Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
Planta ; 257(4): 82, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36917364

RESUMO

MAIN CONCLUSION: Significantly thickened corner middle lamella of the hydroid cell wall in the stipe of dendroid moss Hypnodendron menziesii has a mechanical support function. The hydroid cell walls of the erect stipe of Hypnodendron menziesii were investigated using light microscopy (LM), transmission electron microscopy (TEM), and TEM-immunogold labeling in support of the proposed biomechanical function for the highly thickened cell corner middle lamellae. The statistical analyses of dimensions of hydroid cell and wall parameters revealed a strong positive correlation between the area of hydroid cell and (i) the hydroid cell walls adhering to thick corner middle lamella, (ii) the area of the thick cell wall at hydroid corners, and (iii) the maximum thickness of cell wall at hydroid corners. The total area of the thick cell wall at the hydroid corners concomitantly increased with the area of the hydroid cell wall adhering to the middle lamella, and with the increased number of hydroids surrounding a reference hydroid. The results suggest that markedly thickened middle lamellae of the hydroid cell wall in Hypnodendron likely function by preventing hydroid cells from collapsing under the tensile forces generated from the transpirational pull on the water column. The specific localization of (1→4)- ß-D-galactan and (1,5)-α-L-arabinan in the interface region of the hydroid cell wall and the thick middle lamella is consistent with these cell wall components being involved in the mechanical strengthening of the interface through firm adhesion as well as elasticity, ensuring the structural stability of this cell wall region, which may be prone to delamination/fracturing from the various internal and external pressures imposed. The copious presence of homogalacturonan in the thick middle lamella may further enhance the strength and flexibility of hydroid cell walls.


Assuntos
Bryopsida , Células Germinativas Vegetais , Microscopia , Galactanos/análise , Parede Celular/metabolismo
2.
Nano Lett ; 18(8): 5138-5145, 2018 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-30047268

RESUMO

The ability of proteins to form hierarchical structures through self-assembly provides an opportunity to synthesize and organize nanoparticles. Ordered nanoparticle assemblies are a subject of widespread interest due to the potential to harness their emergent functions. In this work, the toroidal-shaped form of the protein peroxiredoxin, which has a pore size of 7 nm, was used to organize iron oxyhydroxide nanoparticles. Iron in the form of Fe2+ was sequestered into the central cavity of the toroid ring using metal-binding sites engineered there and then hydrolyzed to form iron oxyhydroxide particles bound into the protein pore. By precise manipulation of the pH, the mineralized toroids were organized into stacks confining one-dimensional nanoparticle assemblies. We report the formation and the procedures leading to the formation of such nanostructures and their characterization by chromatography and microscopy. Electrostatic force microscopy clearly revealed the formation of iron-containing nanorods as a result of the self-assembly of the iron-loaded protein. This research bodes well for the use of peroxiredoxin as a template with which to form nanowires and structures for electronic and magnetic applications.


Assuntos
Nanopartículas/química , Peroxirredoxinas/química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Ferro/química , Nanotecnologia , Tamanho da Partícula , Porosidade , Ligação Proteica , Multimerização Proteica , Eletricidade Estática
3.
Biol Reprod ; 96(1): 159-173, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28395327

RESUMO

The mammalian epididymis is an exceptionally long ductal system tasked with the provision of one of the most complex intraluminal fluids found in any exocrine gland. This specialized milieu is continuously modified by the combined secretory and absorptive of the surrounding epithelium and thus finely tuned for its essential roles in promoting sperm maturation and storage. While considerable effort has been focused on defining the composition of the epididymal fluid, relatively less is known about the intracellular trafficking machinery that regulates this luminal environment. Here, we characterize the ontogeny of expression of a master regulator of this machinery, the dynamin family of mechanoenzymes. Our data show that canonical dynamin isoforms were abundantly expressed in the juvenile mouse epididymis. However, in peripubertal and adult animals dynamin takes on a heterogeneous pattern of expression such that the different isoforms displayed both cell- and segment-specific localization. Thus, dynamin 1 and 3 were predominately localized in the distal epididymal segments (corpus and cauda), where they were found within clear and principal cells, respectively. In contrast, dynamin 2 was expressed throughout the epididymis, but localized to the Golgi apparatus of the principal cells in the proximal (caput) segment and the luminal border of these cells in more distal segments. These dynamin isoforms are therefore ideally positioned to play complementary, nonredundant roles in the regulation of the epididymal milieu. In support of this hypothesis, selective inhibition of dynamin altered the profile of proteins secreted from an immortalized caput epididymal cell line.


Assuntos
Dinaminas/metabolismo , Epididimo/metabolismo , Animais , Epididimo/crescimento & desenvolvimento , Masculino , Camundongos , ATPases Vacuolares Próton-Translocadoras/metabolismo
4.
Mol Hum Reprod ; 23(10): 657-673, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29044420

RESUMO

STUDY QUESTION: Does dynamin regulate human sperm acrosomal exocytosis? SUMMARY ANSWER: Our studies of dynamin localization and function have implicated this family of mechanoenzymes in the regulation of progesterone-induced acrosomal exocytosis in human spermatozoa. WHAT IS KNOWN ALREADY: Completion of an acrosome reaction is a prerequisite for successful fertilization in all studied mammalian species. It follows that failure to complete this unique exocytotic event represents a common aetiology in the defective spermatozoa of male infertility patients that have failed IVF in a clinical setting. Recent studies have implicated the dynamin family of mechanoenzymes as important regulators of the acrosome reaction in murine spermatozoa. The biological basis of this activity appears to rest with the ability of dynamin to polymerize around newly formed membrane vesicles and subsequently regulate the rate of fusion pore expansion. To date, however, the dynamin family of GTPases have not been studied in the spermatozoa of non-rodent species. Here, we have sought to examine the presence and functional significance of dynamin in human spermatozoa. STUDY DESIGN, SIZE, DURATION: Dynamin expression was characterized in the testis and spermatozoa of several healthy normozoospermic individuals. In addition, we assessed the influence of selective dynamin inhibition on the competence of human spermatozoa to undergo a progesterone-induced acrosome reaction. A minimum of five biological and technical replicates were performed to investigate both inter- and intra-donor variability in dynamin expression and establish statistical significance in terms of the impact of dynamin inhibition. PARTICIPANTS/MATERIALS, SETTING, METHODS: The expression and the localization of dynamin in the human testis, epididymis and mature spermatozoa were determined through the application of immunofluorescence, immunoblotting and/or electron microscopy. Human semen samples were fractionated via density gradient centrifugation and the resultant populations of good and poor quality spermatozoa were induced to capacitate and acrosome react in the presence or absence of selective dynamin inhibitors. The acrosome integrity of live spermatozoa was subsequently assessed via the use of fluorescently conjugated Arachis hypogea lectin (PNA). The influence of dynamin phosphorylation and the regulatory kinase(s) responsible for this modification in human spermatozoa were also assessed via the use of in situ proximity ligation assays and pharmacological inhibition. In all experiments, ≥100 spermatozoa were assessed/treatment group and all graphical data are presented as the mean values ± SEM, with statistical significance being determined by ANOVA. MAIN RESULTS AND THE ROLE OF CHANCE: Dynamin 1 (DNM1) and DNM2, but not DNM3, were specifically localized to the acrosomal region of the head of human spermatozoa, an ideal position from which to regulate acrosomal exocytosis. In keeping with this notion, pharmacological inhibition of DNM1 and DNM2 was able to significantly suppress the rates of acrosomal exocytosis stimulated by progesterone. Furthermore, our comparison of dynamin expression in good and poor quality spermatozoa recovered from the same ejaculate, revealed a significant reduction in the amount of DNM2 in the latter subpopulation of cells. In contrast, DNM1 was detected at equivalent levels in both subpopulations of spermatozoa. Such findings are of potential significance given that the poor quality spermatozoa proved refractory to the induction of a progesterone stimulated acrosome reaction. In seeking to identify the regulatory influence of progesterone on DNM2 function, we were able to establish that the protein is a substrate for CDK1-dependent phosphorylation. The functional significance of DNM2 phosphorylation was illustrated by the fact that pharmacological inhibition of CDK1 elicited a concomitant suppression of both DNM2-Ser764 phosphorylation and the overall rates of progesterone-induced acrosomal exocytosis. LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: This was an in vitro study performed mainly on ejaculated human spermatozoa. This experimental paradigm necessarily eliminates the physiological contributions of the female reproductive tract that would normally support capacitation and acrosomal responsiveness. WIDER IMPLICATIONS OF THE FINDINGS: This study identifies a novel causative link between dynamin activity and the ability of human spermatozoa to complete a progesterone-induced acrosome reaction. Such findings encourage a more detailed analysis of the contribution of dynamin dysregulation as an underlying aetiology in infertile males whose spermatozoa are unable to penetrate the zona pellucida. STUDY FUNDING/COMPETING INTEREST(S): This research was supported by a National Health and Medical Research Council of Australia Project Grant (APP1103176) awarded to B.N. and E.A.M. The authors report no conflict of interest.


Assuntos
Reação Acrossômica/efeitos dos fármacos , Proteína Quinase CDC2/genética , Dinamina I/genética , Dinaminas/genética , Progesterona/farmacologia , Espermatozoides/efeitos dos fármacos , Reação Acrossômica/fisiologia , Animais , Encéfalo/metabolismo , Proteína Quinase CDC2/metabolismo , Dinamina I/antagonistas & inibidores , Dinamina I/metabolismo , Dinamina II , Dinaminas/antagonistas & inibidores , Dinaminas/metabolismo , Epididimo/citologia , Epididimo/metabolismo , Exocitose/efeitos dos fármacos , Regulação da Expressão Gênica , Humanos , Hidrazonas/farmacologia , Masculino , Mecanotransdução Celular , Camundongos , Naftóis/farmacologia , Fosforilação/efeitos dos fármacos , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Espermatozoides/metabolismo , Espermatozoides/ultraestrutura , Testículo/citologia , Testículo/metabolismo
5.
Proc Natl Acad Sci U S A ; 109(21): 8328-33, 2012 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-22566625

RESUMO

The circadian clock is an autonomous oscillator that produces endogenous biological rhythms with a period of about 24 h. This clock allows organisms to coordinate their metabolism and development with predicted daily and seasonal changes of the environment. In plants, circadian rhythms contribute to both evolutionary fitness and agricultural productivity. Nevertheless, we show that commercial barley varieties bred for short growing seasons by use of early maturity 8 (eam8) mutations, also termed mat-a, are severely compromised in clock gene expression and clock outputs. We identified EAM8 as a barley ortholog of the Arabidopsis thaliana circadian clock regulator EARLY FLOWERING3 (ELF3) and demonstrate that eam8 accelerates the transition from vegetative to reproductive growth and inflorescence development. We propose that eam8 was selected as barley cultivation moved to high-latitude short-season environments in Europe because it allowed rapid flowering in genetic backgrounds that contained a previously selected late-flowering mutation of the photoperiod response gene Ppd-H1. We show that eam8 mutants have increased expression of the floral activator HvFT1, which is independent of allelic variation at Ppd-H1. The selection of independent eam8 mutations shows that this strategy facilitates short growth-season adaptation and expansion of the geographic range of barley, despite the pronounced clock defect.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Ritmo Circadiano/genética , Hordeum/crescimento & desenvolvimento , Hordeum/genética , Estações do Ano , Adaptação Fisiológica/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Ligação à Clorofila/genética , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Flores/fisiologia , Regulação da Expressão Gênica de Plantas , Hordeum/fisiologia , Dados de Sequência Molecular , Mutagênese/fisiologia , Fenótipo , Fotoperíodo , Fatores de Transcrição/genética
6.
Plant J ; 74(6): 989-1002, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23551421

RESUMO

Glaucousness is described as the scattering effect of visible light from wax deposited on the cuticle of plant aerial organs. In wheat, two dominant genes lead to non-glaucous phenotypes: Inhibitor of wax 1 (Iw1) and Iw2. The molecular mechanisms and the exact extent (beyond visual assessment) by which these genes affect the composition and quantity of cuticular wax is unclear. To describe the Iw1 locus we used a genetic approach with detailed biochemical characterization of wax compounds. Using synteny and a large number of F2 gametes, Iw1 was fine-mapped to a sub-cM genetic interval on wheat chromosome arm 2BS, which includes a single collinear gene from the corresponding Brachypodium and rice physical maps. The major components of flag leaf and peduncle cuticular waxes included primary alcohols, ß-diketones and n-alkanes. Small amounts of C19-C27 alkyl and methylalkylresorcinols that have not previously been described in wheat waxes were identified. Using six pairs of BC2 F3 near-isogenic lines, we show that Iw1 inhibits the formation of ß- and hydroxy-ß-diketones in the peduncle and flag leaf blade cuticles. This inhibitory effect is independent of genetic background or tissue, and is accompanied by minor but consistent increases in n-alkanes and C24 primary alcohols. No differences were found in cuticle thickness and carbon isotope discrimination in near-isogenic lines differing at Iw1.


Assuntos
Cromossomos de Plantas/genética , Regulação da Expressão Gênica de Plantas , Cetonas/química , Proteínas de Plantas/genética , Triticum/genética , Álcoois/química , Álcoois/isolamento & purificação , Alcanos/química , Alcanos/isolamento & purificação , Alelos , Brachypodium/genética , Mapeamento Cromossômico , Cromatografia Gasosa-Espectrometria de Massas , Hordeum/genética , Cetonas/isolamento & purificação , Lipídeos/química , Lipídeos/isolamento & purificação , Oryza/genética , Fenótipo , Epiderme Vegetal/química , Epiderme Vegetal/genética , Epiderme Vegetal/metabolismo , Epiderme Vegetal/ultraestrutura , Folhas de Planta/química , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Proteínas de Plantas/metabolismo , Triticum/química , Triticum/metabolismo , Triticum/ultraestrutura , Ceras/química , Ceras/isolamento & purificação
7.
Mol Microbiol ; 89(4): 702-14, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23796263

RESUMO

The Serratia entomophila antifeeding prophage Afp, forms a phage-tail-like particle that acts on the New Zealand grass grub, Costelytra zealandica with a 3-day LD50 of approximately 500 Afp particles per larva. Genes (afp1-18) encoding components of Afp were expressed and their products purified allowing morphological assessment of the products by transmission electron microscopy (TEM). Expression of afp1-15 resulted in the formation of a non-sheathed structure termed the tube-baseplate complex or TBC, composed of an irregular-length tube attached to a baseplate with associated tail fibres. Expression of afp1-16 produced mature, normal-length Afp particles, whereas coexpression of afp16 with afp1-15 in trans resulted in the formation of aberrant Afp particles of variable lengths. A C-terminally truncated Afp16 mutant resulted in a phenotype intermediate between mature Afp and TBC. The addition of purified Afp16 to Afp unravelled by acidic treatment resulted in the formation of shorter tubes when specimen pH was adjusted to 7 than those formed in the absence of Afp16. Analysis of TEM images of purified Afp16 revealed a hexameric ring-like structure similar to that formed by gp3 of phage T4 and gpU of phage λ. Our results suggest that Afp16 terminates tube elongation and is involved in sheath formation.


Assuntos
Prófagos/genética , Prófagos/metabolismo , Serratia/virologia , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vírion/ultraestrutura , Análise Mutacional de DNA , Teste de Complementação Genética , Microscopia Eletrônica de Transmissão , Deleção de Sequência , Vírion/genética
8.
BMC Plant Biol ; 14: 191, 2014 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-25034643

RESUMO

BACKGROUND: Grain yield in wheat is a polygenic trait that is influenced by environmental and genetic interactions at all stages of the plant's growth. Yield is usually broken down into three components; number of spikes per area, grain number per spike, and grain weight (TGW). In polyploid wheat, studies have identified quantitative trait loci (QTL) which affect TGW, yet few have been validated and fine-mapped using independent germplasm, thereby having limited impact in breeding. RESULTS: In this study we identified a major QTL for TGW, yield and green canopy duration on wheat chromosome 6A of the Spark x Rialto population, across 12 North European environments. Using independent germplasm in the form of BC2 and BC4 near isogenic lines (NILs), we validated the three QTL effects across environments. In four of the five experiments the Rialto 6A introgression gave significant improvements in yield (5.5%) and TGW (5.1%), with morphometric measurements showing that the increased grain weight was a result of wider grains. The extended green canopy duration associated with the high yielding/TGW Rialto allele was comprised of two independent effects; earlier flowering and delayed final maturity, and was expressed stably across the five environments. The wheat homologue (TaGW2) of a rice gene associated with increased TGW and grain width was mapped within the QTL interval. However, no polymorphisms were identified in the coding sequence between the parents. CONCLUSION: The discovery and validation through near-isogenic lines of robust QTL which affect yield, green canopy duration, thousand grain weight, and grain width on chromosome 6A of hexaploid wheat provide an important first step to advance our understanding of the genetic mechanisms regulating the complex processes governing grain size and yield in polyploid wheat.


Assuntos
Biomassa , Cromossomos de Plantas , Locos de Características Quantitativas , Triticum/genética , Mapeamento Cromossômico , Interação Gene-Ambiente , Poliploidia , Análise de Sequência de DNA , Triticum/crescimento & desenvolvimento
9.
Plant J ; 71(1): 71-84, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22372488

RESUMO

Flowering time is a trait that has been extensively altered during wheat domestication, enabling it to be highly productive in diverse environments and providing a rich source of variation for studying adaptation mechanisms. Hexaploid wheat is ancestrally a long-day plant, but many environments require varieties with photoperiod insensitivity (PI) that can flower in short days. PI results from mutations in the Ppd-1 gene on the A, B or D genomes, with individual mutations conferring different degrees of earliness. The basis of this is poorly understood. Using a common genetic background, the effects of A, B and D genome PI mutations on genes of the circadian clock and photoperiod pathway were studied using genome-specific expression assays. Ppd-1 PI mutations did not affect the clock or immediate clock outputs, but affected TaCO1 and TaFT1, with a reduction in TaCO1 expression as TaFT1 expression increased. Therefore, although Ppd-1 is related to PRR genes of the Arabidopsis circadian clock, Ppd-1 affects flowering by an alternative route, most likely by upregulating TaFT1 with a feedback effect that reduces TaCO1 expression. Individual genes in the circadian clock and photoperiod pathway were predominantly expressed from one genome, and there was no genome specificity in Ppd-1 action. Lines combining PI mutations on two or three genomes had enhanced earliness with higher levels, but not earlier induction, of TaFT1, showing that there is a direct quantitative relationship between Ppd-1 mutations, TaFT1 expression and flowering.


Assuntos
Flores/fisiologia , Genoma de Planta , Mutação , Fotoperíodo , Triticum/genética , Relógios Circadianos , Cruzamentos Genéticos , Flores/genética , Regulação da Expressão Gênica de Plantas , Poliploidia , Triticum/fisiologia
10.
Theor Appl Genet ; 126(9): 2267-77, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23737074

RESUMO

Vernalization-2 (Vrn-2) is the major flowering repressor in temperate cereals. It is only expressed under long days in wild-type plants. We used two day-neutral (photoperiod insensitive) mutations that allow rapid flowering in short or long days to investigate the day length control of Vrn-2. The barley (Hordeum vulgare) early maturity8 (eam8) mutation affects the barley ELF3 gene. eam8 mutants disrupt the circadian clock resulting in elevated expression of Ppd-H1 and the floral activator HvFT1 under short or long days. When eam8 was crossed into a genetic background with a vernalization requirement Vrn-2 was expressed under all photoperiods and the early flowering phenotype was partially repressed in unvernalized (UV) plants, likely due to competition between the constitutively active photoperiod pathway and the repressing effect of Vrn-2. We also investigated the wheat (Triticum aestivum) Ppd-D1a mutation. This differs from eam8 in causing elevated levels of Ppd-1 and TaFT1 expression without affecting the circadian clock. We used genotypes that differed in "short-day vernalization". Short days were effective in promoting flowering in individuals wild type at Ppd-D1, but not in individuals that carry the Ppd-D1a mutation. The latter showed Vrn-2 expression in short days. In summary, eam8 and Ppd-D1a mimic long days in terms of photoperiod response, causing Vrn-2 to become aberrantly expressed (in short days). As Ppd-D1a does not affect the circadian clock, this also shows that clock regulation of Vrn-2 operates indirectly through one or more downstream genes, one of which may be Ppd-1.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Hordeum/genética , Fotoperíodo , Proteínas de Plantas/genética , Triticum/genética , Alelos , Relógios Circadianos , Cruzamentos Genéticos , Flores/genética , Flores/metabolismo , Genótipo , Mutação , Fenótipo , Proteínas de Plantas/metabolismo , Estações do Ano
11.
J Med Econ ; 26(1): 902-914, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37417781

RESUMO

AIMS: To assess the cost-effectiveness of tezepelumab as add-on maintenance therapy compared with standard of care (SoC) for the treatment of patients with severe asthma in Canada. MATERIAL AND METHODS: A cost utility analysis was conducted using a Markov cohort model with five health states ("controlled asthma", "uncontrolled asthma", "previously controlled asthma with exacerbation", "previously uncontrolled asthma with exacerbation", and "death"). Tezepelumab plus SoC was compared to SoC (high-dose inhaled corticosteroids plus long-acting beta agonist) using efficacy estimates derived from the NAVIGATOR (NCT03347279) and SOURCE (NCT03406078) trials. The model included the costs of therapy, administration, resource use for disease management, and adverse events. Utility estimates were calculated using a mixed-effects regression analysis of the NAVIGATOR and SOURCE trials. A Canadian public payer perspective was used with a 50-year time horizon, a 1.5% annual discount rate, and the base case analysis was conducted probabilistically. A key scenario analysis assessed the cost-effectiveness of tezepelumab compared with currently reimbursed biologics informed by an indirect treatment comparison. RESULTS: The base case analysis suggested that tezepelumab plus SoC was associated with a quality-adjusted life-year (QALY) gain of 1.077 compared with SoC alone at an incremental cost of $207,101 (2022 Canadian dollars), resulting in an incremental cost-utility ratio of $192,357/QALY. The key scenario analysis demonstrated that tezepelumab was dominant against all currently reimbursed biologics, with higher incremental QALYs (ranging from 0.062 to 0.407) and lower incremental costs (ranging from -$6,878 to -$1,974). Additionally, when compared against currently reimbursed biologics in Canada, tezepelumab had the highest probability of being cost-effective across all willingness-to-pay (WTP) thresholds. CONCLUSION: Tezepelumab provided additional life years and QALYs at additional cost compared with SoC in Canada. In addition, tezepelumab dominated (i.e. more effective, less costly) the other currently reimbursed biologics.


Assuntos
Asma , Produtos Biológicos , Humanos , Análise Custo-Benefício , Canadá , Asma/tratamento farmacológico , Produtos Biológicos/uso terapêutico , Anos de Vida Ajustados por Qualidade de Vida
12.
J Orthop ; 21: 438-443, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32968338

RESUMO

INTRODUCTION: The recognition of anteromedial knee arthritis as a distinct early clinicopathological entity has led to a resurgence in medial unicompartment knee arthroplasty (UKA). Symptomatic knee pain caused by 180° rotational spin of the mobile bearing of the Oxford Knee is an unrecognized and therefore under-reported complication of UKA. Whilst the post-operative radiographic criteria for optimal positioning of UKA is well described in the available literature, this isn't the case for assessing antero-posterior (AP) orientation of the mobile-bearing. METHODS: Following a literature review, we describe a novel radiographic technique that can consistently assess AP orientation, and as a result, diagnose 180° rotational spin of the mobile-bearing. This technique overcomes the radiological challenge of superimposition of the radiopaque markers with the lateral edge of the tibial tray. RESULTS: The modified oblique view results in clear visualization of the metallic rod embedded in the polyethylene, away from the lateral edge of the tibial tray. An anteriorly viewed metallic rod would indicate a well oriented mobile bearing. However, if the metallic beads are visualized anteriorly without dislocation, the component would have spun 180°. CONCLUSION: Clinicians should have a high index of suspicion for 180° spin to have occurred in patients with posterior dislocation with or without spontaneous reduction. We recommend bearing exchange ± revision arthroplasty for symptomatic patients. The modified oblique view is now part of our immediate post-operative XR protocol and repeated for any patient who re-presents symptomatically at any stage following the index procedure.

13.
Pediatr Neurol ; 104: 46-53, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31902550

RESUMO

BACKGROUND: Ketamine has recently emerged as a promising therapeutic alternative for abortive migraine therapy, likely secondary to N-methyl-d-aspartate antagonism. Most reports examine adults and the intravenous route. Fewer utilize intranasal administration or pediatric populations. Given the limited evidence for intranasal ketamine in pediatric migraine populations, we retrospectively reviewed our experience to further characterize safety and efficacy of intranasal ketamine in this population. METHODS: A retrospective review in a free-standing, pediatric medical center was performed examining the utilization of intranasal ketamine at 0.1 to 0.2 mg/kg/dose up to five doses in pediatric migraineurs. Pain scores (scale = 0 to 10) were recorded at baseline and after each dose. Response was characterized as pain score reduction to 0 to -3 and/or reduction of at least 50%. RESULTS: Twenty-five encounters (25 of 34; 73.5%) were responders (mean pain score reduction of -7.2 from admission to treatment completion). Overall pain reduction from admission to discharge in the entire study population was 66.1%. Side effects were mild and transient. CONCLUSIONS: Our experience with intranasal ketamine has promising outcomes in both pain relief and side effect minimization. When other therapeutic options are unavailable, practitioners should consider intranasal ketamine.


Assuntos
Antagonistas de Aminoácidos Excitatórios/farmacologia , Ketamina/farmacologia , Transtornos de Enxaqueca/tratamento farmacológico , Avaliação de Resultados em Cuidados de Saúde , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Administração Intranasal , Adolescente , Criança , Antagonistas de Aminoácidos Excitatórios/administração & dosagem , Feminino , Humanos , Ketamina/administração & dosagem , Masculino , Medição da Dor , Estudos Retrospectivos
14.
Ultrason Sonochem ; 51: 325-331, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30322767

RESUMO

The vegetative cells and spores of Geobacillus spp. and Anoxybacillus flavithermus were subjected to 20 kHz ultrasound with a power ∼8 W. Ultrasonication had considerable effect on vegetative cells (5-log reduction in Geobacillus spp. and 1.6-log reduction in A.flavithermus). TEM imaging of the ultrasonicated vegetative cells showed an extensive damage both internally and externally. However, spores showed high resistance towards ultrasound treatment in the absence of NaOH and H2O2, although the outer layers such as the exosporium and the outer coat layer were disrupted, resulting in the reduced resistance of spores towards sonication. The combination of 0.12 M NaOH and 10 min ultrasonication inactivated 6 log spores of Geobacillus spp. A 7 log spore reduction of A.flavithermus was achieved by combining 0.17 M NaOH with 10 min ultrasonication. Ultrasonication combined with 1% H2O2 inactivated ∼7 log Geobacillus spp. spores in 6 min and ∼7 log A.flavithermus spores in 3 min. These ultrasound treatments in the presence of NaOH and H2O2 are synergistic as they showed a greater spore reduction when compared to NaOH combined with high temperature (85 °C), where only 1 and 3 log reduction was achieved in Geobacillus spp. and A.flavithermus spores, respectively.


Assuntos
Anoxybacillus/fisiologia , Geobacillus/fisiologia , Peróxido de Hidrogênio/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Hidróxido de Sódio/farmacologia , Ondas Ultrassônicas , Anoxybacillus/efeitos dos fármacos , Geobacillus/efeitos dos fármacos , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/fisiologia
15.
J Med Econ ; 22(11): 1210-1220, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31456454

RESUMO

Objectives: The aim of this literature review was to provide a comprehensive report on hospital costs, and cost components, for a range of ventral cavity surgical procedures across three regions of focus: (1) Americas, (2) Europe, Middle East and Africa (EMEA), and (3) Asia-Pacific. Methods: A structured search was performed and utilized a combination of controlled vocabulary (e.g., "Hepatectomy", "Colectomy", "Costs and Cost Analysis") and keywords (e.g. "liver resection", "bowel removal", "economics"). Studies were considered eligible for inclusion if they reported hospital-related costs associated with the procedures of interest. Cost outcomes included operating room (OR) time costs, total OR costs, ward stay costs, total admission costs, OR cost per minute and ward cost per day. All costs were converted to 2018 USD. Results: Total admission costs were observed to be highest in the Americas, with an average cost of $15,791. The average OR time cost per minute was found to vary by region: $24.83 (Americas), $14.29 (Asia-Pacific), and $13.90 (EMEA). A cost-breakdown demonstrated that OR costs typically comprised close to 50%, or more, of hospital admission costs. This review also demonstrates that decreasing OR time by 30 min provides cost savings approximately equivalent to a 1-day reduction in ward time. Conclusion: This literature review provided a comprehensive assessment of hospital costs across various surgical procedures, approaches, and geographical regions. Our findings indicate that novel processes and healthcare technologies that aim to reduce resources such as operating time and hospital stay, can potentially provide resource savings for hospital payers.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório/economia , Custos Hospitalares/estatística & dados numéricos , Hospitalização/economia , Saúde Global , Hospitalização/estatística & dados numéricos , Humanos , Tempo de Internação/economia , Duração da Cirurgia
16.
Artigo em Inglês | MEDLINE | ID: mdl-30637118

RESUMO

OBJECTIVES: Anecdotally, several strategies have been suggested in order to improve tolerability of fish oil supplements, but there is little evidence supporting any of these strategies. The aim of this study was to determine if there is a difference among four methods of oral administration of fish oil supplementation in terms of tolerability and adherence. METHODS: A randomized, prospective, open-label, four-arm pilot study was conducted on 60 healthy adult subjects randomized to different fish oil supplement administration methods with (1) milk, (2) food, (3) an empty stomach, and (4) frozen capsules prior to ingestion. Each subject was instructed to take two capsules three times daily for 30 consecutive days. Adherence was assessed by pill counts. Adverse effects were assessed by survey and patient exit interview. RESULTS: No apparent differences were demonstrated among the four administration groups in terms of adherence, reasons for non-adherence, or self-reported adverse effects. CONCLUSIONS: Method of administration did not affect rates of adherence or incidence of adverse effects in a small cohort of healthy adults taking fish oil supplement capsules for 30 days. TRIAL REGISTRATION: ClinicalTrials.gov NCT01471366. Registered November 16, 2011.

17.
Genetics ; 176(1): 599-609, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17339225

RESUMO

The FLOWERING LOCUS T (FT) gene plays a central role in integrating flowering signals in Arabidopsis because its expression is regulated antagonistically by the photoperiod and vernalization pathways. FT belongs to a family of six genes characterized by a phosphatidylethanolamine-binding protein (PEBP) domain. In rice (Oryza sativa), 19 PEBP genes were previously described, 13 of which are FT-like genes. Five FT-like genes were found in barley (Hordeum vulgare). HvFT1, HvFT2, HvFT3, and HvFT4 were highly homologous to OsFTL2 (the Hd3a QTL), OsFTL1, OsFTL10, and OsFTL12, respectively, and this relationship was supported by comparative mapping. No rice equivalent was found for HvFT5. HvFT1 was highly expressed under long-day (inductive) conditions at the time of the morphological switch of the shoot apex from vegetative to reproductive growth. HvFT2 and HvFT4 were expressed later in development. HvFT1 was therefore identified as the main barley FT-like gene involved in the switch to flowering. Mapping of HvFT genes suggests that they provide important sources of flowering-time variation in barley. HvFTI was a candidate for VRN-H3, a dominant mutation giving precocious flowering, while HvFT3 was a candidate for Ppd-H2, a major QTL affecting flowering time in short days.


Assuntos
Genes de Plantas , Hordeum/genética , Sequência de Aminoácidos , Arabidopsis/genética , Cromossomos Artificiais Bacterianos/genética , Bases de Dados Genéticas , Éxons/genética , Flores/genética , Flores/fisiologia , Perfilação da Expressão Gênica , Íntrons/genética , Dados de Sequência Molecular , Oryza/genética , Fotoperíodo , Filogenia , Mapeamento Físico do Cromossomo , Proteínas de Plantas/química , Proteínas de Plantas/genética , Estrutura Terciária de Proteína , Locos de Características Quantitativas/genética , Fatores de Tempo
18.
Seizure ; 50: 173-185, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28704741

RESUMO

PURPOSE: Review and discuss medications efficacious for seizure control, despite primary indications for other diseases, as treatment options in patients who have failed therapy with traditional antiepileptic drugs (AEDs). METHODS: Literature searches were conducted utilizing PubMed and MEDLINE databases employing combinations of search terms including, but not limited to, "epilepsy", "refractory", "seizure", and the following medications: acetazolamide, amantadine, bumetanide, imipramine, lidocaine, verapamil, and various stimulants. RESULTS: Data from relevant case studies, retrospective reviews, and available clinical trials were gathered, analyzed, and reported. Experience with acetazolamide, amantadine, bumetanide, imipramine, lidocaine, verapamil, and various stimulants show promise for cases of refractory epilepsy in both adults and children. Many medications lack large scale, randomized clinical trials, but the available data is informative when choosing treatment for patients that have failed traditional epilepsy therapies. CONCLUSIONS: All neurologists have encountered a patient that failed nearly every AED, diet, and surgical option. For these patients, we often seek fortuitous discoveries within small series and case reports, hoping to find a treatment that might help the patient. In the present review, we describe medications for which antiepileptic effect has been ascribed after they were introduced for other indications.


Assuntos
Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Amantadina/uso terapêutico , Bumetanida/uso terapêutico , Estimulantes do Sistema Nervoso Central/uso terapêutico , Humanos , Imipramina/uso terapêutico , Lidocaína/uso terapêutico , Falha de Tratamento , Verapamil/uso terapêutico
19.
Am J Clin Nutr ; 80(6): 1645-9, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15585781

RESUMO

BACKGROUND: Vitamin D is made in the skin on exposure to solar radiation, and it is necessary to optimal skeletal health. Subjects who use a tanning bed that emits ultraviolet B radiation (290-315 nm) are likely to have higher 25-hydroxyvitamin D [25(OH)D] concentrations than do subjects who do not regularly use a tanning bed. OBJECTIVE: The first objective of this study was to ascertain whether subjects who regularly use a tanning bed have higher 25(OH)D concentrations than do subjects who do not use a tanning bed. The second objective was to ascertain whether higher 25(OH)D concentrations correlated positively with bone mineral density. DESIGN: This cross-sectional analysis examined 50 subjects who used a tanning bed at least once a week and 106 control subjects. Each subject gave a blood specimen for measurement of serum 25(OH)D and parathyroid hormone concentrations. Each subject underwent bone mineral density testing of the hip and spine. RESULTS: Subjects who used a tanning bed had serum 25(OH)D concentrations 90% higher than those of control subjects (115.5 +/- 8.0 and 60.3 +/- 3.0 nmol/L, respectively; P <0.001). Subjects who used a tanning bed had parathyroid hormone concentrations 18% lower than those of control subjects (21.4 +/- 1.0 and 25.3 +/- 0.8 pg/mL, respectively; P=0.01). Tanners had significantly higher BMD and z scores at the total hip than did nontanners. CONCLUSION: The regular use of a tanning bed that emits vitamin D-producing ultraviolet radiation is associated with higher 25(OH)D concentrations and thus may have a benefit for the skeleton.


Assuntos
Densidade Óssea/fisiologia , Osso e Ossos/efeitos da radiação , Raios Ultravioleta , Vitamina D/análogos & derivados , Vitamina D/sangue , Vitamina D/efeitos da radiação , Absorciometria de Fóton , Adulto , Idoso , Densidade Óssea/efeitos da radiação , Osso e Ossos/metabolismo , Estudos de Casos e Controles , Estudos Transversais , Feminino , Quadril/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Hormônio Paratireóideo/sangue , Estações do Ano , Coluna Vertebral/diagnóstico por imagem , Luz Solar , Estados Unidos , Vitamina D/metabolismo , Deficiência de Vitamina D/epidemiologia
20.
J Clin Densitom ; 5(1): 57-62, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-11940729

RESUMO

It is widely accepted that bone mineral density (BMD) measurements obtained by dual-energy X-ray absorptiometry (DXA) at the spine, hip, and calcaneus predict fracture risk. Few published studies to date have examined the relationship between pDXA measurements at the calcaneus to those at the hip and spine. It has been demonstrated that T-score-based criteria cannot be universally applied to all skeletal sites and measurement technologies. Our goal was to define the calcaneal T-score threshold equivalent to low bone mass at the hip or spine. A total of 119 female patients between the ages of 33 and 76 yr of age were recruited at Boston University Medical Center for bone densitometry screening. Bone density measurements were obtained at the calcaneus using the portable Norland Apollo Densitometer (Norland Medical Systems, Fort Atkinson, WI) and at the hip and spine using the Norland Eclipse densitometer. By defining a pDXA T-score < or =-1 as a positive test and DXA scores < or =-1 as the presence of low bone mass, we obtained a specificity of 100% and a sensitivity of 73% (positive predictive value 100% and negative predictive value 80%) in detecting low bone mass at the femoral neck in women over age 65 yr. In women between 40 and 65 yr of age, we obtained a sensitivity of 50% and a specificity of 93% (positive predictive value 93% and negative predictive value 50%) in detecting low bone mass at the femoral neck. In women less than 40 yr of age, we obtained a sensitivity of 13% and a specificity of 100% (positive predictive value 100% and negative predictive value 75%) in detecting low bone mass at the femoral neck. From receiver operating characteristic curves, a calcaneal T-score < or =0.0 detects those with a T-score < or =-1 at the femoral neck and lumbar spine with 100% and 85% sensitivity, respectively. Peripheral DXA of the calcaneus is a sensitive and specific test to diagnose low bone mass in women over 65 yr of age. In women under 65 yr of age, this modality, though not as sensitive, is specific in detecting low bone mass. We conclude that a pDXA calcaneal T-score < or =0 is highly sensitive in predicting osteopenia and osteoporosis at the femoral neck and lumbar spine.


Assuntos
Densidade Óssea , Calcâneo/fisiologia , Ossos Pélvicos/fisiologia , Coluna Vertebral/fisiologia , Absorciometria de Fóton , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Curva ROC , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA