIL at 4 degrees C, their rank-ordered affinities are substantially different at 37 degrees C, with DR5 having the highest affinity (K(D)

Asunto(s)
Glicoproteínas de Membrana/metabolismo , Receptores del Factor de Necrosis Tumoral/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis , Secuencia de Bases , Células CHO , Calorimetría , Cricetinae , Cartilla de ADN , Humanos , Glicoproteínas de Membrana/genética , Pichia/genética , Unión Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF , Temperatura , Factor de Necrosis Tumoral alfa/genética
14.
Biochem Biophys Res Commun ; 270(1): 100-7, 2000 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-10733911

RESUMEN

Bacterial beta-ketoacyl-acyl carrier protein (ACP) synthase III (KAS III, also called FabH) catalyzes the condensation and transacylation of acetyl-CoA with malonyl-ACP. In order to understand the mode of enzyme/substrate interaction and design small molecule inhibitors, we have expressed, purified, and crystallized a selenomethionyl-derivative of E. coli KAS III. Several lines of evidence confirmed that purified selenomethionyl KAS III was homogenous, stably folded, and enzymatically active. Dynamic light scattering, size exclusion chromatography, and mass spectrometry results indicated that selenomethionyl KAS III is a noncovalent homodimer. Diffraction quality crystals of selenomethionyl KAS III/acetyl-CoA complex, which grew overnight to a size of 0.2 mm(3), belonged to the tetragonal space group P4(1)2(1)2.


Asunto(s)
3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/química , Acetilcoenzima A/química , Escherichia coli/enzimología , Selenometionina/química , 3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/biosíntesis , 3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/genética , Cromatografía en Gel , Dicroismo Circular , Cristalización , Escherichia coli/genética , Espectrometría de Masas , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Selenometionina/metabolismo
15.
J Biol Chem ; 274(51): 36465-71, 1999 Dec 17.
Artículo en Inglés | MEDLINE | ID: mdl-10593943

RESUMEN

Beta-ketoacyl-acyl carrier protein synthase III (FabH), the most divergent member of the family of condensing enzymes, is a key catalyst in bacterial fatty acid biosynthesis and a promising target for novel antibiotics. We report here the crystal structures of FabH determined in the presence and absence of acetyl-CoA. These structures display a fold that is common for condensing enzymes. The observed acetylation of Cys(112) proves its catalytic role and clearly defines the primer binding pocket. Modeling based on a bound CoA molecule suggests catalytic roles for His(244) and Asn(274). The structures provide the molecular basis for FabH substrate specificity and reaction mechanism and are important for structure-based design of novel antibiotics.


Asunto(s)
3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/química , Proteínas Bacterianas/química , Isoenzimas/química , 3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/metabolismo , Proteínas Bacterianas/metabolismo , Escherichia coli , Ácidos Grasos/metabolismo , Isoenzimas/metabolismo , Datos de Secuencia Molecular , Conformación Proteica , Especificidad por Sustrato
16.
Eur J Nucl Med ; 26(3): 215-9, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10079310

RESUMEN

A total of 20 ventilation studies [16 with xenon-133 and four with technetium-99m diethylenetriamine pentaacetic acid (DTPA)] were performed in 11 patients with suspected post-pneumonectomy bronchopleural fistulae. The findings on the ventilation scan were correlated with bronchoscopy, taken as the gold standard for purposes of comparison. The sensitivity and specificity for 133Xe scans were 83% and 100% respectively, while the sensitivity for 99mTc-DTPA aerosol studies was poor at 0%. Special techniques for optimal visualization of the fistulae are enumerated.


Asunto(s)
Fístula Bronquial/diagnóstico por imagen , Fístula/diagnóstico por imagen , Enfermedades Pleurales/diagnóstico por imagen , Neumonectomía/efectos adversos , Aerosoles , Fístula Bronquial/etiología , Broncoscopía , Femenino , Fístula/etiología , Humanos , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Enfermedades Pleurales/etiología , Cintigrafía , Radiofármacos , Sensibilidad y Especificidad , Pentetato de Tecnecio Tc 99m , Radioisótopos de Xenón
17.
J R Coll Physicians Lond ; 32(4): 354-7, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9762631

RESUMEN

BACKGROUND: Surgery and balloon dilatation are perceived by many as the principal treatments for peptic pyloric stenosis. We questioned whether, with the availability of modern acid suppressant treatment, this was still appropriate or whether patients could be managed with medical treatment alone. METHODS: Seventeen consecutive patients with peptic pyloric stenosis were treated with endoscopic gastric drainage, followed by oral omeprazole in 15 or cimetidine in two. Gastric emptying half times for solids and liquids were assessed in 11 of the 17 patients when they had become asymptomatic. RESULTS: Endoscopic drainage and medical treatment successfully relieved symptoms in all 17 patients, although the gastric emptying studies in 11 patients still showed prolongation in eight. Symptoms resolved completely after a mean of 28 days. Five patients relapsed when changed from omeprazole to cimetidine treatment, but all responded to re-starting omeprazole. Four patients remain well on cimetidine alone. CONCLUSIONS: Medical treatment preceded by endoscopic gastric drainage was effective in all patients in this series and may be the preferred choice of treatment in patients with pyloric stenosis.


Asunto(s)
Antiulcerosos/uso terapéutico , Cimetidina/uso terapéutico , Antagonistas de los Receptores H2 de la Histamina/uso terapéutico , Omeprazol/uso terapéutico , Úlcera Péptica/complicaciones , Estenosis Pilórica/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Vaciamiento Gástrico/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Estenosis Pilórica/etiología , Estenosis Pilórica/fisiopatología
18.
Int Immunol ; 10(1): 27-35, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9488153

RESUMEN

In order to evaluate the potential of TCR as vaccines for immunomodulation, the immunogenicity of soluble versions of D10 TCR has been investigated in mice. Soluble D10 TCR containing the extracellular domains were produced either as dual chain (dc) TCR lacking transmembrane and cytoplasmic regions or as a TCR-IgG1 chimeric protein. Soluble single chain (sc) D10 TCR contained only the Valpha and Vbeta segments joined by a peptide linker. Syngeneic D10 dcTCR or D10 TCR-IgG1 immunizations of AKR mice induced antibody responses to D10 clonotypic epitopes and to constant region epitopes that are not exposed on D10 cells. Only clonotypic antibodies were produced after D10 scTCR immunizations. Immunization of AKR mice with D10 dcTCR and D10 TCR-IgG1 primed I-Ak- and I-Ek-restricted CD4+ T cells recognizing constant region epitopes, but there was no detectable response to the variable region. Comparison of the in vitro proliferative responses of CD4+ T cells from D10 scTCR-primed H-2 congenic mice revealed that H-2u was a responder haplotype for the variable region. How the immunogenicity of particular regions of the TCR appears to be shaped by tolerance induction in vivo and the implications for immunotherapy with soluble TCR vaccinations are discussed.


Asunto(s)
Activación de Linfocitos/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T/inmunología , Adyuvantes Inmunológicos/farmacología , Secuencia de Aminoácidos , Animales , Formación de Anticuerpos/inmunología , Inmunoglobulina G/inmunología , Ratones , Ratones Endogámicos , Datos de Secuencia Molecular , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/farmacología , Solubilidad , Vacunas/inmunología , Vacunas/farmacología
19.
J Immunol Methods ; 206(1-2): 163-9, 1997 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-9328579

RESUMEN

For structural studies, high-level production of properly folded, disulfide-linked, unglycosylated protein in E. coli is an attractive alternative to production in eukaryotic systems. We describe here the production of heterodimeric, murine D10 T-cell receptor (sD10TCR) in E. coli as a secreted leucine zipper (LZ) fusion protein. Two genes, one (alpha-acid) encoding the alpha-chain variable and constant domains (V alpha and C alpha) of D10 TCR fused to an LZ 'acid' encoding sequence and the other (beta-base) encoding the beta-chain variable and constant domains (V beta and C beta) fused to an LZ 'base' encoding sequence, were co-expressed from a bacteriophage T7 promoter as a dicistronic message. Secreted alpha-acid and beta-base proteins formed proper inter- and intra-chain disulfide bonds in the periplasm, bypassing the need for in vitro protein refolding. Complementary LZ sequences facilitated the formation of alpha beta heterodimers. sD10TCR-LZ was purified by affinity chromotography using a D10 TCR clonotype-specific monoclonal antibody (mAb 3D3). Typical yields of purified protein were 4-5 mg/l of culture. Purified sD10TCR-LZ was reactive with a panel of conformationally sensitive TCR-specific monoclonal antibodies, consistent with its conformational integrity and appeared to be suitable for structural studies by X-ray crystallography or NMR spectroscopy.


Asunto(s)
Escherichia coli/genética , Receptores de Antígenos de Linfocitos T alfa-beta/biosíntesis , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/metabolismo , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/química , Reacciones Antígeno-Anticuerpo , Dimerización , Escherichia coli/inmunología , Leucina Zippers/genética , Leucina Zippers/inmunología , Ratones , Datos de Secuencia Molecular , Receptores de Antígenos de Linfocitos T alfa-beta/química , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes de Fusión/aislamiento & purificación , Solubilidad
20.
J Nucl Med ; 38(4): 582-6, 1997 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9098206

RESUMEN

UNLABELLED: Multidetector SPECT systems equipped with a high-energy, or 511-keV collimator, have been proposed to offer a less expensive alternative to PET in myocardial viability studies with [18F]FDG. The objectives of this investigation included: (a) measuring the physical imaging characteristics of SPECT systems equipped with either a high-energy general-purpose collimator (HE), or the dedicated 511-keV collimator (UH), when imaging 511-keV photons, and comparing them with conventional FDG PET; and (b) directly and quantitatively comparing the diagnostic accuracy of SPECT, with either an UH or HE collimator, to that of PET in myocardial viability studies using 18F-FDG. METHODS: Physical imaging characteristics of SPECT and PET were measured and compared. Both SPECT and PET studies were performed in two groups of 18 patients each, with Group I using HE SPECT and Group II using UH SPECT. Myocardial perfusion studies were also performed using 82Rb PET at rest and during dipyridamole stress to identify areas of persistent hypoperfusion. For each myocardial region with a persistent perfusion defect, a perfusion-metabolism match or mismatch pattern was established independently, based on the results of 18F-FDG SPECT as well as PET. RESULTS: PET is superior to SPECT in all physical imaging characteristics, particularly in sensitivity and contrast resolution. PET had a sensitivity 40-80 times higher than that of SPECT, and its contrast resolution was 40-100% better than SPECT. Between FDG-SPECT using an HE collimator and that using a 511-keV collimator, the latter showed marked reduction in septal penetration (from 56% to 38%), improvement in spatial resolution (from 17 mm to 11 mm FWHM) as well as contrast resolution (from 34% to 45%), while suffering reduced system sensitivity (from 75 to 34 cpm/microCi). Patient studies demonstrated that although FDG-SPECT, using a HE or UH collimator, provided concordant viability information as FDG PET in a large majority of myocardial segments with persistent perfusion defects (88% and 90%, respectively), there is an excellent statistical agreement (kappa = 0.736) between SPECT with UH collimator and PET, while the agreement between SPECT using HE collimator and PET are moderate (kappa = 0.413). CONCLUSION: Despite its markedly inferior physical imaging characteristics compared with PET, SPECT with the dedicated 511-keV collimator offers a low-cost, practical alternative to PET in studying myocardial viability using [18F]FDG. SPECT systems with a high-energy, general-purpose collimator, on the other hand, are inadequate in such studies.


Asunto(s)
Desoxiglucosa/análogos & derivados , Radioisótopos de Flúor , Corazón/diagnóstico por imagen , Tomografía Computarizada de Emisión de Fotón Único , Tomografía Computarizada de Emisión , Circulación Coronaria , Fluorodesoxiglucosa F18 , Humanos , Radioisótopos de Rubidio , Sensibilidad y Especificidad
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