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1.
J Hand Surg Am ; 49(4): 337-345, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38310509

RESUMO

PURPOSE: This study aimed to assess both nonsurgical and operative treatment outcomes of pediatric and young adult patients with thoracic outlet syndrome (TOS) at a tertiary care pediatric hospital. METHODS: A retrospective chart review of patients diagnosed with TOS, who were seen between January 2010 and August 2022 at a tertiary care pediatric hospital, was conducted. Collected pre- and postoperative data included symptoms, provocative testing (ie, Roo's, Wright's, and Adson's tests), participation in sports or upper-extremity activities, additional operations, and surgical complications. Assessment of operative treatment efficacy was based on pre- and post-provocative testing, pain, venogram results, alleviation of symptoms, and return to previous activity level 6 months after surgery. RESULTS: Ninety-six patients, (70 females and 26 males) with an average age at onset of 15 ± 4 (4-25) years, met the inclusion criteria for TOS. Among them, 27 had neurogenic TOS, 29 had neurogenic and vasculogenic TOS, 20 had vasculogenic TOS, 19 had Paget-Schroetter Syndrome, and one was asymptomatic. Twenty-six patients were excluded because of less than 6 months of follow-up. Of the remaining 70, 6 (8.6%) patients (4 bilateral and 2 unilateral) underwent nonoperative management with activity modification and physical therapy only, and one was fully discharged because of complete relief of symptoms. Sixty-four (90.1%) patients (45 bilateral and 19 unilateral) underwent surgery. A total of 102 operations were performed. Substantial improvements were observed in provocative maneuvers after surgery. Before surgery, 79.7% were involved in sports or playing musical instruments with repetitive overhead activity, and after surgery, 86.2% of these patients returned to their previous activity level. CONCLUSIONS: Few patients were successfully managed with nonoperative activity modification and physical therapy. In those requiring surgical intervention, first or cervical rib resection with scalenectomy using a supraclavicular approach provided resolution of symptoms with 86.2% of patients being able to return to presymptom sport or activity level. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.


Assuntos
Procedimentos Ortopédicos , Síndrome do Desfiladeiro Torácico , Masculino , Feminino , Humanos , Adulto Jovem , Criança , Adolescente , Adulto , Estudos Retrospectivos , Descompressão Cirúrgica/métodos , Síndrome do Desfiladeiro Torácico/diagnóstico , Síndrome do Desfiladeiro Torácico/cirurgia , Resultado do Tratamento , Procedimentos Ortopédicos/efeitos adversos
3.
J Clin Med Res ; 11(1): 7-14, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30627272

RESUMO

BACKGROUND: Surgical volume has shifted significantly from inpatient to outpatient settings, including free-standing ambulatory surgery centers (ASCs). Approaches to quality improvement (QI) and surveillance used in hospitals are not always appropriate to the ambulatory setting. METHODS: We recruited 665 ASCs in 47 US states to participate in an intervention to improve safe practice through implementation of a surgical safety checklist and infection control practices. Areas for partner contribution included recruitment, project development, content development and delivery, clinical subject matter expertise, data analysis, and facility coaching. RESULTS: Barriers to implementation and data collection were encountered during the project, requiring revisions to the implementation plan. Project activities, such as facility recruitment, data measurement, and implementation strategies were modified to meet ASC-specific needs. Several ASC-specific tools were designed. CONCLUSIONS: The increasing number of patients being cared for in ASCs makes it essential to better understand how to implement quality improvement projects in that environment. Tailoring interventions to the ASC's unique needs is necessary.

4.
J Wildl Dis ; 53(2): 215-227, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28151078

RESUMO

We characterize Brucella infection in a wild southern sea otter ( Enhydra lutris nereis) with osteolytic lesions similar to those reported in other marine mammals and humans. This otter stranded twice along the central California coast, US over a 1-yr period and was handled extensively at two wildlife rehabilitation facilities, undergoing multiple surgeries and months of postsurgical care. Ultimately the otter was euthanized due to severe, progressive neurologic disease. Necropsy and postmortem radiographs revealed chronic, severe osteoarthritis spanning the proximal interphalangeal joint of the left hind fifth digit. Numerous coccobacilli within the joint were strongly positive on Brucella immunohistochemical labelling, and Brucella sp. was isolated in pure culture from this lesion. Sparse Brucella-immunopositive bacteria were also observed in the cytoplasm of a pulmonary vascular monocyte, and multifocal granulomas were observed in the spinal cord and liver on histopathology. Findings from biochemical characterization, 16S ribosomal DNA, and bp26 gene sequencing of the bacterial isolate were identical to those from marine-origin brucellae isolated from cetaceans and phocids. Although omp2a gene sequencing revealed 100% homology with marine Brucella spp. infecting pinnipeds, whales, and humans, omp2b gene sequences were identical only to pinniped-origin isolates. Multilocus sequence typing classified the sea otter isolate as ST26, a sequence type previously associated only with cetaceans. Our data suggest that the sea otter Brucella strain represents a novel marine lineage that is distinct from both Brucella pinnipedialis and Brucella ceti. Prior reports document the zoonotic potential of the marine brucellae. Isolation of Brucella sp. from a stranded sea otter highlights the importance of wearing personal protective equipment when handling sea otters and other marine mammals as part of wildlife conservation and rehabilitation efforts.


Assuntos
Brucella/patogenicidade , Lontras/microbiologia , Animais , Animais Selvagens , Brucella/isolamento & purificação , California , Caniformia
5.
Dis Aquat Organ ; 123(1): 1-11, 2017 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-28177288

RESUMO

A total of 31 sea otters Enhydra lutris nereis found dead or moribund (and then euthanized) were necropsied in California, USA. Stomach biopsies were collected and transected with equal portions frozen or placed in formalin and analyzed histologically and screened for Helicobacter spp. in gastric tissue. Helicobacter spp. were isolated from 9 sea otters (29%); 58% (18 of 31) animals were positive for helicobacter by PCR. The Helicobacter sp. was catalase- and oxidase-positive and urease-negative. By electron microscopy, the Helicobacter sp. had lateral and polar sheathed flagella and had a slightly curved rod morphology. 16S and 23S rRNA sequence analyses of all 'H. enhydrae' isolates had similar sequences, which clustered as a novel Helicobacter sp. closely related to H. mustelae (96-97%). The genome sequence of isolate MIT 01-6242 was assembled into a single ~1.6 Mb long contig with a 40.8% G+C content. The annotated genome contained 1699 protein-coding sequences and 43 RNAs, including 65 genes homologous to known Helicobacter spp. and Campylobacter spp. virulence factors. Histological changes in the gastric tissues extended from mild cystic degeneration of gastric glands to severe mucosal erosions and ulcers. Silver stains of infected tissues demonstrated slightly curved bacterial rods at the periphery of the gastric ulcers and on the epithelial surface of glands. The underlying mucosa and submucosa were infiltrated by low numbers of neutrophils, macrophages, and lymphocytes, with occasional lymphoid aggregates and well-defined lymphoid follicles. This is the second novel Helicobacter sp., which we have named 'H. enhydrae', isolated from inflamed stomachs of mustelids, the first being H. mustelae from a ferret.


Assuntos
Infecções por Helicobacter/veterinária , Helicobacter/classificação , Helicobacter/isolamento & purificação , Lontras , Gastropatias/veterinária , Animais , Genoma Bacteriano , Helicobacter/genética , Infecções por Helicobacter/microbiologia , Inflamação , Filogenia , Proteoma , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Gastropatias/microbiologia
6.
Behav Pharmacol ; 27(8): 697-703, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27661192

RESUMO

Despite moderate success with pharmacological and behavioral treatments, smoking relapse rates remain high, and many smokers report that smoking cues lead to relapse. Therefore, treatments that target cue reactivity are needed. One candidate for reducing craving is the neuropeptide oxytocin (OT). Here, we investigated the effects of intranasal OT on two types of craving for cigarettes: craving following overnight abstinence and craving elicited by smoking-related cues. In this within-subject, placebo-controlled pilot study, smokers (N=17) abstained from smoking for 12 h before attending two sessions randomized to intranasal OT or placebo (i.e. saline nasal spray). On each session, participants received two doses of OT (20 IU) or placebo at 1-h intervals, and rated craving before and after each dose. Spontaneous cigarette craving was assessed after the first spray, and cue-elicited craving was assessed following the second spray. OT did not reduce levels of spontaneous craving after the first spray, but significantly dampened cue-induced smoking craving. These results provide preliminary evidence that OT can reduce cue-induced smoking craving in smokers. These findings provide an important link between preclinical and clinical studies aimed at examining the effectiveness of OT as a novel treatment for drug craving.


Assuntos
Fissura/efeitos dos fármacos , Ocitocina/administração & dosagem , Fumantes/psicologia , Fumar/psicologia , Administração Intranasal , Adolescente , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino , Ocitocina/farmacologia , Projetos Piloto , Tabagismo/psicologia , Resultado do Tratamento , Adulto Jovem
7.
Artigo em Inglês | MEDLINE | ID: mdl-25838157

RESUMO

The Gram positive bacterial coccus Streptococcus infantarius subspecies coli is increasingly linked with development of fatal vegetative infective endocarditis and septicemia in humans, sea otters (Enhydra lutris) and other animals. However, the pathogenesis of these infections is poorly understood. Using S. infantarius subsp. coli strains isolated from sea otters with infective endocarditis, this study evaluated adherence and invasion of epithelial and endothelial cells, adherence to extracellular matrix components, and macrophage survival. Significant adherence to endothelial-derived cells was observed for 62% of isolates, 24% adhered to epithelial cell lines, and 95% invaded one or both cell types in vitro. The importance of the hyaluronic acid capsule in host cell adherence and invasion was also evaluated. Capsule removal significantly reduced epithelial adherence and invasion for most S. infantarius subsp. coli isolates, suggesting that the capsule facilitates attachment to and invasion of epithelium. Enzyme-linked immunosorbent assay testing revealed that all isolates adhered significantly to the extracellular matrix components collagen IV, fibronectin, laminin and hyaluronic acid. Finally, significant bacterial survival following phagocytosis by macrophages was apparent for 81% of isolates at one or more time points. Taken collectively these findings indicate that S. infantarius subsp. coli has multiple pathogenic properties that may be important to host colonization, invasion and disease.


Assuntos
Endocardite/veterinária , Macrófagos/microbiologia , Lontras/microbiologia , Streptococcus/isolamento & purificação , Streptococcus/patogenicidade , Animais , Aderência Bacteriana , Cápsulas Bacterianas/química , Cápsulas Bacterianas/fisiologia , Células CACO-2 , Linhagem Celular , Endocardite/microbiologia , Ensaio de Imunoadsorção Enzimática , Matriz Extracelular/química , Matriz Extracelular/fisiologia , Humanos , Ácido Hialurônico/análise , Camundongos , Viabilidade Microbiana , Streptococcus/classificação
8.
J Wildl Dis ; 51(2): 446-53, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25647597

RESUMO

The southern sea otter (Enhydra lutris nereis) is a threatened marine sentinel. During postmortem investigations of stranded sea otters from 2004 to 2013 in California, US, papillomas were detected in the oral cavity of at least seven otters via necropsy and histopathology. Next-generation sequencing of viral particles purified from a single papilloma revealed a novel papillomavirus, Enhydra lutris papillomavirus 1 (ElPV-1). The genome of ElPV-1 was obtained, representing the first fully sequenced viral genome from southern sea otters. Phylogenetic analysis of the entire L1 gene, as well as a concatenated protein identities plot of all papillomaviral genes revealed that ElPV-1 is a λ-papillomavirus, related to a raccoon papillomavirus (Procyon lotor papillomavirus type 1) and a canine oral papillomavirus. Immunohistochemical staining, using a cross-reactive bovine papillomavirus antibody, suggested that ElPV-1 is present in intranuclear inclusions and intracytoplasmic keratin granules. Virus-infected cells were scattered throughout the stratum granulosum and stratum spinosum of the gingival and buccal papillomas. Using ElPV-1-specific PCR, we confirmed viral DNA in oral papillomas from all seven stranded sea otters, with identical L1 sequences. This virus is associated with the development of oral papillomatosis in southern sea otters.


Assuntos
Doenças da Boca/veterinária , Lontras , Papillomaviridae/classificação , Infecções por Papillomavirus/veterinária , Envelhecimento , Animais , California/epidemiologia , Imuno-Histoquímica , Metagenômica/métodos , Doenças da Boca/virologia , Papillomaviridae/genética , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Filogenia
9.
Appl Environ Microbiol ; 78(24): 8762-72, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23042185

RESUMO

The risk of disease transmission from waterborne protozoa is often dependent on the origin (e.g., domestic animals versus wildlife), overall parasite load in contaminated waterways, and parasite genotype, with infections being linked to runoff or direct deposition of domestic animal and wildlife feces. Fecal samples collected from domestic animals and wildlife along the central California coast were screened to (i) compare the prevalence and associated risk factors for fecal shedding of Cryptosporidium and Giardia species parasites, (ii) evaluate the relative importance of animal host groups that contribute to pathogen loading in coastal ecosystems, and (iii) characterize zoonotic and host-specific genotypes. Overall, 6% of fecal samples tested during 2007 to 2010 were positive for Cryptosporidium oocysts and 15% were positive for Giardia cysts. Animal host group and age class were significantly associated with detection of Cryptosporidium and Giardia parasites in animal feces. Fecal loading analysis revealed that infected beef cattle potentially contribute the greatest parasite load relative to other host groups, followed by wild canids. Beef cattle, however, shed host-specific, minimally zoonotic Cryptosporidium and Giardia duodenalis genotypes, whereas wild canids shed potentially zoonotic genotypes, including G. duodenalis assemblages A and B. Given that the parasite genotypes detected in cattle were not zoonotic, the public health risk posed by protozoan parasite shedding in cattle feces may be lower than that posed by other animals, such as wild canids, that routinely shed zoonotic genotypes.


Assuntos
Criptosporidiose/veterinária , Cryptosporidium/classificação , Cryptosporidium/genética , Giardia lamblia/classificação , Giardia lamblia/genética , Giardíase/veterinária , Animais , Animais Domésticos , Animais Selvagens , California/epidemiologia , Criptosporidiose/parasitologia , Cryptosporidium/isolamento & purificação , DNA de Protozoário/química , DNA de Protozoário/genética , Fezes/parasitologia , Genótipo , Giardia lamblia/isolamento & purificação , Giardíase/parasitologia , Dados de Sequência Molecular , Prevalência , Análise de Sequência de DNA
10.
Appl Environ Microbiol ; 78(10): 3606-13, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22427504

RESUMO

Fecal pathogen contamination of watersheds worldwide is increasingly recognized, and natural wetlands may have an important role in mitigating fecal pathogen pollution flowing downstream. Given that waterborne protozoa, such as Cryptosporidium and Giardia, are transported within surface waters, this study evaluated associations between fecal protozoa and various wetland-specific and environmental risk factors. This study focused on three distinct coastal California wetlands: (i) a tidally influenced slough bordered by urban and agricultural areas, (ii) a seasonal wetland adjacent to a dairy, and (iii) a constructed wetland that receives agricultural runoff. Wetland type, seasonality, rainfall, and various water quality parameters were evaluated using longitudinal Poisson regression to model effects on concentrations of protozoa and indicator bacteria (Escherichia coli and total coliform). Among wetland types, the dairy wetland exhibited the highest protozoal and bacterial concentrations, and despite significant reductions in microbe concentrations, the wetland could still be seen to influence water quality in the downstream tidal wetland. Additionally, recent rainfall events were associated with higher protozoal and bacterial counts in wetland water samples across all wetland types. Notably, detection of E. coli concentrations greater than a 400 most probable number (MPN) per 100 ml was associated with higher Cryptosporidium oocyst and Giardia cyst concentrations. These findings show that natural wetlands draining agricultural and livestock operation runoff into human-utilized waterways should be considered potential sources of pathogens and that wetlands can be instrumental in reducing pathogen loads to downstream waters.


Assuntos
Cryptosporidium/isolamento & purificação , Enterobacteriaceae/isolamento & purificação , Giardia/isolamento & purificação , Microbiologia da Água , Água/parasitologia , Áreas Alagadas , Carga Bacteriana , California/epidemiologia , Escherichia coli , Humanos , Carga Parasitária , Estações do Ano , Tempo (Meteorologia)
11.
J Zoo Wildl Med ; 42(1): 98-104, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22946376

RESUMO

Vitamin A deficiency has rarely been reported in captive or free-ranging wildlife species. Necropsy findings in two captively housed southern sea otters (Enhydra lutris nereis) included irregular thickening of the calvaria characterized by diffuse hyperostoses on the internal surface. One animal also had moderate squamous metaplasia of the seromucinous glands of the nose. There was no measurable retinol in the liver of either sea otter. For comparison, hepatic retinol concentration was determined for 23 deceased free-ranging southern and northern (Enhydra lutris kenyoni) sea otters from California and Alaska. Free-ranging otters were found to have similar hepatic retinol concentrations (316 +/- 245 mg/kg wet weight) regardless of their location and subspecies. All of these values were significantly higher than the levels in the affected animals. Consumption of a diet with very low vitamin A concentrations and noncompliance in daily supplementation are hypothesized as the causes of vitamin A deficiency in these two sea otters.


Assuntos
Fígado/metabolismo , Lontras , Deficiência de Vitamina A/veterinária , Vitamina A/metabolismo , Criação de Animais Domésticos , Animais , Animais de Zoológico , Suplementos Nutricionais , Feminino , Fígado/química , Vitamina A/administração & dosagem , Vitamina A/química , Vitamina A/farmacologia , Deficiência de Vitamina A/metabolismo , Deficiência de Vitamina A/prevenção & controle
12.
PLoS Genet ; 6(12): e1001261, 2010 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-21203443

RESUMO

Tissue-encysting coccidia, including Toxoplasma gondii and Sarcocystis neurona, are heterogamous parasites with sexual and asexual life stages in definitive and intermediate hosts, respectively. During its sexual life stage, T. gondii reproduces either by genetic out-crossing or via clonal amplification of a single strain through self-mating. Out-crossing has been experimentally verified as a potent mechanism capable of producing offspring possessing a range of adaptive and virulence potentials. In contrast, selfing and other life history traits, such as asexual expansion of tissue-cysts by oral transmission among intermediate hosts, have been proposed to explain the genetic basis for the clonal population structure of T. gondii. In this study, we investigated the contributing roles self-mating and sexual recombination play in nature to maintain clonal population structures and produce or expand parasite clones capable of causing disease epidemics for two tissue encysting parasites. We applied high-resolution genotyping against strains isolated from a T. gondii waterborne outbreak that caused symptomatic disease in 155 immune-competent people in Brazil and a S. neurona outbreak that resulted in a mass mortality event in Southern sea otters. In both cases, a single, genetically distinct clone was found infecting outbreak-exposed individuals. Furthermore, the T. gondii outbreak clone was one of several apparently recombinant progeny recovered from the local environment. Since oocysts or sporocysts were the infectious form implicated in each outbreak, the expansion of the epidemic clone can be explained by self-mating. The results also show that out-crossing preceded selfing to produce the virulent T. gondii clone. For the tissue encysting coccidia, self-mating exists as a key adaptation potentiating the epidemic expansion and transmission of newly emerged parasite clones that can profoundly shape parasite population genetic structures or cause devastating disease outbreaks.


Assuntos
Surtos de Doenças , Interações Hospedeiro-Parasita , Sarcocystis/fisiologia , Sarcocistose/veterinária , Autofertilização , Toxoplasma/fisiologia , Toxoplasmose/parasitologia , Animais , Brasil/epidemiologia , Genótipo , Humanos , Dados de Sequência Molecular , Oocistos/crescimento & desenvolvimento , Oocistos/fisiologia , Lontras/parasitologia , Recombinação Genética , Sarcocystis/classificação , Sarcocystis/genética , Sarcocystis/crescimento & desenvolvimento , Sarcocistose/epidemiologia , Sarcocistose/parasitologia , Toxoplasma/classificação , Toxoplasma/genética , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose/epidemiologia
13.
J Med Toxicol ; 3(4): 152-6, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18072168

RESUMO

INTRODUCTION: We sought to compare antiemetic use after acetaminophen poisoning in patients treated with oral or intravenous (IV) N-acetylcysteine (NAC). METHODS: Our retrospective chart review identified 20 orally treated patients and 17 IV-treated patients. For both groups, we calculated the total number of antiemetic doses given, their associated cost, and also determined parameters that correlated with antiemetic use. RESULTS: IV-treated patients received fewer total antiemetic doses than those receiving oral NAC (1.1 0.2 vs. 2.8 0.7; P 0.04). Antiemetic cost correlated with doses received for both groups; however, because the regression lines differed (P 0.02), antiemetic therapy cost was less in IV-treated patients. In addition, serum acetaminophen concentration correlated with total antiemetic doses in oral NAC patients (P 0.002) but not with IV treatment patients (P 0.78). CONCLUSIONS: Intravenous NAC reduced antiemetic utilization, and it costs less than oral therapy. Furthermore, antiemetic use appeared to be determined by a combination of acetaminophen concentration and NAC administration route.


Assuntos
Acetaminofen/intoxicação , Acetilcisteína/administração & dosagem , Analgésicos não Narcóticos/intoxicação , Antídotos/administração & dosagem , Antieméticos/uso terapêutico , Intoxicação/tratamento farmacológico , Administração Oral , Adulto , Antieméticos/economia , Análise Custo-Benefício , Relação Dose-Resposta a Droga , Vias de Administração de Medicamentos , Quimioterapia Combinada , Feminino , Humanos , Injeções Intravenosas/economia , Masculino , Metoclopramida/uso terapêutico , Ondansetron/uso terapêutico , Estudos Retrospectivos , Resultado do Tratamento
14.
J Immunol ; 170(5): 2613-20, 2003 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-12594289

RESUMO

TGF-beta is a potent regulatory cytokine that suppresses expression of inducible NO synthase and IFN-gamma, and suppresses Th1 and Th2 cell development. We examined whether functionally active TGF-beta is present in the local environment surrounding the invading protozoan Leishmania chagasi. Our prior data showed that TGF-beta levels are significantly increased in L. chagasi-infected mice. In the current study, we found TGF-beta was also abundant in bone marrows of humans with acute visceral leishmaniasis but not in those of uninfected controls. Furthermore, L. chagasi infection caused an increase in biologically active TGF-beta in human macrophage cultures without changing the total TGF-beta. Therefore, we investigated the means through which leishmania could augment activated but not total TGF-beta. Incubation of latent TGF-beta with Leishmania sp. promastigotes caused active TGF-beta to be released from the latent complex. In contrast, the nonpathogenic protozoan Crithidia fasciculata could not activate TGF-beta. TGF-beta activation by leishmania was prevented by inhibitors of cysteine proteases and by the specific cathepsin B inhibitor CA074. Physiologic concentrations of TGF-beta inhibited killing of intracellular L. chagasi in macrophages, although the phagocytosis-induced respiratory burst remained intact. In contrast, supraphysiologic concentrations of TGF-beta had no effect on parasite survival. We hypothesize that the combined effect of abundant TGF-beta stores at extracellular sites during infection, and the ability of the parasite to activate TGF-beta in its local environment, leads to high levels of active TGF-beta in the vicinity of the infected macrophage. Locally activated TGF-beta could, in turn, enhance parasite survival through its effects on innate and adaptive immune responses.


Assuntos
Leishmania infantum/crescimento & desenvolvimento , Leishmania infantum/imunologia , Macrófagos/imunologia , Macrófagos/parasitologia , Fator de Crescimento Transformador beta/metabolismo , Animais , Células Cultivadas , Crithidia fasciculata/imunologia , Interações Hospedeiro-Parasita/imunologia , Humanos , Leishmania infantum/patogenicidade , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Macrófagos/enzimologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , NADPH Oxidases/metabolismo , Estresse Oxidativo/imunologia , Fator de Crescimento Transformador beta/fisiologia
15.
Exp Parasitol ; 100(3): 196-207, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12173405

RESUMO

Leishmania chagasi can utilize iron bound to transferrin, lactoferrin, or other chelates. We investigated the mechanism of iron uptake. Promastigotes preferentially took up iron in a reduced rather than an oxidized form, suggesting that extracellular iron must be reduced prior to internalization. Similar to literature reports, a 70-kDa protein in promastigote membrane-containing microsomes bound to [125I]-labeled transferrin. However, [125I]lactoferrin and [125I]albumin also bound a similar 70-kDa protein, suggesting that binding might not be specific. Both total and fractionated promastigotes exhibited an NADPH-dependent iron reductase activity. In contrast to trypanosomes, which take up transferrin through a specific receptor, these data support a model in which a parasite-associated or secreted reductase reduces ferric to ferrous iron, decreasing its affinity for the extracellular chelate and allowing it to be readily internalized by the parasite. This could account for the ability of the parasite to utilize iron from multiple sources in diverse host environments. Index Descriptors and Abbreviations. Index descriptors: Cryptococcus neoformans, Histoplasma capsulatum, iron, iron reductase, lactoferrin, L. chagasi, leishmaniasis, nutrient acquisition, protozoan, Saccharomyces cerevisiae, Trypanosoma brucei, Trypanosoma cruzi, transferrin; Abbreviations used: DNA, deoxyribonucleic acid; DTT, dithiothreitol; HBSS, Hanks' balanced salt solution; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NEM, N-ethylmaleimide; RNA, ribonucleic acid.


Assuntos
FMN Redutase , Ferro/metabolismo , Lactoferrina/metabolismo , Leishmania infantum/metabolismo , NADH NADPH Oxirredutases/metabolismo , Transferrina/metabolismo , Animais , Cricetinae , Radioisótopos do Iodo , Leishmania infantum/enzimologia , Leishmania infantum/crescimento & desenvolvimento , Ligantes , Mesocricetus , Proteínas de Protozoários/metabolismo
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