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1.
Osteoporos Int ; 33(8): 1703-1714, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35524068

RESUMO

Real-world evidence on the comparative effectiveness and safety of abaloparatide versus teriparatide in women with osteoporosis may help inform treatment decisions. Following 18 months of treatment, abaloparatide was comparable to teriparatide for prevention of nonvertebral fractures, resulted in a 22% risk reduction for hip fractures, and demonstrated similar cardiovascular safety. Osteoporotic fracture risk can be reduced with anabolic or antiresorptive medications. In addition to efficacy and safety data from controlled clinical trials, real-world evidence on comparative effectiveness and safety may help inform treatment decisions. INTRODUCTION: The real-world effectiveness of abaloparatide versus teriparatide on nonvertebral fracture (NVF) incidence and cardiovascular safety during the 19-month period after treatment initiation were evaluated (NCT04974723). METHODS: Anonymized US patient claims data from Symphony Health, Integrated Dataverse (IDV)®, May 1, 2017 to July 31, 2019, included women aged ≥ 50 years with ≥ 1 prescription of abaloparatide or teriparatide and no prior anabolic therapy. Most were enrolled in commercial and Medicare health plans. Index was the date of the initial prescription dispensed during the identification period. In 1:1 propensity score matched cohorts, time to first NVF following index date, major adverse cardiovascular events (MACE), and MACE + heart failure (HF) were compared between cohorts using a Cox proportional hazards model. RESULTS: Propensity score matching yielded 11,616 patients per cohort. Overall median age (interquartile range) was 67 (61, 75) years, and 25.6% had a fracture history. Over 19 months, 335 patients on abaloparatide and 375 on teriparatide had a NVF (hazard ratio [95% confidence interval]: 0.89 [0.77, 1.03]), and 121 and 154 patients, respectively, had a hip fracture [HR (95% CI): 0.78 (0.62, 1.00)]. The MACE and MACE + HF rates were similar between cohorts. CONCLUSIONS: Following 18 months of treatment, abaloparatide was comparable to teriparatide for prevention of NVF and similar cardiovascular safety was demonstrated between cohorts.


Assuntos
Conservadores da Densidade Óssea , Fraturas do Quadril , Osteoporose Pós-Menopausa , Fraturas por Osteoporose , Idoso , Conservadores da Densidade Óssea/efeitos adversos , Feminino , Fraturas do Quadril/complicações , Fraturas do Quadril/epidemiologia , Fraturas do Quadril/prevenção & controle , Humanos , Medicare , Osteoporose Pós-Menopausa/complicações , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/prevenção & controle , Proteína Relacionada ao Hormônio Paratireóideo/efeitos adversos , Pós-Menopausa , Teriparatida/efeitos adversos , Estados Unidos/epidemiologia
2.
Hum Reprod ; 36(7): 1871-1890, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-33956944

RESUMO

STUDY QUESTION: Can ovarian tissue morphology be better preserved whilst enabling histological molecular analyses following fixation with a novel fixative, neutral buffered formalin (NBF) with 5% acetic acid (referred to hereafter as Form-Acetic)? SUMMARY ANSWER: Fixation with Form-Acetic improved ovarian tissue histology compared to NBF in multiple species while still enabling histological molecular analyses. WHAT IS KNOWN ALREADY: NBF fixation results in tissue shrinkage in various tissue types including the ovary. Components of ovarian tissue, notably follicles, are particularly susceptible to NBF-induced morphological alterations and can lead to data misrepresentation. Bouin's solution (which contains 5% acetic acid) better preserves tissue architecture compared to NBF but is limited for immunohistochemical analyses. STUDY DESIGN, SIZE, DURATION: A comparison of routinely used fixatives, NBF and Bouin's, and a new fixative, Form-Acetic was carried out. Ovarian tissue was used from three different species: human (n = 5 patients), sheep (n = 3; 6 ovaries; 3 animals per condition) and mouse (n = 14 mice; 3 ovaries from 3 different animals per condition). PARTICIPANTS/MATERIALS, SETTING, METHODS: Ovarian tissue from humans (aged 13 weeks to 32 years), sheep (reproductively young i.e. 3-6 months) and mice (10 weeks old) were obtained and fixed in 2 ml NBF, Bouin's or Form-Acetic for 4, 8, and 24 h at room temperature. Tissues were embedded and sectioned. Five-micron sections were stained with haemotoxylin and eosin (H&E) and the percentage of artefact (clear space as a result of shrinkage) between ovarian structures was calculated. Additional histological staining using Periodic acid-Schiff and Masson's trichrome were performed on 8 and 24 h NBF, Bouin's and Form-Acetic fixed samples to assess the compatibility of the new fixative with stains. On ovarian tissue fixed for both 8 and 24 h in NBF and Form-Acetic, immunohistochemistry (IHC) studies to detect FOXO3a, FoxL2, collagen IV, laminin and anti-Müllerian hormone (AMH) proteins were performed in addition to the terminal deoxynucleotidyl transferase nick end labelling (TUNEL) assay to determine the compatibility of Form-Acetic fixation with types of histological molecular analyses. MAIN RESULTS AND THE ROLE OF CHANCE: Fixation in Form-Acetic improved ovarian tissue morphology compared to NBF from all three species and either slightly improved or was comparable to Bouin's for human, mouse and sheep tissues. Form-Acetic was compatible with H&E, Periodic acid-Schiff and Masson's trichrome staining and all proteins (FOXO3a, FoxL2, collagen IV and laminin and AMH) could be detected via IHC. Furthermore, Form-Acetic, unlike NBF, enabled antigen recognition for most of the proteins tested without the need for antigen retrieval. Form-Acetic also enabled the detection of damaged DNA via the TUNEL assay using fluorescence. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: In this study, IHC analysis was performed on a select number of protein types in ovarian tissue thus encouraging further studies to confirm the use of Form-Acetic in enabling the detection of a wider range of protein forms in addition to other tissue types. WIDER IMPLICATIONS OF THE FINDINGS: The simplicity in preparation of Form-Acetic and its superior preservative properties whilst enabling forms of histological molecular analyses make it a highly valuable tool for studying ovarian tissue. We, therefore, recommend that Form-Acetic replaces currently used fixatives and encourage others to introduce it into their research workflow. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Oxford Medical Research Council Doctoral Training Programme (Oxford MRC-DTP) grant awarded to B.D.B. (Grant no. MR/N013468/1), the Fondation Hoffmann supporting R.A. and the Petroleum Technology Development Fund (PTDF) awarded to B.V.A.


Assuntos
Formaldeído , Ovário , Preservação de Tecido/métodos , Ácido Acético , Animais , Hormônio Antimülleriano , Feminino , Fixadores , Humanos , Imuno-Histoquímica , Camundongos , Ovinos
3.
Osteoporos Int ; 31(12): 2413-2424, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32696118

RESUMO

We characterized patients initiating abaloparatide (ABL), teriparatide (TPTD), or denosumab (DMAB) in a real-world clinical setting from a large medical and pharmacy claims database. Differences were noted in sex, age, pathologic fractures, comorbidity index, and prior bisphosphonate use for patients initiating ABL and TPTD compared with those receiving DMAB. INTRODUCTION: To characterize patients initiating abaloparatide (ABL), teriparatide (TPTD), or denosumab (DMAB) treatment in a real-world clinical setting. METHODS: Patients aged ≥ 18 years initiating ABL, TPTD, or DMAB between May 1, 2017, and September 24, 2018 (without receiving the same drug in the previous 12 months), were identified using the OM1 Data Cloud, which contains medical and pharmacy claims from approximately 200 million US patients. The index date was the date of initial prescription or dispensing for ABL, TPTD, or DMAB during the study period. RESULTS: During the study period, 2666 patients initiated ABL, 9210 TPTD, and 116,718 DMAB. Mean age (standard deviation) was 69.2 (10.6) years for the ABL cohort, 68.6 (11.3) for TPTD, and 72.1 (10.2) for DMAB (P < 0.001; ABL vs DMAB). Proportionally more patients initiating ABL were female (95.2% ABL, 86.9% TPTD, and 91.3% DMAB, P < 0.001 ABL vs TPTD or DMAB). Nearly twice as many patients initiating ABL (19.1%) and TPTD (18.8%) had a previous pathologic/fragility fracture vs DMAB (9.6%; P < 0.001 ABL vs DMAB). Fewer patients initiating ABL (36.3%) or TPTD (39.7%) had Charlson comorbidity index of ≥ 2 vs DMAB (48.4%; P < 0.001 ABL vs DMAB). Before initiating ABL, TPTD, or DMAB, 44.3%, 33.8%, and 33.9% of patients had prior osteoporosis treatment, respectively. Bisphosphonate use was more common before initiating ABL (19.2%) or TPTD (19.6%), than before initiating DMAB (16.6%; P < 0.001 ABL vs DMAB). CONCLUSIONS: Patients initiating ABL and TPTD differed in sex, age, pathologic fractures, comorbidity index, and prior bisphosphonate use compared with those initiating DMAB.


Assuntos
Conservadores da Densidade Óssea , Osteoporose Pós-Menopausa , Idoso , Densidade Óssea , Conservadores da Densidade Óssea/uso terapêutico , Denosumab/uso terapêutico , Feminino , Humanos , Lactente , Masculino , Medicare , Proteína Relacionada ao Hormônio Paratireóideo , Teriparatida/uso terapêutico , Estados Unidos/epidemiologia
4.
Osteoporos Int ; 31(7): 1299-1304, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32062687

RESUMO

This study expands on previous findings that hip fracture rates may no longer be declining. We found that age- and sex-adjusted fracture rates in the US plateaued or increased through mid-2017 in a population of commercially insured and Medicare Advantage health plan enrollees, in contrast to a decline from 2007 to 2013. INTRODUCTION: The purpose of this study was to evaluate fracture trends in US commercial and Medicare Advantage health plan members aged ≥ 50 years between 2007 and 2017. METHODS: Retrospective analysis of the Optum Research Database from January 1, 2007, to May 31, 2017. RESULTS: Of 1,841,263 patients identified with an index fracture, 930,690 were case-qualifying and included in this analysis. The overall age- and sex-adjusted fracture rate decreased from 14.67/1000 person-years (py) in 2007 to 11.79/1000 py in 2013, followed by a plateau for the next 3 years and then an increase to 12.50/1000 py in mid-2017. In females aged ≥ 65 years, fracture rates declined from 27.49/1000 py in 2007 to 22.08/1000 py in 2013, then increased to 24.92/1000 py in mid-2017. Likewise, fracture rates in males aged ≥ 65 years declined from 2007 (12.00/1000 py) to 2013 (10.72/1000 py), then increased to 12.04/1000 py in mid-2017. The age- and sex-adjusted fracture rates for most fracture sites declined from 2007 to 2013 by 3.7% per year (P = 0.310). CONCLUSIONS: Following a consistent decline in fracture rate from 2007 to 2013, trends from 2014 to 2017 indicate fracture rates are no longer declining and, for some fracture types, rates are rising.


Assuntos
Fraturas do Quadril , Fraturas por Osteoporose , Adolescente , Idoso , Feminino , Fraturas do Quadril/epidemiologia , Humanos , Incidência , Masculino , Programas de Assistência Gerenciada , Medicare , Fraturas por Osteoporose/epidemiologia , Estudos Retrospectivos , Estados Unidos/epidemiologia
5.
Osteoporos Int ; 30(7): 1465-1473, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30953114

RESUMO

This network meta-analysis assessed the efficacy of abaloparatide versus other treatment options to reduce the risk of fractures in women with postmenopausal osteoporosis. The analysis indicates that abaloparatide reduces the risk of fractures in women with postmenopausal osteoporosis versus placebo and compared with other treatment options. INTRODUCTION: This network meta-analysis (NMA) assessed the relative efficacy of abaloparatide versus other treatments to reduce the risk of fractures in women with postmenopausal osteoporosis (PMO). METHODS: PubMed®, Embase®, and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials published before December 20, 2017, that included women with PMO who were eligible to receive interventions for primary or secondary fracture prevention. The NMA was conducted by fracture site (vertebral [VF], nonvertebral [NVF], and wrist), with the relative risk (RR) of fracture versus placebo the main clinical endpoint. The NMA used fixed-effects and random-effects approaches. RESULTS: A total of 4978 articles were screened, of which 22 were included in the analysis. Compared with other treatments, abaloparatide demonstrated the greatest treatment effect relative to placebo in the VF network (RR = 0.13; 95% credible interval [CrI] 0.04-0.34), the NVF network (RR = 0.50; 95% CrI 0.28-0.85), and the wrist fracture network (RR = 0.39; CrI 0.15-0.90). Treatment ranking showed that abaloparatide had the highest estimated probability of preventing fractures in each of the networks (79% for VF, 70% for NVF, and 53% for wrist fracture) compared with other treatments. Individual networks demonstrated a good level of agreement with direct trial evidence and direct pair-wise comparisons. CONCLUSIONS: This NMA indicates that abaloparatide reduces the RR of VF, NVF, and wrist fracture in women with PMO with or without prior fracture versus placebo, compared with other treatment options. Limitations include that adverse events and drug costs were not considered, and that generalizability is limited to the trial populations and endpoints included in the NMA.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Osteoporose Pós-Menopausa/tratamento farmacológico , Fraturas por Osteoporose/prevenção & controle , Proteína Relacionada ao Hormônio Paratireóideo/uso terapêutico , Fraturas da Coluna Vertebral/prevenção & controle , Feminino , Fraturas do Quadril/prevenção & controle , Humanos , Metanálise em Rede , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Comportamento de Redução do Risco , Traumatismos do Punho/prevenção & controle
6.
Reproduction ; 152(5): 591-601, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27581083

RESUMO

Premature ovarian insufficiency (POI) occurs in 1% of reproductive-age women. The ovarian manifestation ranges from the presence of a variable population of follicles (follicular) to the absence of follicles (afollicular), and in the majority of cases the cause is unknown. A transgenic mouse model of follicular POI, the Double Mutant (DM), arises from oocyte-specific deletion of Mgat1 and C1galt1 required for the generation of O- and N-glycans. DM females are subfertile at 6 weeks, infertile by 9 weeks and exhibit POI by 12 weeks of age. In this study we investigate the cause of the reduced fertility at 6 weeks and infertility at 9 weeks of DM females. Ovary sections were used to analyse follicle and corpora lutea (CL) numbers, apoptosis, and levels of laminin and 3ß-hydroxysteroid dehydrogenase using immunohistochemistry. After POI, DM females unexpectedly remained sexually receptive. At both 6 and 9 weeks, DM ovaries contained more primary follicles, however, at 9 weeks DM follicles were proportionally healthier, revealed by TUNEL analysis compared with Controls. In 9 week DM ovaries (collected post-mating), secondary follicles had theca and basal lamina structure abnormalities, whilst preovulatory follicles failed to ovulate resulting in the presence of numerous luteinised unruptured follicles, indicative of ovulation failure. Finally, DM ovaries contained more regressing CL with decreased luteal cell apoptosis indicative of a defect in CL regression. Identifying these follicular modifications have provided insight into the aetiology of a model of POI and highlight targets to investigate with the hope of developing new fertility treatments.


Assuntos
Aciltransferases/fisiologia , Fertilidade , Galactosiltransferases/fisiologia , Oócitos/patologia , Folículo Ovariano/patologia , Insuficiência Ovariana Primária/patologia , Animais , Feminino , Integrases/metabolismo , Camundongos , Camundongos Transgênicos , Mutação , N-Acetilglucosaminiltransferases , Oócitos/metabolismo , Folículo Ovariano/metabolismo , Ovulação/genética , Insuficiência Ovariana Primária/etiologia
7.
Reprod Fertil ; 2(4): L10-L12, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-35118414

RESUMO

To visualise tissues to determine the presence of disease or simply to understand anatomy, it is important to preserve fresh tissue. Fixatives are chemical solutions that preserve tissues to enable microscopic evaluation. However, some fixatives introduce artefact such as shrinkage of cells. Recently, a new fixative, Form-Acetic, was developed that is superior for preserving the structure of ovary tissue and allows investigation of ovary composition. One component of the ovary is hyaluronic acid (HA), which plays a crucial role in normal ovary function and fertility. Importantly, HA is sensitive to different fixative solutions. Therefore, it is meaningful to verify whether Form-Acetic is suitable for detecting HA. In this study, adult mouse ovaries were fixed in Form-Acetic and HA was detected. All HA-containing structures in the ovary were clearly distinguished which proves that the novel fixative allows the detection of HA.


Assuntos
Ácido Hialurônico , Ovário , Animais , Artefatos , Feminino , Fixadores , Camundongos , Fixação de Tecidos
8.
Science ; 261(5123): 879-85, 1993 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-8346440

RESUMO

The peptide alpha 4 is a designed four-helix bundle that contains a highly simplified hydrophobic core composed exclusively of leucine residues; its tertiary structure is therefore largely dictated by hydrophobic forces. This small protein adopts a structure with properties intermediate between those of the native and molten globule states of proteins: it is compact, globular, and has very stable helices, but its apolar side chains are mobile and not as well packed as in many natural proteins. To induce a more native-like state, two Zn(2+)-binding sites were introduced into the protein, thereby replacing some of the non-specific hydrophobic interactions with more geometrically restrictive metal-ligand interactions. In the metal-bound state, this protein has properties that approach those of native proteins. Thus, hydrophobic interactions alone are sufficient to drive polypeptide chain folding nearly to completion, but specific interactions are required for a unique structure.


Assuntos
Conformação Proteica , Proteínas/química , Zinco/química , Sequência de Aminoácidos , Naftalenossulfonato de Anilina/metabolismo , Sítios de Ligação , Histidina/química , Histidina/metabolismo , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Dobramento de Proteína , Estrutura Secundária de Proteína , Proteínas/síntese química , Proteínas/metabolismo , Termodinâmica
9.
Science ; 269(5229): 1409-13, 1995 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-7660123

RESUMO

Three supramolecular bischromophoric systems featuring zinc(II) and iron(III) porphyrins have been synthesized to evaluate the relative magnitudes of electronic coupling provided by hydrogen, sigma, and pi bonds. Laser flash excitation generates the highly reducing singlet excited state of the (porphinato)zinc chromophore that can subsequently be electron transfer quenched by the (porphinato)iron(III) chloride moiety. Measurement of the photoinduced electron transfer rate constants enables a direct comparison of how well these three types of chemical interactions facilitate electron tunneling. In contrast to generally accepted theory, electronic coupling modulated by a hydrogen-bond interface is greater than that provided by an analogous interface composed entirely of carbon-carbon sigma bonds. These results bear considerably on the analysis of through-protein electron transfer rate data as well as on the power of theory to predict the path traversed by the tunneling electron in a biological matrix; moreover, they underscore the cardinal role played by hydrogen bonds in biological electron transfer processes.


Assuntos
Transporte de Elétrons , Compostos Férricos/metabolismo , Ligação de Hidrogênio , Metaloporfirinas/metabolismo , Zinco/metabolismo , Compostos Férricos/química , Cinética , Metaloporfirinas/química , Oxirredução , Porfirinas/metabolismo , Termodinâmica , Zinco/química
10.
J Dev Orig Health Dis ; 9(6): 642-652, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30111388

RESUMO

Non-communicable diseases (NCDs) are a major problem as they are the leading cause of death and represent a substantial economic cost. The 'Developmental Origins of Health and Disease Hypothesis' proposes that adverse stimuli at different life stages can increase the predisposition to these diseases. In fact, adverse in utero programming is a major origin of these diseases due to the high malleability of embryonic development. This review provides a comprehensive analysis of the scientific literature on in utero programming and NCDs highlighting potential medical strategies to prevent these diseases based upon this programming. We fully address the concept and mechanisms involved in this programming (anatomical disruptions, epigenetic modifications and microbiota alterations). We also examine the negative role of in utero programming on the increased predisposition of NCDs in the offspring, which introduces the passive medical approach that consists of avoiding adverse stimuli including an unhealthy diet and environmental chemicals. Finally, we extensively discuss active medical approaches that target the causes of NCDs and have the potential to significantly and rapidly reduce the incidence of NCDs. These approaches can be classified as direct in utero programming modifications and personalized lifestyle pregnancy programs; they could potentially provide transgenerational NCDs protection. Active strategies against NCDs constitute a promising tool for the reduction in NCDs.


Assuntos
Suscetibilidade a Doenças/fisiopatologia , Desenvolvimento Embrionário/fisiologia , Estilo de Vida Saudável/fisiologia , Doenças não Transmissíveis/prevenção & controle , Efeitos Tardios da Exposição Pré-Natal/prevenção & controle , Dieta/efeitos adversos , Exposição Ambiental/efeitos adversos , Epigênese Genética/fisiologia , Feminino , Microbioma Gastrointestinal/fisiologia , Humanos , Exposição Materna/efeitos adversos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/etiologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia
11.
Clin Pharmacol Ther ; 81(1): 104-7, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17186007

RESUMO

A consistent framework for the acceptance and qualification of biomarkers for regulatory use is needed to facilitate innovative and efficient research and subsequent application of biomarkers in drug development. One key activity is biomarker qualification, a graded, "fit-for-purpose" evidentiary process linking a biomarker with biology and clinical end points. A biomarker consortium model will distribute cost and risk, and drive efficient execution of research and ultimately regulatory acceptance of biomarkers for specific indications.


Assuntos
Biomarcadores , Avaliação de Medicamentos/métodos , Determinação de Ponto Final , Projetos de Pesquisa , Tomada de Decisões , Humanos , Reprodutibilidade dos Testes , Resultado do Tratamento
12.
Acta Trop ; 101(2): 153-8, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17303060

RESUMO

A cross-sectional sero-epidemiological study was conducted to determine the prevalence of dengue in Trinidad. Two commercial rapid test kits, PanBio Dengue Duo IgM and IgG Rapid Strip Test and the Bio-Check Plus Dengue G/M Cassette Test (Brittney) were used. The immunosorbent assay (ELISA) (FOCUS Technologies, California) was used as the control. One hundred and twenty five cord blood samples were collected (46 from Mt. Hope Women's Hospital (MH) and 79 from the San Fernando General Hospital (SF)). All blood samples were tested in accordance with the two rapid kits and ELISA assay manufacturer's instructions. From 125 cord blood samples, the IgG FOCUS ELISA results showed 93.5 and 95% infections at MH and SF, respectively. Whereas the Brittney and PanBio kits showed 10.9 and 5.1%, and 26.1 and 50.6% for MH and SF, respectively. Based on the FOCUS ELISA (control) assays, the combined seroprevalence rate from north and south Trinidad was 94.4%. IgG and IgM sensitivity and specificity levels were higher in the PanBio than Brittney test kits. The high seroprevalence rates observed in Trinidad are discussed to stimulate more research to explain this phenomenon and to prevent the Southeast Asian scenario from developing in the Americas.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Dengue/imunologia , Dengue/epidemiologia , Sangue Fetal/imunologia , Kit de Reagentes para Diagnóstico , Adulto , Dengue/imunologia , Dengue/virologia , Ensaio de Imunoadsorção Enzimática , Feminino , Sangue Fetal/virologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Recém-Nascido , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Fatores de Tempo , Trinidad e Tobago/epidemiologia
13.
Nucleic Acids Res ; 29(7): 1476-83, 2001 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-11266549

RESUMO

The SfiI endonuclease cleaves DNA at the sequence GGCCNNNN NGGCC, where N is any base and downward arrow is the point of cleavage. Proteins that recognise discontinuous sequences in DNA can be affected by the unspecified sequence between the specified base pairs of the target site. To examine whether this applies to SFII, a series of DNA duplexes were made with identical sequences apart from discrete variations in the 5 bp spacer. The rates at which SFII cleaved each duplex were measured under steady-state conditions: the steady-state rates were determined by the DNA cleavage step in the reaction pathway. SFII cleaved some of these substrates at faster rates than other substrates. For example, the change in spacer sequence from AACAA to AAACA caused a 70-fold increase in reaction rate. In general, the extrapolated values for k(cat) and K(m) were both higher on substrates with inflexible spacers than those with flexible structures. The dinucleotide at the site of cleavage was largely immaterial. SFII activity is thus highly dependent on conformational variations in the spacer DNA.


Assuntos
Sítios de Ligação/genética , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Sequência de Bases , Ligação Competitiva , DNA/genética , DNA/metabolismo , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , Ligação Proteica , Especificidade por Substrato
14.
Arch Dis Child ; 101(12): 1119-1124, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27609019

RESUMO

INTRODUCTION: Multiple nutritional risk assessment tools are available, but there are limited data on their application in the acute setting. We explored the validity of two tools in a tertiary Children's Hospital's acute unit and the cohort's nutritional status using WHO definitions. METHODS: Prospective study n=300 (median 38 months; 44.6% female; 25.7% ≤12 months). Participants had standard anthropometry measured, all were screened using the Screening Tool for the Assessment of Malnutrition in Paediatrics (STAMP), the Paediatric Malnutrition Screening Tool (PMST) (modified STAMP) and 125 were additionally screened using the Paediatric Yorkhill Malnutrition Screening (PYMS) tool. RESULTS: The percentages with medium/high nutritional risk were as follows: STAMP 73.1%, PMST 79.3% and PYMS 30%. Height/weight were normally distributed with: 3.4% stunted (height-for-age z-score <-2); aged ≤ 5 years, 6.8% wasted (weight-for-height z-score (WHZ) <-2), 17.9% overweight (WHZ 1-2) and 6.2% obese (WHZ >2); aged >5 years, 5.8% thin (body mass index (BMI)-z-score (BAZ) <-2), 17.3% overweight (BAZ 1-2) and 5.8% obese (BAZ >2). The tools showed poor specificity and variable sensitivities when compared with WHO malnutrition criteria, with positive predictive values of <50%. κ-Analysis also showed poor agreement between the tools and the WHO cut-offs. CONCLUSION: These results suggest that nutritional screening tools have poor sensitivity and are difficult to interpret in the acute setting. It may be more effective to include the assessment of weight and height and nutritional intake in the context of the acute presentation as part of routine clinical assessment rather than relying on screening tools to identify those at risk.


Assuntos
Transtornos da Nutrição Infantil/diagnóstico , Avaliação Nutricional , Doença Aguda , Antropometria/métodos , Pré-Escolar , Inglaterra , Feminino , Humanos , Masculino , Estado Nutricional/fisiologia , Prognóstico , Estudos Prospectivos , Medição de Risco/métodos
15.
Biochim Biophys Acta ; 1159(2): 155-61, 1992 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-1390921

RESUMO

A complete understanding of the accelerating mechanisms of plasminogen activation and fibrinolysis necessarily requires structural information on the conformational forms of plasminogen. Given the absence of high-resolution structural data on plasminogen the use of lower resolution approaches has been adopted. Two such approaches have previously indicated a compact conformation of Glu-plasminogen (Tranqui, L., Prandini, M., and Chapel, A. (1979) Biol. Cellulaire, 34, 39-42; Bányai, L. and Patthy, L. (1985) Biochim. Biophys. Acta, 832, 224-227) whereas a third has suggested a fairly extended conformation (Mangel, W., Lin, B. and Ramakrishnan, V. (1990) Science, 248, 69-73). Native Glu-plasminogen has been investigated using small-angle X-ray scattering (SAXS) experiments. It is concluded that this molecule in solution is compact (radius of gyration, RG 3.05 +/- 0.02 nm and maximum intramolecular distance, Im 9.1 +/- 0.3 nm) and that the data are consistent with the right-handed spiral structure observed using electron microscopy by Tranqui et al. (1979). A spiral structure of native plasminogen would have important implications for the conformational response of plasminogen to fibrin and concomitant stimulation of plasminogen activation.


Assuntos
Plasminogênio/química , Simulação por Computador , Humanos , Modelos Moleculares , Conformação Proteica , Espalhamento de Radiação , Soluções
16.
J Mol Biol ; 289(4): 785-97, 1999 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-10369761

RESUMO

The synapsis of DNA sites is a prerequisite for the reactions of many proteins that act at specific DNA sequences. The requirement for synapsis was investigated by analysing the reactions of Sfi I, a tetrameric restriction enzyme that cleaves DNA only after interacting with two recognition sites. In the presence of Mg2+, oligonucleotide duplexes with the cognate recognition sequence were cleaved rapidly, with cooperative kinetics, while non-cognate duplexes were not cleaved. In the absence of Mg2+, the primary complex formed by Sfi I with cognate DNA contained two duplexes synapsed by the tetramer: a secondary complex containing one duplex was seen only at elevated Sfi I concentrations. In contrast, the principal complex with non-cognate DNA contained one duplex bound to Sfi I. Pairs of non-cognate duplexes, or one cognate and one non-cognate duplex, generally failed to form synaptic complexes. On adding Mg2+to complexes with cognate DNA, cleavage occurred much more rapidly in the synaptic complex than in the secondary complex. DNA synapsis thus acts to enhance the specificity of Sfi I for its recognition sequence, by demanding two cognate sites for a catalytically active complex and by excluding non-cognate sites from the synaptic complex.


Assuntos
DNA/metabolismo , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Catálise , Oligodesoxirribonucleotídeos/metabolismo , Ligação Proteica , Especificidade por Substrato
17.
Curr Opin Biotechnol ; 5(1): 34-9, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7512847

RESUMO

The use of cDNA libraries has become increasingly widespread as new techniques for library construction and analysis have become available. In recent years, interest in cell-type or stage-specific gene expression has necessitated the construction of cDNA libraries from very small numbers of cells. Recent advances in techniques of RNA isolation, cDNA synthesis, library construction, and the use of the polymerase chain reaction have made this a realistic goal.


Assuntos
DNA Complementar/síntese química , DNA Complementar/genética , Biblioteca Gênica , Animais , Biotecnologia , Clonagem Molecular , DNA Complementar/química , Vetores Genéticos , Humanos , Metilação , Reação em Cadeia da Polimerase , RNA/genética , RNA/isolamento & purificação
18.
Leukemia ; 10(12): 1980-9, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8946941

RESUMO

Burkitt's lymphoma is characterized by a translocation of the c-myc gene with one of the immunoglobulin loci which activates overexpression of the c-myc oncogene. Antisense-oligodeoxynucleotides (AS-ODNs) offer the potential to block specific c-myc gene expression within lymphoma cells, but often exhibit a low efficiency of AS-ODN uptake. In this study, a polycationic lipid reagent, Lipofectamine (LFM), was utilized as a vehicle to increase efficiency of delivery, decrease the time needed to observe an inhibitory effect, and decrease the AS-ODN dose. The objective was to develop a more efficient and rapid in vitro AS-ODN strategy to inhibit proliferation of c-myc-dependent lymphoma cells and to test the specificity of Burkitt's lymphoma cell line-directed AS-ODNs for potential use as molecular purging agents in bone marrow transplantation. Proliferation assays were performed to determine the inhibitory effect of the AS-ODNs on two Burkitt's lymphoma cell lines with different chromosomal translocations, Daudi and ST486, in medium containing 8.5 microM LFM. AS-ODNs at a concentration of 0.36 microM induced a significant decrease in proliferation for both cell lines using the specific AS-ODN for each respective translocation. Within 5 h, Daudi responded to its specific AS-ODN/lipid complexes with a 35% decrease in proliferation, compared to cells which received no treatment or Daudi-specific AS-ODN without LFM (P = 0.0001). Daudi showed an insignificant decrease in proliferation when treated with an AS-ODN specific for the ST486 translocation (4%, P = 0.26). ST486 proliferation was decreased by 52% when treated with the specific antisense for ST486 compared to no treatment or ST486-specific AS-ODN without LFM (P < 0.003). Treatment with the AS-ODN specific for Daudi showed an insignificant 4% decrease (P = 0.42). Controls, including sense ODN for structure, reverse AS-ODN for structure and base composition, and AS-ODN without LFM, did not produce a significant change in cells treated with LFM alone or cells receiving no treatment. Clonogenic assays of both Daudi and ST486 treated with their specific AS-ODNs revealed a 50% inhibition of colony formation after the 5 h incubation as compared to no treatment. Confocal laser scanning microscopy verified that cellular uptake of AS-ODN was enhanced by cationic lipids. Immunoblot analysis showed a 63 +/- 5% and a 50 +/- 3% reduction in intracellular c-myc levels for Daudi and ST486, respectively, when their respective AS-ODNs were administered. Normal bone marrow progenitors were unaffected by the ODN/LFM complexes. These results suggest that the specific c-myc AS-ODN/LFM complexes inhibit c-myc-dependent tumor proliferation at an earlier time and at a lower dose compared to no lipid facilitation. This approach may form the basis for utilizing specific AS-ODN/LFM therapy either alone or in a cocktail of other agents as an ex vivo molecular purging approach to autologous stem cell transplantation in Burkitt's lymphoma.


Assuntos
Linfoma de Burkitt/tratamento farmacológico , Linfoma de Burkitt/genética , Resinas de Troca de Cátion/farmacologia , Genes myc , Lipídeos/farmacologia , Oligonucleotídeos Antissenso/farmacologia , Adulto , Animais , Linfoma de Burkitt/patologia , Resinas de Troca de Cátion/administração & dosagem , Cátions , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Esquema de Medicação , Sinergismo Farmacológico , Humanos , Cinética , Lipídeos/administração & dosagem , Oligonucleotídeos Antissenso/administração & dosagem , Oligonucleotídeos Antissenso/farmacocinética , Sensibilidade e Especificidade , Translocação Genética
19.
J Clin Endocrinol Metab ; 81(2): 745-51, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8636298

RESUMO

We recently suggested that placentally derived CRH might influence human parturition via specific receptor mechanisms. We identified a human myometrial CRH receptor that changes to a high affinity state in the later stages of pregnancy and becomes coupled to the adenylate cyclase system. The purpose of this study was to investigate the functional capacity of this receptor in myometrial tissue obtained from women being delivered electively by cesarian section at term (38-40 weeks gestation) and preterm (30-35 weeks gestation) before the onset of labor. Myometrial membrane suspensions were prepared by differential centrifugation, and the production of cAMP after stimulation with various test substances was measured by RIA. In preterm myometrium, both human CRH and cholera toxin stimulated cAMP production. This effect was significantly reduced in term myometrium. The adenylate cyclase was functionally active in term myometrium, as demonstrated by the use of forskolin. Furthermore, pertussis toxin pretreatment of term myometrial membranes did not increase the response to CRH. These results suggest that in human pregnant myometrium at term, there is a modification in the coupling mechanisms between CRH receptors and the catalytic component of adenylate cyclase, resulting in a reduction of CRH-stimulated cAMP production.


Assuntos
Adenilil Ciclases/metabolismo , Miométrio/metabolismo , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Toxina Adenilato Ciclase , Membrana Celular/metabolismo , Toxina da Cólera/farmacologia , Colforsina/farmacologia , Hormônio Liberador da Corticotropina/farmacologia , AMP Cíclico/biossíntese , Feminino , Humanos , Isoproterenol/farmacologia , Toxina Pertussis , Gravidez , Terceiro Trimestre da Gravidez , Fatores de Virulência de Bordetella/farmacologia
20.
Biol Psychiatry ; 46(3): 374-82, 1999 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-10435203

RESUMO

BACKGROUND: Although schizophrenic and control subjects differ on a variety of neuroanatomical measures, the specificity and sensitivity of any one measure for differentiating between groups are low. This study investigated the cumulative effect of deviant brain structure on diagnosis. METHODS: Hemisphere and third ventricle volume and the normalized (Talairach) location of three association cortex sulcal landmarks were measured on high-resolution MRI scans in 37 male patients with schizophrenia and 33 male control subjects matched on age, handedness, and parental socioeconomic status. RESULTS: While there were few group differences on individual anatomical measures, the 10 variables reliably discriminated between the two groups when used in concert in a discriminant function analysis (F[10.59] = 3.6, p < .0009) with 77% of the subjects correctly classified. Five of the measures (left posterior cingulate, left inferior frontal sulcus, right sylvian fissure, and left and right halves of the third ventricle) correlated significantly with the discriminant function (p < .005). CONCLUSIONS: This is the first study to demonstrate that schizophrenics can be distinguished from matched controls on the basis of brain anatomy alone. The risk of schizophrenia may depend on the total amount of neural deviance, rather than on anomalies in a single structure or circuit.


Assuntos
Encéfalo/anormalidades , Esquizofrenia/genética , Adolescente , Adulto , Ventrículos Cerebrais/anormalidades , Lateralidade Funcional/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Esquizofrenia/diagnóstico , Sensibilidade e Especificidade , Fatores Socioeconômicos
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