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1.
Bioresour Technol ; 396: 130412, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38310977

RESUMO

This study presents a fractional calculus model as a generalized kinetic model for estimating the maximum methane yield and degradation kinetics in biomethane potential (BMP) assays, a key analytical method in anaerobic digestion research and application. The fractional model outperformed common first-order kinetic models by yielding superior data fitting and properly managing substrate heterogeneity. The fractional model showed robust performance in mono-digestion, co-digestion and pre-treatment BMP assays with or without presence of large tailing or sigmoidal patterns in the BMP curve. The main advantage of the fractional model over other models is its ability to capture the complexities of the methane production process without losing model accuracy. Assessment of the mathematical model revealed that for fractional orders greater than 0.8 the Mittag-Leffler sequence could be transformed into a more computationally efficient exponential function.


Assuntos
Metano , Modelos Teóricos , Anaerobiose , Reatores Biológicos
2.
Nat Commun ; 14(1): 5274, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37726314

RESUMO

Argyle is the world's largest source of natural diamonds, yet one of only a few economic deposits hosted in a Paleoproterozoic orogen. The geodynamic triggers responsible for its alkaline ultramafic volcanic host are unknown. Here we show, using U-Pb and (U-Th)/He geochronology of detrital apatite and detrital zircon, and U-Pb dating of hydrothermal titanite, that emplacement of the Argyle lamproite is bracketed between 1311 ± 9 Ma and 1257 ± 15 Ma (2σ), older than previously known. To form the Argyle lamproite diatreme complex, emplacement was likely driven by lithospheric extension related to the breakup of the supercontinent Nuna. Extension facilitated production of low-degree partial melts and their migration through transcrustal corridors in the Paleoproterozoic Halls Creek Orogen, a rheologically-weak rift zone adjacent to the Kimberley Craton. Diamondiferous diatreme emplacement during (super)continental breakup may be prevalent but hitherto under-recognized in rift zones at the edges of ancient continental blocks.

3.
Food Res Int ; 137: 109475, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33233141

RESUMO

Salting is one of the oldest methods of preserving food. The main limitation of salting is its extended processing time due to slow salt diffusion. A moderate electric field (MEF) can improve the mass transfer rate through electroporation. Regularly, mass transfer processes are modeled with Fick's second law. However, due to the anisotropic nature of food microstructures, it might be more appropriate to use an anomalous model. The main objective of this study was to search for a phenomenological explanation for salt and water diffusion in the salmon brining process coupled with MEF. Salmon fillets were cut into finite cylinders (0.025 × 0.025 m) and brined in two salt concentrations (6 and 24% w/w NaCl) at 6 °C for 20 h. MEFs were applied in the range of 0 to 2 V/cm. The salt and water contents of the salmon were measured during the process. Fick's second law and anomalous model based on fractional calculus were used to describe the diffusion phenomena. The results showed that an MEF tended to reduce the brining processing time and increase the salt content of salmon. This effect is predominantly due to an increase in the equilibrium salt concentration in the salmon tissue. Mathematical analysis shows that the anomalous diffusion model is more suitable for representing the brining process, exhibiting superdiffusion behavior (α > 1). An MEF accelerates the salt mass transfer into salmon tissue even at lower temperatures, significantly reducing the processing time. In addition, the diffusion process can be characterized with an anomalous model.


Assuntos
Salmo salar , Cloreto de Sódio , Animais , Manipulação de Alimentos , Alimentos Marinhos , Cloreto de Sódio na Dieta
4.
Science ; 365(6454): 692-694, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31416962

RESUMO

Isotope compositions of basalts provide information about the chemical reservoirs in Earth's interior and play a critical role in defining models of Earth's structure. However, the helium isotope signature of the mantle below depths of a few hundred kilometers has been difficult to measure directly. This information is a vital baseline for understanding helium isotopes in erupted basalts. We measured He-Sr-Pb isotope ratios in superdeep diamond fluid inclusions from the transition zone (depth of 410 to 660 kilometers) unaffected by degassing and shallow crustal contamination. We found extreme He-C-Pb-Sr isotope variability, with high 3He/4He ratios related to higher helium concentrations. This indicates that a less degassed, high-3He/4He deep mantle source infiltrates the transition zone, where it interacts with recycled material, creating the diverse compositions recorded in ocean island basalts.

5.
Food Sci Technol Int ; 25(5): 414-428, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30714395

RESUMO

The design and development of gluten-free foods requires a comprehensive understanding of the behavior of the raw materials to attain the same cooking and nutritional quality as gluten-based food. The objective of this study was to determine the optimal hot-air drying conditions for elaboration of cassava flour to be used in a gluten-free pasta formulation. The results showed that the operational conditions to minimize the hot-air drying time (57 min) to produce cassava flour with higher water holding capacity was 57 ℃ at 3 m/s. Then, the optimal formulation for the pasta was found to be cassava (26 g/100 g), amaranth flour (12 g/100 g), and carboxymethyl cellulose (0.23 g/100 g), which maximized the Aw (0.160), moisture content (3.10 g/100 g), hardness (5.02 N), and protein content (9.30 g/100 g), and it is used for the sensorial analysis, which showed that an earthy taste was the main problem with consumer satisfaction.


Assuntos
Dessecação/métodos , Dieta Livre de Glúten , Manihot/química , Amaranthus/química , Doença Celíaca/dietoterapia , Fenômenos Químicos , Comportamento do Consumidor , Proteínas Alimentares/análise , Temperatura Alta , Tubérculos/química , Paladar , Água/análise
6.
Gait Posture ; 61: 197-203, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29353745

RESUMO

BACKGROUND: Rigid attachment systems are one of the methods used to compensate for soft tissue artifact (STA) inherent in joint motion analyses. RESEARCH QUESTION: The goal of this study was to quantify STA of an exoskeleton design to reduce STA at the knee, and to assess the accuracy of 3D knee kinematics recorded with the exoskeleton in non-obese and obese subjects during quasi-static weight-bearing squatting activity using biplane radiography. METHODS: Nine non-obese and eight obese subjects were recruited. The exoskeleton was calibrated on each subject before they performed a quasistatic squatting activity in the EOS® imaging system. 3D models of exoskeleton markers and knee bones were reconstructed from EOS® radiographs; they served to quantify STA and to evaluate differences between the markers and bones knee kinematics during the squatting activity. RESULTS: The results showed that STA observed at the femur was larger in non-obese subjects than in obese subjects in frontal rotation (p = 0.004), axial rotation (p = 0.000), medio-lateral displacement (p = 0.000) and antero-posterior displacement (p = 0.019), while STA observed at the tibia was lower in non-obese subjects than in obese subjects for the three rotations (p < 0.05) and medio-lateral displacement (p = 0.015). Differences between the markers and bones knee kinematics increased with knee flexion and were similar in both groups, except for abduction-adduction: 4.9° for non-obese subjects against 2.3° for obese subjects (p = 0.011). SIGNIFICANCE: This study demonstrated that STA at the femur and its impact on knee abduction-adduction using a specific exoskeleton were greater among non-obese subjects than obese subjects, which is encouraging for future biomechanical studies on pathologies such as osteoarthritis.


Assuntos
Artefatos , Articulação do Joelho/fisiologia , Obesidade/fisiopatologia , Adulto , Fenômenos Biomecânicos , Exercício Físico/fisiologia , Exoesqueleto Energizado , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular , Suporte de Carga/fisiologia , Adulto Jovem
7.
J Clin Endocrinol Metab ; 102(7): 2595-2603, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28368485

RESUMO

Context: Islet amyloid is a feature of ß-cell failure in type 2 diabetes (T2D) and type 1 diabetes (T1D) recipients of islet transplants. Islet amyloid contains islet amyloid polypeptide (IAPP; amylin), a circulating peptide that is produced in ß cells by processing of its precursor, proIAPP1-67, via an intermediate form, proIAPP1-48. Elevated proinsulin to C-peptide ratios in the plasma of persons with diabetes suggest defects in ß-cell prohormone processing. Objective: Determine whether plasma levels of precursor forms of IAPP are elevated in diabetes. Design, Setting, and Patients: We developed an immunoassay to detect proIAPP1-48 in human plasma, and we determined the ratio of proIAPP1-48 to mature IAPP in subjects with T1D, T2D, recipients of islet transplants, and healthy controls. Results: The proIAPP1-48 immunoassay had a limit of detection of 0.18 ± 0.06 pM and cross-reactivity with intact proIAPP1-67 <15%. Healthy individuals had plasma concentrations of proIAPP1-48 immunoreactivity of 1.5 ± 0.2 pM and a proIAPP1-48 to total IAPP ratio of 0.28 ± 0.03. Plasma concentrations of proIAPP1-48 immunoreactivity were not significantly different in subjects with T2D but were markedly increased in T1D recipients of islet transplants. Children and adults with T1D had reduced mature IAPP levels relative to age-matched controls but an elevated ratio of proIAPP1-48 to total IAPP. Conclusion: The ß cells in T1D and islet transplants have impaired processing of the proIAPP1-48 intermediate. The ratio of proIAPP1-48-to-IAPP immunoreactivity may have value as a biomarker of ß-cell stress and dysfunction.


Assuntos
Amiloide/metabolismo , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 2/sangue , Polipeptídeo Amiloide das Ilhotas Pancreáticas/sangue , Transplante das Ilhotas Pancreáticas , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 1/cirurgia , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/cirurgia , Ensaio de Imunoadsorção Enzimática , Feminino , Seguimentos , Humanos , Imunoensaio , Masculino , Pessoa de Meia-Idade , Proinsulina/metabolismo , Valores de Referência , Medição de Risco
8.
Interação psicol ; 21(1): 19-27, jan.-abr. 2017.
Artigo em Português | Index Psicologia - Periódicos | ID: psi-70832

RESUMO

O setor bancário sofre mudanças importantes desde a reestruturação produtiva na década de90, implicando redução significativa no contingente de trabalhadores e transformações na or-ganização do trabalho. Estas contingências impactam na saúde mental do bancário, sendo re-levante investigar os mecanismos de mediação e defesa do sofrimento utilizados pelostrabalhadores diante deste contexto. Esta pesquisa descritiva, de abordagem qualitativa, foirealizada por meio de entrevistas com bancários de instituição privada de atuação nacional,submetidas à análise de conteúdo. A investigação identificou os efeitos da organização dotrabalho, onde as premissas da gestão geram importante individualização do trabalho, pois obancário é tensionado pela pressão da meta e pela necessidade de reconhecimento. Há mobi-lização subjetiva no sentido de tentar mediar o sofrimento decorrente da dinâmica do traba-lho, como evidenciado na superficialidade afetiva e no isolamento que busca dar conta dademanda de atribuições imposta, o que se reflete na condição de atendimento aos clientes.Dentre as estratégias de mediação presentes nas experiências dos participantes estão a coo-peração, a inteligência prática e a transgressão; como mecanismos de defesa, foram identifi-cados o cinismo viril, a insensibilidade afetiva, o isolamento e o adoecimento psíquico(AU)


Assuntos
Humanos , Masculino , Feminino , Adulto , Categorias de Trabalhadores/psicologia , Esgotamento Profissional/psicologia
9.
Comput Methods Biomech Biomed Engin ; 20(1): 94-103, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27347737

RESUMO

Knee joint kinematics derived from multi-body optimisation (MBO) still requires evaluation. The objective of this study was to corroborate model-derived kinematics of osteoarthritic knees obtained using four generic knee joint models used in musculoskeletal modelling - spherical, hinge, degree-of-freedom coupling curves and parallel mechanism - against reference knee kinematics measured by stereo-radiography. Root mean square errors ranged from 0.7° to 23.4° for knee rotations and from 0.6 to 9.0 mm for knee displacements. Model-derived knee kinematics computed from generic knee joint models was inaccurate. Future developments and experiments should improve the reliability of osteoarthritic knee models in MBO and musculoskeletal modelling.


Assuntos
Articulação do Joelho/anatomia & histologia , Modelos Biológicos , Osteoartrite/diagnóstico , Postura/fisiologia , Idoso , Fenômenos Biomecânicos , Índice de Massa Corporal , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular , Reprodutibilidade dos Testes
10.
Diabetologia ; 60(3): 453-463, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27999871

RESUMO

AIMS/HYPOTHESIS: A contributor to beta cell failure in type 2 diabetes and islet transplants is amyloid formation by aggregation of the beta cell peptide, islet amyloid polypeptide (IAPP). Similar to the proinsulin processing pathway that generates insulin, IAPP is derived from a prohormone precursor, proIAPP, which requires cleavage by prohormone convertase (PC) 1/3 and PC2 in rodent pancreatic beta cells. We hypothesised that loss of PC2 would promote beta cell death and dysfunction in a rodent model of human beta cell proIAPP overexpression. METHODS: We generated an islet transplant model wherein immune-deficient mouse models of diabetes received islets expressing amyloidogenic human proIAPP and lacking PC2, leading to restoration of normoglycaemia accompanied by increased secretion of human proIAPP. Blood glucose levels were analysed for up to 16 weeks in transplant recipients and grafts were assessed for islet amyloid and beta cell number and death. RESULTS: Hyperglycaemia (blood glucose >16.9 mmol/l) returned in 94% of recipients of islets expressing human proIAPP and lacking PC2, whereas recipients of islets that express human proIAPP and normal PC2 levels remained normoglycaemic for at least 16 weeks. Islet graft failure was accompanied by a ∼20% reduction in insulin-positive cells, yet the degree of amyloid deposition and beta cell apoptosis was similar to those of controls expressing human proIAPP with functional PC2 levels. CONCLUSIONS/INTERPRETATION: PC2 deficiency in transplanted mouse islets expressing human proIAPP promotes beta cell loss and graft failure. Our data suggest that impaired NH2-terminal processing and increased secretion of human proIAPP promote beta cell failure.


Assuntos
Amiloide/metabolismo , Células Secretoras de Insulina/metabolismo , Pró-Proteína Convertase 2/metabolismo , Amiloide/genética , Animais , Glicemia/metabolismo , Western Blotting , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Transplante das Ilhotas Pancreáticas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos SCID , Proinsulina/metabolismo , Pró-Proteína Convertase 1/genética , Pró-Proteína Convertase 1/metabolismo , Pró-Proteína Convertase 2/genética
11.
J Biomech ; 48(14): 3796-802, 2015 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-26472302

RESUMO

Soft tissue artifact (STA) distort marker-based knee kinematics measures and make them difficult to use in clinical practice. None of the current methods designed to compensate for STA is suitable, but multi-body optimization (MBO) has demonstrated encouraging results and can be improved. The goal of this study was to develop and validate the performance of knee joint models, with anatomical and subject-specific kinematic constraints, used in MBO to reduce STA errors. Twenty subjects were recruited: 10 healthy and 10 osteoarthritis (OA) subjects. Subject-specific knee joint models were evaluated by comparing dynamic knee kinematics recorded by a motion capture system (KneeKG™) and optimized with MBO to quasi-static knee kinematics measured by a low-dose, upright, biplanar radiographic imaging system (EOS(®)). Errors due to STA ranged from 1.6° to 22.4° for knee rotations and from 0.8 mm to 14.9 mm for knee displacements in healthy and OA subjects. Subject-specific knee joint models were most effective in compensating for STA in terms of abduction-adduction, inter-external rotation and antero-posterior displacement. Root mean square errors with subject-specific knee joint models ranged from 2.2±1.2° to 6.0±3.9° for knee rotations and from 2.4±1.1 mm to 4.3±2.4 mm for knee displacements in healthy and OA subjects, respectively. Our study shows that MBO can be improved with subject-specific knee joint models, and that the quality of the motion capture calibration is critical. Future investigations should focus on more refined knee joint models to reproduce specific OA knee geometry and physiology.


Assuntos
Articulação do Joelho/fisiopatologia , Modelagem Computacional Específica para o Paciente , Adulto , Idoso , Artefatos , Fenômenos Biomecânicos , Humanos , Pessoa de Meia-Idade , Osteoartrite do Joelho/patologia , Osteoartrite do Joelho/fisiopatologia , Amplitude de Movimento Articular/fisiologia , Rotação
12.
Diabetologia ; 58(3): 575-85, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25491100

RESUMO

AIMS/HYPOTHESIS: Aggregation of islet amyloid polypeptide (IAPP) to form amyloid contributes to beta cell dysfunction in type 2 diabetes. Human but not non-amyloidogenic rodent IAPP induces islet macrophage proIL-1ß synthesis. We evaluated the effect of IL-1 receptor antagonist (IL-1Ra) on islet inflammation and dysfunction in a mouse model of type 2 diabetes with amyloid formation. METHODS: Lean and obese male mice (A/a or A(vy)/A at the agouti locus, respectively) with or without beta cell human IAPP expression (hIAPP(Tg/0)) were treated with PBS or IL-1Ra (50 mg kg(-1) day(-1)) from 16 weeks of age. Intraperitoneal glucose and insulin tolerance tests were performed after 8 weeks. Pancreases were harvested for histology and gene expression analysis. RESULTS: Aggregation of human IAPP was associated with marked upregulation of proinflammatory gene expression in islets of obese hIAPP(Tg/0) mice, together with amyloid deposition and fasting hyperglycaemia. IL-1Ra improved glucose tolerance and reduced plasma proinsulin:insulin in both lean and obese hIAPP(Tg/0) mice with no effect on insulin sensitivity. The severity and prevalence of islet amyloid was reduced by IL-1Ra in lean hIAPP (Tg/0) mice, suggesting a feed-forward mechanism by which islet inflammation promotes islet amyloid at the early stages of disease. IL-1Ra limited Il1a, Il1b, Tnf and Ccl2 expression in islets from obese hIAPP(Tg/0) mice, suggesting an altered islet inflammatory milieu. CONCLUSIONS/INTERPRETATION: These data provide the first in vivo evidence­using a transgenic mouse model with amyloid deposits resembling those found in human islets­that IAPP-induced beta cell dysfunction in type 2 diabetes may be mediated by IL-1. Anti-IL-1 therapies may limit islet inflammation and dysfunction associated with amyloid formation.


Assuntos
Amiloide/metabolismo , Interleucina-1/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Animais , Humanos , Imuno-Histoquímica , Inflamação/metabolismo , Interleucina-1/genética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/genética , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Camundongos Transgênicos
14.
Appl Microbiol Biotechnol ; 93(1): 285-93, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21874276

RESUMO

AmyR is commonly considered a regulator of starch degradation whose activity is induced by the presence of maltose, the disaccharide building block of starch. In this study, we demonstrate that the role of AmyR extends beyond starch degradation. Enzyme activity assays, genes expression analysis and growth profiling on D-glucose- and D-galactose-containing oligo- and polysaccharides showed that AmyR regulates the expression of some of the Aspergillus niger genes encoding α- and ß-glucosidases, α- and ß- galactosidases, as well as genes encoding α-amlyases and glucoamylases. In addition, we provide evidence that D-glucose or a metabolic product thereof may be the inducer of the AmyR system in A. niger and not maltose, as is commonly assumed.


Assuntos
Aspergillus niger/metabolismo , Proteínas Fúngicas/metabolismo , Galactose/metabolismo , Regulação Bacteriana da Expressão Gênica , Glucose/metabolismo , Polissacarídeos/metabolismo , Transativadores/metabolismo , Aspergillus niger/genética , Proteínas Fúngicas/genética , Níger , Transativadores/genética
15.
Eur Respir J ; 38(5): 1071-80, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21478216

RESUMO

This international phase III study of inhaled dry powder mannitol was a randomised, double-blind, 26-week study, followed by a further 26-week, open-label (OL) extension. 324 cystic fibrosis (CF) patients were randomised, in a 3:2 ratio, to mannitol (400 mg b.i.d.) and control groups. The primary efficacy end-point was to determine the change in forced expiratory volume in 1 s (FEV1) over the double-blind phase. Secondary end-points included changes in forced vital capacity and pulmonary exacerbations. A significant improvement in FEV1 was seen over 26 weeks (p<0.001) and was apparent by 6 weeks, irrespective of concomitant recombinant human deoxyribonuclease (rhDNase) use. At 26 weeks, there was a significant improvement in FEV1 of 92.9 mL for subjects receiving mannitol compared with controls (change from baseline 118.9 mL (6.5%) versus 26.0 mL (2.4%); p<0.001). Improvements in FEV1 were maintained up to 52 weeks in the OL part of the study. There was a 35.4% reduction in the incidence of having an exacerbation on mannitol (p=0.045). The incidence of adverse events (AEs) was similar in both groups, although treatment-related AEs were higher in the mannitol compared with the control group. The most common mannitol-related AEs were cough, haemoptysis and pharyngolaryngeal pain. Mannitol showed sustained, clinically meaningful benefit in airway function in CF, irrespective of concomitant rhDNase use. Mannitol appears to have an acceptable safety profile for patients with CF.


Assuntos
Fibrose Cística/tratamento farmacológico , Inaladores de Pó Seco , Manitol/administração & dosagem , Administração por Inalação , Adolescente , Criança , Fibrose Cística/fisiopatologia , Desoxirribonucleases/uso terapêutico , Método Duplo-Cego , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Manitol/efeitos adversos , Proteínas Recombinantes/uso terapêutico , Capacidade Vital
16.
Hum Reprod ; 25(1): 265-74, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19897853

RESUMO

BACKGROUND: Obstetric haemorrhages have been reported to be increased after assisted reproduction technologies (ART) but the mechanisms involved are unclear. METHODS: This retrospective cohort study compared the prevalence of antepartum haemorrhage (APH), placenta praevia (PP), placental abruption (PA) and primary post-partum haemorrhage (PPH) in women with singleton births between 1991 and 2004 in Victoria Australia: 6730 after IVF/ICSI, 24 619 from the general population, 779 after gamete intrafallopian transfer (GIFT) and 2167 non-ART conceptions in infertile patients. Risk factors for haemorrhages in the IVF/ICSI group were examined by logistic regression. RESULTS: The IVF/ICSI group had more APH: 6.7 versus 3.6% (adjusted OR 2.0; 95% CI 1.8-2.3), PP: 2.6 versus 1.1% (2.3; 1.9-2.9), PA: 0.9 versus 0.4% (2.1; 1.4-3.0) and PPH: 11.1 versus 7.9% (1.3; 1.2-1.4) than the general population. APH, PP and PA were as frequent in the GIFT group as in the IVF/ICSI group, but were less frequent in the non-ART group. Within the IVF/ICSI group, fresh compared with frozen thawed embryo transfers (FET) was associated with more frequent APH (1.5; 1.2-1.8) and PA (2.1; 1.2-3.7) and the odds ratio increased with number of oocytes collected (1.02; 1.00-1.04). Endometriosis patients had more PP (1.7; 1.2-2.4) and PPH (1.3; 1.1-1.6) than those without endometriosis. FET in artificial cycles was associated with increased PPH (1.8; 1.3-2.6) compared with FET in natural cycles. CONCLUSIONS: Obstetric haemorrhages are more frequent with singleton births after IVF, ICSI and GIFT. The exploratory analysis of factors in the IVF/ICSI group, showing associations with fresh embryo transfers in stimulated cycles, endometriosis and hormone treatments, suggests that events around the time of implantation may be responsible and that suboptimal endometrial function is the critical mechanism.


Assuntos
Hemorragia/epidemiologia , Complicações do Trabalho de Parto/epidemiologia , Doenças Placentárias/epidemiologia , Técnicas de Reprodução Assistida , Feminino , Humanos , Gravidez , Prevalência , Estudos Retrospectivos , Fatores de Risco , Vitória/epidemiologia
17.
Hum Reprod ; 24(6): 1330-8, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19246467

RESUMO

BACKGROUND: First trimester screening (FTS) for Down syndrome combines measurement of nuchal translucency, free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein-A (PAPP-A). The aim of this study was to undertake a detailed analysis of FTS results in singleton pregnancies conceived using assisted reproductive technologies (ART) and non-ART pregnancies. METHODS: A record linkage study compared outcomes in 1739 ART-conceived and 50 253 naturally conceived pregnancies. RESULTS: Overall, significantly lower PAPP-A levels were detected in ART pregnancies (0.83 multiples of median, MoM) than in controls (1.00 MoM) (t-test P < 0.001). This difference remained after excluding complicated pregnancies. Analysis of factors affecting PAPP-A levels suggested fresh compared with frozen embryo transfers and use of artificial cycles compared with natural cycles for frozen transfers were associated with lower values. The adjusted odds ratio (AdjOR) for receiving a false-positive result was 1.71 (95% CI 1.44-2.04; P < 0.001) for ART pregnancies compared with non-ART pregnancies, and this leads to a higher AdjOR (1.24, 95% CI 1.03-1.49; P = 0.02) for having a chorionic villous sampling (CVS) or amniocentesis. CONCLUSIONS: ART pregnancies have reduced FTS PAPP-A levels leading to an increased likelihood of receiving a false-positive result and having a CVS/amniocentesis. Lower PAPP-A may reflect impairment of early implantation with some forms of ART.


Assuntos
Biomarcadores/sangue , Síndrome de Down/diagnóstico , Proteína Plasmática A Associada à Gravidez/metabolismo , Diagnóstico Pré-Natal/normas , Técnicas de Reprodução Assistida , Adolescente , Adulto , Amniocentese , Gonadotropina Coriônica Humana Subunidade beta/metabolismo , Amostra da Vilosidade Coriônica , Síndrome de Down/epidemiologia , Reações Falso-Positivas , Feminino , Coração/embriologia , Humanos , Pessoa de Meia-Idade , Medição da Translucência Nucal , Gravidez , Primeiro Trimestre da Gravidez/sangue , Fatores de Risco , Adulto Jovem
18.
BJOG ; 114(7): 812-8, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17501960

RESUMO

OBJECTIVE: The objective of this study was to follow up and evaluate the statewide first-trimester combined screening programme for Down syndrome and trisomy 18 at Genetic Health Services Victoria, Australia. DESIGN: Retrospective population cohort. SETTING: Maternal Serum Screening Laboratory records. SAMPLE: All women screened between February 2000 and June 2002 (16,153 pregnancies). METHODS: Screening results were matched to Victorian perinatal and birth defect data via record linkage, with an ascertainment of 96.8% of pregnancy outcomes. Manual follow up with health professionals increased ascertainment to more than 99%. MAIN OUTCOME MEASURES: Fetal Down syndrome or trisomy 18, and combined screen results, to calculate test characteristics. RESULTS: Using a risk threshold of 1 in 300 at time of ultrasound, the sensitivities for standard first-trimester combined screening and augmented 13-week combined screening for Down syndrome were 87.3 and 90.5% and the false-positive rates (FPR) were 4.1 and 3.9%, respectively. The sensitivity for trisomy 18 was 66.7% (10/15, 95% CI 42.8-90.5%) with a 0.4% FPR and 15.2% positive predictive value (1 in 250 risk threshold). CONCLUSIONS: The combined use of record linkage and manual follow-up techniques was effective in ascertaining more than 99% of pregnancy outcomes for calculations of accurate test characteristics of the combined screen. The sensitivity for Down syndrome at Genetic Health is comparable to similar populations. However, the sensitivity for trisomy 18 is lower than that elsewhere, which may reflect the overall low birth prevalence of trisomy 18 and associated small numbers in this particular cohort.


Assuntos
Cromossomos Humanos Par 18/genética , Síndrome de Down/diagnóstico , Testes Genéticos/normas , Diagnóstico Pré-Natal/normas , Trissomia/genética , Adulto , Estudos de Coortes , Feminino , Seguimentos , Testes Genéticos/métodos , Humanos , Idade Materna , Gravidez , Primeiro Trimestre da Gravidez , Diagnóstico Pré-Natal/métodos , Estudos Retrospectivos , Fatores de Risco , Sensibilidade e Especificidade , Vitória
19.
Biochem J ; 400(1): 43-52, 2006 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-16822232

RESUMO

The fungus Aspergillus niger is an industrial producer of pectin-degrading enzymes. The recent solving of the genomic sequence of A. niger allowed an inventory of the entire genome of the fungus for potential carbohydrate-degrading enzymes. By applying bioinformatics tools, 12 new genes, putatively encoding family 28 glycoside hydrolases, were identified. Seven of the newly discovered genes form a new gene group, which we show to encode exoacting pectinolytic glycoside hydrolases. This group includes four exo-polygalacturonan hydrolases (PGAX, PGXA, PGXB and PGXC) and three putative exo-rhamnogalacturonan hydrolases (RGXA, RGXB and RGXC). Biochemical identification using polygalacturonic acid and xylogalacturonan as substrates demonstrated that indeed PGXB and PGXC act as exo-polygalacturonases, whereas PGXA acts as an exo-xylogalacturonan hydrolase. The expression levels of all 21 genes were assessed by microarray analysis. The results from the present study demonstrate that exo-acting glycoside hydrolases play a prominent role in pectin degradation.


Assuntos
Aspergillus niger/enzimologia , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/metabolismo , Pectinas/metabolismo , Acetilesterase/genética , Acetilesterase/metabolismo , Sequência de Aminoácidos , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/genética , Carboidratos/farmacologia , DNA Fúngico/química , DNA Fúngico/genética , Proteínas Fúngicas/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Genoma Fúngico/genética , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Isoenzimas/genética , Isoenzimas/metabolismo , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Filogenia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
20.
J Obstet Gynaecol ; 24(6): 647-51, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16147604

RESUMO

This questionnaire-based study in Victoria, Australia, examined the responses of pregnant women, aged 37 years and over, to a question about what they expected prenatal testing (screening and/or diagnosis) for birth defects to tell them about their pregnancy. Content analysis showed that, of the 432 tested women, 61.3% mentioned Down syndrome, chromosomal abnormalities or trisomies. Women undergoing both screening and diagnosis were more likely than those having one or other test to mention Down syndrome (adjusted OR = 1.6, P = 0.06), having adjusted for age, marital status, education, residence and parity. Similarly, those from an English-speaking background were more likely to mention Down syndrome, etc. compared to women from a non-English-speaking background (adjusted OR = 3.5, P < 0.001). Down syndrome, a fundamental piece of information about prenatal tests, was not mentioned in nearly 40% of women's responses. This suggests that pregnant women need clearer information about prenatal testing, including the conditions that might be detected.


Assuntos
Síndrome de Down/diagnóstico , Educação de Pacientes como Assunto , Diagnóstico Pré-Natal , Análise de Variância , Austrália , Feminino , Humanos , Idioma , Gravidez , Inquéritos e Questionários
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