Letteratura scientifica selezionata sul tema "Fetal size/growth"
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Articoli di riviste sul tema "Fetal size/growth"
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Harrington, Kevin, e Stuart Campbell. "Fetal size and growth". Current Opinion in Obstetrics and Gynecology 5, n. 2 (aprile 1993): 186???194. http://dx.doi.org/10.1097/00001703-199304000-00004.
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Kirchengast, Sylvia, e Beda Hartmann. "Association patterns of fetal head dimensions, postcranial body growth and neonatal size". Anthropologischer Anzeiger 77, n. 2 (30 aprile 2020): 173–81. http://dx.doi.org/10.1127/anthranz/2020/1137.
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Merialdi, M., L. E. Caulfield, N. Zavaleta, A. Figueroa, K. A. Costigan, F. Dominici e J. A. Dipietro. "Fetal growth in Peru: comparisons with international fetal size charts and implications for fetal growth assessment". Ultrasound in Obstetrics and Gynecology 26, n. 2 (22 luglio 2005): 123–28. http://dx.doi.org/10.1002/uog.1954.
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Spencer, J. A. D., T. C. Chang, S. C. Robson e S. Gallivan. "Fetal size and growth in Bangladeshi pregnancies". Ultrasound in Obstetrics and Gynecology 5, n. 5 (1 maggio 1995): 313–17. http://dx.doi.org/10.1046/j.1469-0705.1995.05050313.x.
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Frusca, T., S. Parolini, A. Dall'Asta, W. A. Hassan, A. Vitulo, A. Gillett, D. Pasupathy e C. C. Lees. "Fetal size and growth velocity in chronic hypertension". Pregnancy Hypertension 10 (ottobre 2017): 101–6. http://dx.doi.org/10.1016/j.preghy.2017.06.007.
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McCarthy, Elizabeth A., e Susan P. Walker. "International fetal growth standards: one size fits all". Lancet 384, n. 9946 (settembre 2014): 835–36. http://dx.doi.org/10.1016/s0140-6736(14)61416-1.
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Friedrich, M. J. "International Standards for Newborn Size and Fetal Growth". JAMA 312, n. 15 (15 ottobre 2014): 1503. http://dx.doi.org/10.1001/jama.2014.13252.
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Keshavarz, Elham, Marjan Rustazade Sheikhyusefi, Ensi Khalili Pouya, Masoumeh Mirzamoradi, Mehdi Khazaei, Yashar Moharamzad e Morteza Sanei Taheri. "Association Between Fetal Thymus Size and Intrauterine Growth Restriction". Journal of Diagnostic Medical Sonography 38, n. 2 (14 dicembre 2021): 120–26. http://dx.doi.org/10.1177/87564793211054747.
Testo completoAbstract (sommario):
Objective: The objective of this study was to evaluate the association between reduced fetal thymus size and intrauterine growth restriction (IUGR). This study was devised to determine the association between thymus size and any abnormal Doppler indices within the fetal umbilical artery (UA), as well as the middle cerebral artery (MCA). Materials and Methods: Forty-six pregnancies between 20 and 38 weeks of gestation with IUGR and 46 normal pregnancies within similar gestational age (GA) range were included. The transverse diameter of fetal thymus was measured. In the IUGR group, the fetal umbilical artery (UA) and middle cerebral artery (MCA) Doppler flow velocities were recorded. Results: The mean GA of fetuses with IUGR (33.5 weeks) was higher than control group (30.3 weeks). To adjust for the effect of GA, analysis of covariance (ANCOVA) was performed. The adjusted mean thymus diameters were 19.02 mm in IUGR and 21.25 within the control group (mean difference = 2.23 mm; P = .02). The mean (±SD) thymus size in 16 fetuses, with abnormal Doppler findings, was significantly lower than in the group with normal Doppler findings, 17.45 (±2.50) vs 22.02 (±5.39) mm; P < .001. Conclusion: IUGR may be associated with reduced fetal thymus size, especially when coupled with abnormal Doppler findings. The thymus size in a group of IUGR fetuses, with abnormal Doppler findings, was smaller than IUGR fetuses, with normal Doppler findings.
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Fulford, A. J. C., S. E. Moore, S. E. Arifeen, L. Å. Persson, L. M. Neufeld, Y. Wagatsuma e A. M. Prentice. "Disproportionate early fetal growth predicts postnatal thymic size in humans". Journal of Developmental Origins of Health and Disease 4, n. 3 (7 marzo 2013): 223–31. http://dx.doi.org/10.1017/s2040174413000044.
Testo completoAbstract (sommario):
Prenatal events can affect neonatal thymus size and adult immune function. The causal insults are unknown, although fetal nutrient restriction is suspected. We used ultrasound at three time points during pregnancy (14, 19 and 30 weeks) to measure the growth of six fetal dimensions in rural Bangladeshi women participating in the Maternal and Infant Nutrition Interventions, Matlab study. Postnatal ultrasound was used to calculate thymic index (TI) at birth, 2, 6 and 12 m. Of the 3267 women recruited, 2861 participated by providing data at least at one fetal biometry and one TI time point. Patterns of fetal growth were summarized using principal components calculated from fetal dimensionz-scores. Random effects regression, controlling for infant size and season of measurement were used to relate these patterns to TI. We found that smaller leg length relative to head circumference, characteristic of head-sparing growth restriction, was predictive of lower TI. This association was significant at all time points but strongest in earlier pregnancy. Each standard deviation increase in leg–head proportion was associated with an increase in TI of ∼5%. We conclude that growth patterns typical of poor fetal nutrition are associated with poor thymic development. The greater strength of this association in the first trimester is consistent with a period of vulnerability during the early ontogeny of the thymus and suggests that preventative intervention would need to be given in early pregnancy.
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Schwartz, Nadav, Mary Sammel, Hayley Quant, Rita Leite e Samuel Parry. "379: Early placental size helps predict fetal growth restriction". American Journal of Obstetrics and Gynecology 208, n. 1 (gennaio 2013): S166—S167. http://dx.doi.org/10.1016/j.ajog.2012.10.544.
Testo completoTesi sul tema "Fetal size/growth"
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Westerway, Susan Lyn Campbell. "Ultrasonic assessment of fetal size and growth". University of Sydney, 2006. http://hdl.handle.net/2123/2626.
Testo completoAbstract (sommario):
Doctor of Philosophy (Medicine)This work investigates a number of issues. Firstly it examines ultrasonic fetal biometry, the parameters and techniques for accurate measuring and reviews the procedure adopted for graph formation and application of regression analysis for a mathematical model to describe the relationship between fetal size and weeks of gestation. Next it establishes new Australian fetal measurement charts for the crown rump length, head circumference and abdominal circumference, based on an Australian population, to replace the charts currently in use that are over 20 years old and relate to middle class white American and British women. The new graphs, along with previous work completed by the author in 1999 on the BPD, OFD femur and humerus length, were subsequently accepted by the Australasian Society for Ultrasound in Medicine (ASUM) in 2001 as the new Australian standard for ultrasonic fetal measurements. The accuracy of first trimester ultrasound dating is also investigated, displaying the variations seen in the crown-rump length due to fetal flexion and the implications of inaccurate measuring. The third study examines inter- and intra-sonographer ultrasonic fetal measurement reproducibility in the final 6 weeks of pregnancy. The study highlights the importance of sonographer competence, standardised measuring protocols, image planes and reference charts, particularly for patients undergoing ultrasound examinations for fetal growth assessment at different practices. The fourth study looks at the incidence of fetal macrosomia and birth complications in Chinese women and Caucasian women in two time periods, 1992 and 1999/2000. The results showed a rise in macrosomic babies born to Chinese immigrants from 4% of total Chinese births in 1992 to 9.8% in 1999/2000. There was also a rise in the rate of macrosomia among Caucasian women with respective rates of 11 and 14% for the same periods. The incidence of post partum haemorrhage increased significantly over this time in both Chinese immigrant and Caucasian women. Interventions declined in all Caucasian birth-weight ranges whilst interventions for Chinese births remained stable except between 3500grams and 4000grams, where interventions rose from 35.7% to 60.5%. Fetal macrosomia is a complication of pregnancy that is increasing in incidence. One of the causes of fetal overgrowth is uncontrolled gestational diabetes mellitus and so if women thus diagnosed are closely monitored, the risks of a macrosomic baby and associated birth complications may be reduced. The final study examines the effect of gestational diabetes mellitus (GDM) on fetal growth. GDM is a complication of mid to late pregnancy caused by glucose intolerance. In the Australian population up to 8% of all pregnancies can be affected. In the Australian Chinese community the GDM rate is as high as 15% compared with 4% in Caucasian women. The risks to the fetus as a result of GDM include increased perinatal mortality, large for gestational dates, macrosomia and prematurity. The aim of this study was to determine whether the fetuses of women diagnosed with GDM were significantly larger for dates for any of the commonly ultrasonically measured fetal parameters, than in the general pregnant population. The results show that if the glycaemic levels are properly controlled, fetal size should not be compromised. The abdominal circumference measurement appears to be the important marker for fetal macrosomia, particularly in the Chinese population. The study also assessed fetal weight gain from 36 weeks gestation to term in Caucasian women with GDM and Chinese pregnancies both with and without GDM. No statistically significant difference was seen in daily weight gain between the groups investigated.
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Westerway, Susan Lyn Campbell. "Ultrasonic assessment of fetal size and growth". Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/2626.
Testo completoAbstract (sommario):
This work investigates a number of issues. Firstly it examines ultrasonic fetal biometry, the parameters and techniques for accurate measuring and reviews the procedure adopted for graph formation and application of regression analysis for a mathematical model to describe the relationship between fetal size and weeks of gestation. Next it establishes new Australian fetal measurement charts for the crown rump length, head circumference and abdominal circumference, based on an Australian population, to replace the charts currently in use that are over 20 years old and relate to middle class white American and British women. The new graphs, along with previous work completed by the author in 1999 on the BPD, OFD femur and humerus length, were subsequently accepted by the Australasian Society for Ultrasound in Medicine (ASUM) in 2001 as the new Australian standard for ultrasonic fetal measurements. The accuracy of first trimester ultrasound dating is also investigated, displaying the variations seen in the crown-rump length due to fetal flexion and the implications of inaccurate measuring. The third study examines inter- and intra-sonographer ultrasonic fetal measurement reproducibility in the final 6 weeks of pregnancy. The study highlights the importance of sonographer competence, standardised measuring protocols, image planes and reference charts, particularly for patients undergoing ultrasound examinations for fetal growth assessment at different practices. The fourth study looks at the incidence of fetal macrosomia and birth complications in Chinese women and Caucasian women in two time periods, 1992 and 1999/2000. The results showed a rise in macrosomic babies born to Chinese immigrants from 4% of total Chinese births in 1992 to 9.8% in 1999/2000. There was also a rise in the rate of macrosomia among Caucasian women with respective rates of 11 and 14% for the same periods. The incidence of post partum haemorrhage increased significantly over this time in both Chinese immigrant and Caucasian women. Interventions declined in all Caucasian birth-weight ranges whilst interventions for Chinese births remained stable except between 3500grams and 4000grams, where interventions rose from 35.7% to 60.5%. Fetal macrosomia is a complication of pregnancy that is increasing in incidence. One of the causes of fetal overgrowth is uncontrolled gestational diabetes mellitus and so if women thus diagnosed are closely monitored, the risks of a macrosomic baby and associated birth complications may be reduced. The final study examines the effect of gestational diabetes mellitus (GDM) on fetal growth. GDM is a complication of mid to late pregnancy caused by glucose intolerance. In the Australian population up to 8% of all pregnancies can be affected. In the Australian Chinese community the GDM rate is as high as 15% compared with 4% in Caucasian women. The risks to the fetus as a result of GDM include increased perinatal mortality, large for gestational dates, macrosomia and prematurity. The aim of this study was to determine whether the fetuses of women diagnosed with GDM were significantly larger for dates for any of the commonly ultrasonically measured fetal parameters, than in the general pregnant population. The results show that if the glycaemic levels are properly controlled, fetal size should not be compromised. The abdominal circumference measurement appears to be the important marker for fetal macrosomia, particularly in the Chinese population. The study also assessed fetal weight gain from 36 weeks gestation to term in Caucasian women with GDM and Chinese pregnancies both with and without GDM. No statistically significant difference was seen in daily weight gain between the groups investigated.
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Baird, Janis. "Birth size, blood pressure and glucose tolerance in twins : testing the fetal origins hypothesis". Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341624.
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Vaughn, Mathew Alan. "Characterization of intra-litter variation on myogenic development and myogenic progenitor cell response to growth promoting stimuli". Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34595.
Testo completoAbstract (sommario):
Doctor of PhilosophyDepartment of Animal Sciences and Industry
John M. Gonzalez
This series of studies focuses on the impact of intra-litter variation on fetal myogenesis, and the ability of porcine progenitor cells to respond to growth promoting stimuli. In study 1, the smallest (SM), median (ME), and largest (LG) male fetuses from each litter were selected for muscle morphometric analysis from gilts at d-60 ± 2 and 95 ± 2 of gestation. On d-60 and 95 of gestation LG fetuses had greater whole muscle cross-sectional area (CSA) than ME and SM fetuses, and ME fetuses had greater whole muscle CSA than SM fetuses. Indicating that SM and ME fetuses are on a delayed trajectory for myogenesis compared to LG fetuses. At d-60 the advanced trajectory of LG compared to ME fetuses was due to increased development of secondary muscle fibers; whereas, the advanced myogenic development of LG and ME fetuses compared to SM fetuses was due to the presence of fewer primary and secondary muscle fibers. At d-95 of gestation the advanced myogenic development of LG and ME was due to increased hypertrophy of secondary muscle fibers. For study 2, porcine fetal myoblasts (PFM) were isolated from SM, ME, and LG fetuses from d-60 ± 2 of gestation fetuses and for study 3, porcine satellite cells (PSC) were isolated from the piglet nearest the average body weight of the litter. Both myogenic cell types were utilized to evaluate effects of porcine plasma on proliferation, differentiation, and indications of protein synthesis. For the proliferation assay, cells were exposed to one of three treatments: high serum which consisted high-glucose Dulbecco's Modified Eagle Medium supplemented with 10% (vol/vol) fetal bovine serum, 2% (vol/vol) porcine serum, 100 U penicillan/mL, 100 µg of strepmycin/mL, and 20 µg of gentamicin/mL (HS), low serum which consisted of HS without 10% FBS (LS), and LS supplemented with 10% (wt/vol) porcine plasma (PP). Treatments for the differentiation and protein synthesis assays consisted of either HS or LS media that either contained porcine plasma at 10% (wt/vol; PPP) or 0% (wt/vol; PPN). The HS-PFM had a greater proliferation rate compared to the LS and PP-PFM, and PP-PFM had a greater proliferation rate compared to LS-PFM. The LG fetuses’ PFM had a reduced proliferation rate compared to SM and ME fetuses’ PFM, which were similar. The PPP-PFM had a decreased myotube diameter compared to PPN-PFM. Small fetuses’ PFM had a greater myotube diameter compared to ME and LG fetuses’ PFM, and ME fetuses’ PFM had a greater myotube diameter compared to LG fetuses’ PFM. The proliferation rate of PP-PSC was decreased compared to the HS- and LS-PSC, and HS-PSC had a greater proliferation rate compared to LS-PSC. The PPP-PSC had greater differentiation capacity and myotube diameter than PPN-PSC. In conjunction these results indicate divergent myogenic development among different fetal sizes within a litter and suggest that porcine plasma supplementation stimulates myogenic progenitor cell activity in an age specific manner.
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Bennini, Junior João Renato 1978. "Estimativa do peso do recem-nascido por meio de medidas ultrassonograficas bidimensionais e do volume da coxa fetal". [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/313463.
Testo completoAbstract (sommario):
Orientadores: Cleisson Fabio Andrioli Peralta, Ricardo BariniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-11-27T11:44:05Z (GMT). No. of bitstreams: 1 BenniniJunior_JoaoRenato_M.pdf: 1809698 bytes, checksum: 399e6ab502353af527e35953428d5e09 (MD5) Previous issue date: 2009
Resumo: Introdução: Alguns estudos demonstram que a predição do peso fetal usando a volumetria dos membros fetais é mais precisa do que quando se usam medidas bidimensionais (2D). Até hoje, somente o método multiplanar foi utilizado para a volumetria dos membros fetais. Desta forma, a utilidade do método rotacional (VOCAL®) para este fim nunca foi testada. Objetivos: Avaliar as variabilidades intra e interobservadores e a concordância entre as medidas do volume da coxa fetal realizadas com os métodos multiplanar e VOCAL®. Comparar as acurácias das fórmulas com medidas do volume da coxa fetal com as acurácias das fórmulas com medidas 2D. Comparar as acurácias das fórmulas deste estudo com as acurácias das fórmulas já publicadas. Métodos: 210 pacientes foram avaliadas, formando um grupo para gerar as fórmulas (n = 150) e um grupo para validá-las (n = 60). Os pacientes utilizados para gerar as fórmulas também foram utilizados para avaliar as variabilidades intra e interobservadores e a concordância entre as medidas realizadas pelos métodos multiplanar e VOCAL®. Foram utilizadas análises de regressão polinomial para criar uma equação com medidas 2D, uma com o volume da coxa fetal medido pelo método multiplanar (CoxaM) e uma com o volume da coxa fetal medido pelo método VOCAL® (CoxaV). Utilizaram-se testes t de Student pareados para comparar as acurácias das equações deste estudo com as acurácias das fórmulas já publicadas. Foram utilizadas análises proporcionais de Bland e Altman para avaliar as variabilidades intra e interobservadores e a concordância entre as medidas realizadas pelos métodos multiplanar e VOCAL®. Resultados: A diferença média percentual entre as medidas pelos métodos multiplanar e VOCAL® foi de -0,04 com limites de concordância de 95% de -8,17 e 8,09. A diferença média percentual e os limites de concordância de 95% entre as medidas na avaliação das variabilidades intra e interobservadores foram -1,10 (-7,67 to 5,47) e 0,61 (-7,68 to 8,91) para o método VOCAL® e 1,03 (-6,35 to 8,41) e -0,68 (-11,42 to 10,06) para o multiplanar. As melhores fórmulas para cálculo do peso fetal estimado (PFE) foram: PFE = -562.824 + 11.962 x CA x CF + 0,009 x DBP² x CA² (CA: circunferência abdominal; CF: comprimento femoral; DBP: diâmetro biparietal); PFE = 1033.286 + 12.733 x CoxaM; PFE = 1025.383 + 12.775 x CoxaV. Tanto no grupo que gerou as fórmulas como no grupo utilizado para validá-las não houve diferença significativa entre as acurácias das fórmulas com medidas 2D ou tridimensionais (3D). Quando aplicadas nas pacientes deste estudo, as acurácias das fórmulas 2D e 3D já publicadas foram significativamente piores dos que as das novas fórmulas. Conclusões: Os métodos VOCAL® e multiplanar são intercambiáveis para a volumetria da coxa fetal. Possivelmente as maiores fontes de discrepâncias na estimativa do peso fetal são as diferenças fenotípicas entre as pacientes utilizadas para criar as fórmulas. Os dados deste estudo reforçam a necessidade de fórmulas específicas para cada população, independentemente do uso de medidas 2D ou 3D.
Abstract: Introduction: Some authors have demonstrated that the prediction of birth weight using fetal limb volumetry is more precise than with two-dimensional ultrasound (2DUS). To date, only the multiplanar method has been used for fetal limb volumetry, so the usefulness of the rotational technique (VOCALTM - Virtual Organ Computer- aided AnaLysis) for this purpose has never been tested. Objectives: To evaluate the repeatability, reproducibility and agreement of measurements performed with multiplanar and VOCALTM techniques for total fetal thigh volumetry. To compare the accuracies of birth-weight-predicting models with total fetal thigh volumetry with models derived from 2DUS parameters. To compare the performances of our new formulas with those of previously published equations. Methods: 210 patients were prospectively evaluated to compose a formula-generating group (n = 150) and a prospective-validation group (n = 60). The patients of the formula-generating group were also used to evaluate the repeatability, reproducibility and the agreement of the measurements of multiplanar and VOCALTM techiniques for fetal thigh volumetry. Polynomial regression analysis was performed in the formula-generating group to generate one equation with 2DUS measurements, one with fetal thigh volume measured by the multiplanar technique (ThiM) and one with fetal thigh volume obtained by the VOCALTM method (ThiV). Paired samples t-tests were used to compare the accuracies of our equations with those of previously published 2D and three-dimensional (3D) equations. Proportionate Bland and Altman analyses were performed to determine the agreement between the two methods and to evaluate intra- and inter-observer variability. Results: The mean percentage difference between measurements performed with the VOCALTM and multiplanar techniques was -0.04 and the 95% limits of agreement were -8.17 and 8.09. The mean percentage difference and 95% limits of agreement between paired measurements in the assessment of intra- and inter-observer variability were -1.10 (-7.67 to 5.47) and 0.61 (-7.68 to 8.91) for the VOCALTM technique and 1.03 (-6.35 to 8.41) and -0.68 (-11.42 to 10.06) for the multiplanar method. The formulas with the best fit for the prediction of birth weight (EFW) were: EFW = -562.824 + 11.962 x AC x FL + 0.009 x BPD² x AC² (AC: abdominal circumference; FL: femur length; BPD: biparietal diameter); EFW = 1033.286 + 12.733 x ThiM; EFW = 1025.383 + 12.775 x ThiV. For both the formula-generating and the rospective-validation groups, there was no significant difference between the accuracies of the new 2DUS and 3DUS models. When applied to our population, the accuracies of previously published 2DUS and 3DUS formulas were significantly worse than our models. Conclusions: The VOCALTM and multiplanar techniques can be used interchangeably for total fetal thigh volumetry. We believe that the greatest sources of discrepancies in estimation of birth weight are the phenotypic differences among patients used to create each of the formulas mentioned in this study. Our data reinforce the need for customized birth weight prediction formulas, regardless of whether 2DUS or 3DUS measurements are employed.
Mestrado
Tocoginecologia
Mestre em Tocoginecologia
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Dreyer, Carlien. "Fruit set and fruit size studies on ‘Forelle’ and ‘Abate Fetel’ pear (Pyrus communis L.)". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79870.
Testo completoAbstract (sommario):
Thesis (MScAgric)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Maintaining constant high yields in „Abate Fetel‟ and „Forelle‟ orchards in South Africa is challenging. Improving productivity in these orchards could be achieved by increasing fruit set and fruit size. Fruit size is an important marketing and quality parameter and has a significant effect on the economic value of fruit. Various protocols to improve fruit set are used by South African producers but these are not well researched. We therefore evaluated different combinations of plant growth regulators including gibberellic acid (GA3), gibberellins 4+7 (GA4+7), GA4+7 combined with 6-benzyladenine (6-BA), aminoethoxyvinylglycine (AVG) and prohexadione-calcium (P-Ca) in combination with trunk girdling during flowering on „Forelle‟ and „Abate Fetel‟ to determine the best fruit set strategy. All applied growth regulators improved fruit set relative to an untreated control over two consecutive seasons, but GA3 and P-Ca reduced return bloom and AVG resulted in smaller fruit size relative to the other treatments. The application of synthetic cytokinins are believed to enhance fruit size by stimulating and extending the cell division period in fruit when applied at the correct stage of fruit growth. In addition, combination of P-Ca with GA4+7 was used successfully on Japanese pear (Pyrus pyrifolia Nakai) and „Bing‟ sweet cherry to improve fruit size. This combination of GA4+7 and P-Ca was evaluated and combined with 6-BA treatments on European pear (Pyrus communis L.) cultivars, Forelle and Abate Fetel, to see if a similar effect on fruit size could be achieved under South African growing conditions. On both „Forelle‟ and „Abate Fetel‟ the combination of GA4+7 and P-Ca increased fruit size, but was more pronounced in „Abate Fetel‟. Growth regulators N-phenyl-N‟ -1,2,3-thiadiazol-5-ylurea (TDZ), N (2-chloro-4-pyridyl)-N‟ -phenylurea (CPPU), 6-BA and 2,4-dichlorophenoxyacetic acid (2,4-D) successfully increased fruit size in pear cultivars Coscia and Spadona in Israel. These growth regulators were applied to „Forelle‟ and „Abate Fetel‟ to determine if a similar effect could be achieved. None of the synthetic cytokinins applied had a significant effect on increasing fruit size in these two cultivars over two consecutive seasons although 6-BA increased return bloom and 2,4-D application resulted in increased fruit set. The stage when the cell division period in „Forelle‟ and „Abate Fetel‟ ends was also determined as 34 and 45 days after full bloom respectively, which can be used in the future to better plan the timing of fruit size enhancement treatments. Based on results from various fruit set and fruit size improvement trials, it can be recommended to use GA4+7 or AVG to increase fruit set on „Forelle‟ and „Abate Fetel‟, depending on the fruit set history of the orchard. Results from fruit size improvement trials were variable, and emphasises the fact that a balance between yield and fruit size must be determined for an orchard to achieve good fruit size and maximum return.
AFRIKAANSE OPSOMMING: Die handhawing van konstante, hoë opbrengste in „Abate Fetel‟ en „Forelle‟ boorde in Suid-Afrika is 'n uitdaging. Produktiwiteit in hierdie boorde kan verhoog word deur vrugset en vruggrootte te verbeter. Vruggrootte is 'n belangrike bemarkings- en kwaliteitsparameter en het 'n betekenisvolle effek op die ekonomiese waarde van vrugte. 'n Verskeidenheid protokolle om vrugset te verbeter word deur Suid-Afrikaanse produsente gevolg, maar hierdie protokolle is nog nie goed nagevors nie. Verskillende kombinasies van plantgroeireguleerders insluitend gibberelliensuur (GA3), gibberellien 4+7 (GA4+7), GA4+7 in kombinasie met 6-bensieladenien (6-BA), aminoetoksievinielglisien (AVG) en prohexadioon-kalsium (P-Ca) in kombinasie met stamringelering is aan „Forelle‟ en „Abate Fetel‟ bome gedurende blomtyd toegedien om die beste vrugsetstrategie te bepaal. Alle plantgroeireguleerdes wat toegedien is het vrugset verbeter relatief tot 'n onbehandelde kontrole oor twee opeenvolgende seisoene, maar GA3 en P-Ca het die aantal blomme in die daaropvolgende seisoen verlaag en AVG het kleiner vruggrootte gelewer relatief tot alle ander behandelings. Dit is wel bekend dat die toediening van sintetiese sitokiniene vruggrootte verbeter deur die stimulering en bevordering van seldeling in vrugte wanneer dit in die regte groeifase toegedien word. Die kombinasie van P-Ca en GA4+7 was suksesvol om vruggrootte te verbeter toe dit aan Japanese pere (Pyrus pyrifolia Nakai) en „Bing‟ kersies toegedien is. Hierdie kombinasie van GA4+7 en P-Ca is geëvalueer en gekombineer met 6-BA-behandelings op die Europese peer (Pyrus communis L.) kultivars, Forelle en Abate Fetel, om te bepaal of dieselfde effek op vruggrootte bereik kan word onder Suid-Afrikaanse groei kondisies. Op beide „Forelle‟ en „Abate Fetel‟ het die kombinasies van GA4+7 en P-Ca vruggrootte verbeter, maar dit was meer opmerklik in die geval van „Abate Fetel‟. Die groeireguleerders N-feniel-N‟ -1,2,3-thiadiazol-5-ylurea (TDZ), N (2-chloro-4-piridiel)-N‟ -fenielurea (CPPU), 6-BA en 2,4- dichloorfenoksieasynsuur (2,4-D) het vruggrootte verbeter in „Coscia‟ en „Spadona‟ pere in Israel. Hierdie plantgroeireguleerders is toegedien aan „Forelle‟ en „Abate Fetel‟ om vas te stel of dieselfde effek verkry kon word. Nie enige van die sintetiese sitokiniene wat toegedien is het 'n betekenisvolle effek op die verbetering van vruggrootte in hierdie twee kultivars oor twee opeenvolgende seisoene getoon nie, alhoewel 6-BA die verbetering van blom in die daaropvolgende seisoen tot gevolg gehad en 2,4-D vrugset verbeter het. Die stadium waar seldeling in „Forelle‟ en „Abate Fetel‟ eindig is vasgestel as 34 en 45 dae na volblom, onderskeidelik, wat in die toekoms gebruik kan word om die beplanning en tydsberekening van vruggrootte behandelings te verbeter. Na verskeie vrugset en vruggroote verbeterings proewe, kan aanbeveel word dat GA4+7 of AVG gebruik kan word om vrugset in „Forelle‟ en „Abate Fetel‟ te verbeter, afhangende van die vrugset geskiedenis van die boord. Resultate van vruggrootte verbeterings proewe het gevarieër en beklemtoon net weer die feit dat 'n balans tussen opbrengs en vruggrootte bepaal moet word om optimale vruggrootte te handhaaf en so hoë winste te verseker.
SAAPPA
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Hewitt, Damien Phillip. "Impact of glucocorticoids on placental growth and vascularisation". University of Western Australia. School of Anatomy and Human Biology, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0195.
Testo completoAbstract (sommario):
[Truncated abstract] Glucocorticoids are critical for the maturation of the fetus late in pregnancy. Indeed, clinical administration of glucocorticoids is used to accelerate fetal lung maturation in mothers at risk of pre-term delivery. Increased glucocorticoid exposure, however, can have detrimental effects on fetal and placental growth and increase the risk of disease in later life. Many studies have focused on the effect of an increase in the transplacental passage of glucocorticoids on both fetal growth and subsequent postnatal development. But there is a growing body of evidence to suggest that the impact of glucocorticoids on fetal growth is mediated, in part, via their direct effects on the placenta . . . Overall, these studies quantify the labyrinth zone-specific increases in placental expression of PPARG and VEGF in association with a marked increase in vascularisation observed near term. Furthermore, this study demonstrates for the first time that these increases in gene expression are prevented by maternal dexamethasone treatment which also inhibits growth of the fetal capillary network. Elevated expression of SFRP4 in the regressing basal zone late in gestation and in both placental zones after dexamethasone-induced placental growth restriction is consistent with a role for SFRP4 in glucocorticoid-mediated inhibition of wnt signalling. Collectively, the data presented in this thesis show that glucocorticoid inhibition of fetal growth is mediated in large part via effects on the placenta, specifically through inhibition of signals that promote proliferation and vascularisation.
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Mariet, Anne-Sophie. "Influence de l’exposition au bruit et à la pollution de l’air en milieu urbain sur la survenue de complications et d’issues défavorables de la grossesse". Thesis, Bourgogne Franche-Comté, 2020. https://nuxeo.u-bourgogne.fr/nuxeo/site/esupversions/b8bd098d-4e78-4f44-b87c-01a65906c7a1.
Testo completoAbstract (sommario):
La grossesse constitue une période de vulnérabilité où la survenue de complications et d’issues défavorables de la grossesse (CIDG) peut avoir des conséquences majeures sur le devenir de la mère et/ou du nouveau-né. De multiples facteurs en sont à l’origine. Cependant, il reste encore une part non expliquée de CIDG, pour laquelle l’environnement est suspecté de jouer un rôle.Ce travail de thèse est inclus dans le programme PreCEE (Pregnancy Combined Environmental Exposure) et a pour objectif d’étudier l’influence des expositions environnementales aux pollutions sonore et atmosphérique sur la survenue de CIDG, plus particulièrement de troubles de la croissance fœtale et de troubles hypertensifs de la grossesse. Ont été incluses toutes les grossesses de femmes majeures résidant à Besançon ou dans l’unité urbaine de Dijon et ayant accouché au CHU de Besançon ou au CHU Dijon-Bourgogne entre 2005 et 2009, soit plus de 10 000 grossesses. Les caractéristiques socio-démographiques, médicales et médico-obstétricales ont été recueillies à partir des dossiers obstétricaux informatisés et papier. Les niveaux d’exposition au bruit et à la pollution atmosphérique (dioxyde d’azote (NO2) et particules fines (PM10)) ont été modélisés au domicile de la mère selon des fenêtres spatiales et temporelles différentes.Les résultats montrent que l’exposition au bruit n’est pas associée à la survenue de troubles hypertensifs de la grossesse ou de troubles de la croissance foetale, chez les grossesses uniques. L’exposition aux PM10 est associée à la survenue de troubles de la croissance fœtale chez les grossesses uniques. Cette association n’est pas modifiée par la prise en compte de l’exposition au bruit. Enfin, chez les grossesses multiples, l’exposition au NO2 est associée à la survenue de troubles de la croissance fœtalePregnancy is a period of vulnerability where the occurrence of adverse pregnancy outcomes (APO) can have major consequences on the future of the mother and/or the newborn. Multiple factors are responsible for this. However, there is still an unexplained part of APO, for which the environment is suspected to play a role.This PhD thesis is included in the PreCEE (Pregnancy Combined Environmental Exposure) program and aimed to study the influence of environmental exposures to noise and air pollution on the occurrence of APO, more particularly on fetal growth disorders and hypertensive disorders of pregnancy (HDP). All pregnancies of adult women living in Besançon or in the urban unit of Dijon and who gave birth to the Besançon University Hospital or the Dijon-Burgundy University Hospital between 2005 and 2009 were included, i.e. more than 10,000 pregnancies. The socio-demographic, medical and medico-obstetrical characteristics were collected from computerized and paper obstetric records. The levels of exposure to noise and air pollution (nitrogen dioxide (NO2) and fine particles (PM10)) were modeled at the mother's home according to several spatial and temporal windows.Results show that noise exposure is not associated with the occurrence of HDP or fetal growth disorders in single pregnancies. Exposure to PM10 is associated with fetal growth disorders. This association is not changed by taking noise exposure into account. Finally, in multiple pregnancies, exposure to NO2 is associated with fetal growth disorders
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Cavallin, Mara. "Physiopathologie moléculaire et cellulaire des anomalies du développement du cortex cérébral : le syndrome d'Aicardi WDR81 mutations cause extreme microcephaly and impair mitotic progression in human fibroblasts and Drosophila neural stem cells TLE1, a key player in neurogenesis, a new candidate gene for autosomal recessive postnatal microcephaly Mutations in TBR1 gene leads to cortical malformations and intellectual disability Aicardi syndrome: Exome, genome and RNA-sequencing of a large cohort of 19 patients failed to detect the genetic cause Recurrent RTTN mutation leading to severe microcephaly, polymicrogyria and growth restriction Recurrent KIF2A mutations are responsible for classic lissencephaly Recurrent KIF5C mutation leading to frontal pachygyria without microcephaly Rare ACTG1 variants in fetal microlissencephaly De novo TUBB2B mutation causes fetal akinesia deformation sequence with microlissencephaly: An unusual presentation of tubulinopathy A novel recurrent LIS1 splice site mutation in classic lissencephaly Further refinement of COL4A1 and COL4A2 related cortical malformations Prenatal and postnatal presentations of corpus callosum agenesis with polymicrogyria caused By EGP5 mutation Delineating FOXG1 syndrome from congenital microcephaly to hyperkinetic encephalopathy Delineating FOXG1 syndrome: From congenital microcephaly to hyperkinetic encephalopathy". Thesis, Sorbonne Paris Cité, 2019. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2213&f=18201.
Testo completoAbstract (sommario):
Les malformations du cortex cérébral (MDC) représentent une cause importante de handicap et d'épilepsie pharmaco-résistante. Le séquençage à haut débit a permis une amélioration considérable de l'identification des bases moléculaires des MDC non syndromiques. Toutefois, certaines formes, notamment les MDC complexes, demeurent inexpliquées. Mon projet de thèse a pour objectif de progresser dans la compréhension des MDC complexes en utilisant deux modèles : les microlissencéphalies (MLIS) et le syndrome d'Aicardi (AIC), une forme syndromique particulière associant des malformations de l'oeil et du cerveau uniquement rapporté chez les filles. L'étude par séquençage d'exome en trios de 16 familles MLIS m'a permis d'identifier et de caractériser un nouveau gène, WDR81, impliqué dans le cycle cellulaire. Par la même stratégie, j'ai pu identifier un variant homozygote pathogène dans TLE1, un partenaire majeur de FOXG1 dans la balance prolifération/différenciation de progéniteurs neuronaux, dans une famille consanguine de microcéphalie postnatale dont le phénotype est proche du syndrome FOXG1. En parallèle, mes travaux ont permis de préciser les spectres phénotypiques associés à RTTN, EPG5, COL4A1, COL4A2, TBR1, KIF5C, KIF2A et FOXG1. La deuxième partie de mon projet avait pour objet l'identification des bases moléculaires du syndrome d'Aicardi à partir d'une cohorte internationale de 19 patientes. Après avoir exclu un biais d'inactivation du chromosome X et la présence de microremaniements chromosomiques, j'ai réalisé un séquençage d'exome en trio. Aucun variant récurrent n'a été retrouvé dans les séquences codantes. Dans un second temps, j'ai testé une approche combinant les données du séquençage de génome et l'analyse du transcriptome (RNA-Seq) sur fibroblastes, me permettant d'identifier des transcrits dérégulés qui étaient impliqués dans le développement du cerveau et de l'oeil. J'ai comparé les résultats de cette analyse avec ceux de l'analyse du génome dans le but d'identifier des variants dans ces gènes candidats. En conclusion, mon travail de thèse a permis d'améliorer la connaissance des bases moléculaires des MDC complexes et d'ouvrir des perspectives de nouveaux mécanismes tels que ceux engageant les gènes WDR81 et EPG5, et le rôle des endosomes et de l'autophagie dans les MDC, et aussi TLE1 comme nouvelle cause de microcéphalies postnatales. Mes travaux ont également permis de générer une collection de données de séquençage haut débit (WES, WGS et RNA-Seq) qui seront mises en commun dans le cadre d'un consortium international afin de développer des nouvelles stratégies d'analyse en particulier pour les séquences non codantes. Cette approche permettra également d'ouvrir la voie vers la compréhension des mécanismes cellulaires impliqués dans la formation du cerveau et de l' œilMalformations of cortical development (MCD) are a major cause of intellectual disability and drug-resistant epilepsy. Next Generation Sequencing (NGS) has considerably improved the identification of the molecular basis of non-syndromic MCD. However, certain forms, including complex MCD, remain unexplained. My PhD project aimed to improve the understanding of complex MCD using two disorders: Microlissencephaly (MLIS) and Aicardi Syndrome (AIC), the latter associating brain and eye malformations and only reported in girls. Trio Whole Exome Sequencing (WES) performed in 16 MLIS families allowed me to identify and functionally characterize a new MLIS gene, WDR81, in which mutations lead to cell cycle alteration. Moreover, using the same strategy, I was able to identify a pathogenic homozygous variant in TLE1 in a patient from consanguineous family with a postnatal microcephaly, suggestive of a FOXG1-like presentation. Interestingly, TLE1 is a major partner of FOXG1, a gene involved in maintaining the balance between progenitor proliferation and differentiation. In parallel, my work allowed me to redefine the phenotypic spectrum associated with RTTN, EPG5, COL4A1 and COL4A2, TBR1, KIF5C, KIF2A and FOXG1. The second part of my PhD program was aimed at identifying the genetic basis of AIC in an international cohort of 19 patients. After excluding a skewed X chromosome inactivation and the presence of chromosomal rearrangements, I performed WES in trios. The analysis of the data from WES did not allow me to identify any recurrent variants. I therefore tested a new approach combining Whole Genome Sequencing (WGS) and RNA-Sequencing (RNA-Seq) on fibroblast cells. I identified a number of deregulated transcripts implicated in brain and eye development. I compared the results of this analysis with the WGS analysis in order to find variants in these candidate genes. In conclusion, these studies have improved the knowledge of the molecular basis of complex MCD, such as TLE1 in postnatal microcephaly, and revealed the pathogenic mechanisms such as WDR81 in cell cycle progression and EPG5 in endosomes and autophagy. My work has also generated a collection of NGS data (WES, WGS and RNA-Seq) that will be shared in an international consortium to develop new analytical strategies, in particular for the non-coding DNA regions. This novel strategy provides opportunities to improve understanding of the cellular mechanisms involved in brain and eye development
Libri sul tema "Fetal size/growth"
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Wilton, Niall, Brian J. Anderson e Bruno Marciniak. Anatomy, physiology, and pharmacology in paediatric anaesthesia. A cura di Jonathan G. Hardman e Neil S. Morton. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199642045.003.0069.
Testo completoAbstract (sommario):
Anaesthesia for children is tempered by changes that occur during both growth and development. Drug dose is affected by size and clearance maturation processes as well as the changing body composition that occurs with age. All organ systems undergo these maturation changes and most are complete within the first few years of life. Normal physiological variables in infancy and childhood are quite different from adults. The central nervous, cardiovascular, and respiratory systems are particularly important. Cerebral immaturity and plasticity impacts sensitivity to drugs, pain responses, and behaviour and increases potential harm from apoptosis with anaesthesia. The heart undergoes a transition from fetal to adult circulation during the first few weeks of life. Undiagnosed congenital defects are not uncommon. The neonate is very susceptible to conditions that trigger an increase in pulmonary vascular resistance, with reversion to fetal circulatory patterns. Respiratory anatomy and mechanics affect the propensity to apnoea, airway maintenance, artificial ventilation modalities, uptake of inhalational agents, and tracheal tube sizes. Metabolic rate and oxygen requirements increase with decreasing age. This physiology influences diverse aspects that include the rate of desaturation during apnoea, hypoglycaemia during starvation, cardiac output, drug metabolism, fluid requirements, and heat production or loss.
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S, Zagon Ian, e Slotkin Theodore A, a cura di. Maternal substance abuse and the developing nervous system. San Diego: Academic Press, 1992.
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3
Zagon, Ian S., e Theodore A. Slotkin. Maternal Substance Abuse and the Developing Nervous System. Elsevier Science & Technology Books, 2012.
Cerca il testo completoCapitoli di libri sul tema "Fetal size/growth"
1
Snow, M. H. L. "Effect of genome on size at birth". In Fetal Growth, 3–12. London: Springer London, 1989. http://dx.doi.org/10.1007/978-1-4471-1707-0_1.
Testo completo
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Snow, Michael H. L. "Control of Embryonic Growth Rate and Fetal Size in Mammals". In Human Growth, 67–82. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2101-9_4.
Testo completo
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Hargitai, Beata. "Diagnostic Criteria of Fetal Growth Abnormalities and Interpretation of Postmortem Size and Weight Measurements". In Practical Manual of Fetal Pathology, 69–75. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-42492-3_6.
Testo completo
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Ulrich, Magda M. W. "Fetal Wound Healing". In Textbook on Scar Management, 3–9. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44766-3_1.
Testo completoAbstract (sommario):
AbstractFirst- and second-trimester fetal skin wounds are known to heal without scarring.Research has excluded factors like the sterile uterine environment as the cause of scarless repair, and it is believed that scarless healing is an intrinsic property of early fetal skin. However, increasing wound size and induction of the inflammatory reaction can evoke a scar response in the fetus.For decades, research is performed to elucidate the mechanisms responsible for scarless healing in fetuses. Much research has been performed in animal studies, and several mechanisms have been proposed to be involved such as the microenvironment and the extracellular matrix, a reduced inflammatory response, differences in growth factor profile, and differences in fibroblast phenotype.It is clear that the wound healing process leading to scarless healing cannot be attributed to just one factor or mechanism but will be the result of a complex of interconnected processes.This chapter describes some of the possible mechanisms which may play a role in scarless healing.
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Hirst, Jane E., e Aris T. Papageorghiou. "Fetal growth". In Oxford Textbook of Obstetrics and Gynaecology, a cura di Sabaratnam Arulkumaran, William Ledger, Lynette Denny e Stergios Doumouchtsis, 133–40. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198766360.003.0010.
Testo completoAbstract (sommario):
Fetal growth is a complex and highly orchestrated process. Monitoring fetal growth is one of the cornerstones of the evaluation of fetal well-being. This chapter explores the global epidemiology of poor fetal growth, the controversies around the definition of the condition, and the scientific validity of the multitude of growth charts and approaches to fetal growth currently in use around the world. In 2014, the accepted approaches to fetal growth were challenged by the findings of the international INTERGROWTH-21st Project. This major international project demonstrated that the growth of babies in utero and the size of babies around the world are remarkably similar if maternal environmental, social, and medical conditions are relatively optimal. From this study, the first standards for fetal and newborn growth have been produced. The management of babies detected to be large for gestational age (LGA) also remains controversial and a clinical challenge. With increasing rates of maternal obesity and gestational diabetes, a growing proportion of babies are born LGA or detected to be LGA in utero. Other than the treatment for gestational diabetes, the evidence for effective interventions to prevent the development of LGA during pregnancy is limited. Key issues regarding the management of LGA include the most appropriate timing and mode of delivery to prevent shoulder dystocia and birth trauma.
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Dutta, Dilip. "How to Assess Fetal Size and Growth Rate Abnormalities?" In Manual of Fetal Medicine, 33. Jaypee Brothers Medical Publishers (P) Ltd., 2009. http://dx.doi.org/10.5005/jp/books/10466_4.
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Snow, Michael H. L. "Embryonic growth and the manipulation of fetal size". In The Physiology of Human Growth, 1–10. Cambridge University Press, 1989. http://dx.doi.org/10.1017/cbo9780511896811.002.
Testo completo
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Enkin, Murray, Marc J. N. C. Keirse, James Neilson, Caroline Crowther, Lelia Duley, Ellen Hodnett e Justus Hofmeyr. "Assessment of fetal growth, size, and well-being". In Guide to Effective Care in Pregnancy and Childbirth, 79–92. Oxford University Press, 2000. http://dx.doi.org/10.1093/med/9780192631732.003.0012.
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Butler, Gary. "Child and adolescent growth". In Oxford Textbook of Endocrinology and Diabetes, 989–1006. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199235292.003.7005.
Testo completoAbstract (sommario):
The growth of a human being from a single cell to a fully mature individual is a remarkable process and something that is subject to a large number of influences across the whole growth period. Growth before birth is actually the most rapid and probably the least understood phase, but a detailed description of antenatal events is beyond this chapter. Size at birth, however, is dependent on a number of factors, primarily maternal, in particular the wellbeing of the fetoplacental unit and its level of functioning. This unit is markedly affected in maternal undernutrition, which translates into significant deleterious effects on fetal growth. Probably as important as placental function is maternal size. Small maternal size will constrain growth even when the fetus is potentially of a genetically large size. Lastly, fetal factors are important themselves. Genetic or endocrine disturbances may constrain fetal growth, but these are secondary to maternal effects. In paediatric practice we are concerned about postnatal growth. It is useful to think of growth in three separate phases: infancy, childhood, and puberty (1). The infancy phase is largely nutrition dependent and lasts for 1–2 years. After this, the childhood phase, which is predominantly growth hormone-driven takes over, and continues until the pubertal or adolescent phase. This final phase is under the influence of the sex steroids and the speed of this phase determines the timing and rate of acceleration of the pubertal growth spurt, and the cessation of growth. It is very helpful to consider the different influences on each phase when presented with the diagnostic challenge of a child with abnormal growth (2).
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Maršál, Karel, e Bertil Sundén. "The development of ultrasound in obstetrics and gynaecology in Sweden". In Ultrasound in Clinical Diagnosis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199602070.003.0011.
Testo completoAbstract (sommario):
In the field of obstetrics, the advent of diagnostic ultrasound was most welcome because of the obvious lack of a non-invasive method providing information on the fetus in utero. The subsequent very fast and widespread use of ultrasound in clinical obstetrics was vindication that the method fulfilled the expectations and that it literally ‘opened a window into the uterus’. Ultrasound enabled direct examinations of fetal anatomy, measurements of fetal size and growth, and recording of intrauterine activities. Nowadays, 97 % of all pregnant women in Sweden undergo at least one ultrasound examination during their pregnancy. The early positive results reported from the application of ultrasound in cardiology and neurosurgery at Lund University elicited interest to test the method on pregnant women at the Department of Obstetrics and Gynecology in Lund. In 1957, Alf Sjövall, then professor in obstetrics and gynaecology, discussed over a lunch-table with neurosurgeon Lars Leksell his very first experience of diagnosing subdural hematoma using ultrasound. Professor Sjövall asked then Bertil Sundén, who worked at his department, to investigate early pregnancies with the Krautkrämer echoscope belonging to Leksell. The aim was to examine whether it would be possible to detect echoes from the fetus in early pregnancies and to differentiate it from myomatous enlargements of the uterus and from ovarian tumours. The Krautkrämer echoscope offered only an A-mode display of ultrasound signals so no tangible results were obtained as the origin of the echoes could not be identified. At that time, it was unknown whether or not ultrasound might have any harmful effects on embryonic tissue and therefore these first investigations in early pregnancies were done on patients admitted for interruption of pregnancy. After that Ian Donald published the first description of an echoscope generating a two dimensional display in 1958, Bertil Sundén went on a three-week visit to Professor Donald in Glasgow. There he met electronic engineer Tom G. Brown, employed by Smiths Industrial Division in Glasgow, who had built Donald’s machine. During his stay in Glasgow Sundén performed several investigations on obstetric and gynaecological patients using Brown’s equipment that was the only one of its type.
Atti di convegni sul tema "Fetal size/growth"
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Yalcin, Huseyin C., Huseyin E. Salman e Reema Y. Kamal. "Assessment of Human Fetal Left Heart Hemodynamics during Prenatal Development". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0086.
Testo completoAbstract (sommario):
The hemodynamic forces and wall shear stresses (WSS) play an important role during the fetal heart development. Abnormal levels of flow-driven shear stress can deteriorate the proper functioning of the cells responsible for the growth and remodeling of the heart and lead to congenital heart defects (CHDs). Hypoplastic left heart syndrome (HLHS) is a critical CHD with severely underdeveloped left ventricle and responsible for 25-40% of all neonatal cardiac deaths. To characterize the main differences between the healthy and HLHS fetal hearts in terms of morphology, flow behavior, and WSS levels, will help to understand the mechanobiological development of the human fetal hearts. The comparison of healthy and HLHS fetal hearts is important to understand the embryonic development of HLHS. Computational fluid dynamics (CFD) modeling is performed to elucidate the flow behavior and WSS levels in the heart chambers. First, the model geometries are generated using the medical images. Then, the flow domain is discretized in spatial and time domains for solving the governing fluid flow equations. Inlet flow conditions are determined using the Doppler ultrasound velocity measurements. The analyses cover the range of gestational week 16 and week 34. HLHS hearts have higher peak flow rates at the valves compared to the control hearts. The turbulent activity in the left side of the heart is higher than the right side. For the control hearts, there is a balance between the left and right sides of the heart, which is preserved during the development. The ratio of the cross-sectional area between the left and right sides of the heart is about 57.5% to 42.5% for the control hearts. HLHS significantly reduces the cross-sectional area of the left side of the heart. For HLHS hearts, the ratio between the left and right sides becomes about 30% to 70%. The average WSS levels significantly increase at the left side of the HLHS hearts. This study indicates the critical importance of the altered inflow hemodynamics during the human fetal heart development. CFD analysis can be used to predict the initiation and growth of CHDs. The presence of CHDs significantly changes the biomechanical environment in the fetal hearts.
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Wang, H. T., C. J. Li, G. C. Ji e G. J. Yang. "Influence of Annealing Treatment on the Microstructure and Microhardness of Cold Sprayed Nanostructured FeAl Coating". In ITSC2011, a cura di B. R. Marple, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima e A. McDonald. DVS Media GmbH, 2011. http://dx.doi.org/10.31399/asm.cp.itsc2011p1049.
Testo completoAbstract (sommario):
Abstract In the present study, a nanostructured FeAl coating was prepared by cold spraying of ball milled powder. Annealing treatment was applied to the coating to investigate its effect on the phase structure, grain size and microhardness of the cold-sprayed nanostructured FeAl coating. The results showed that the FeAl phase was kept unchangeable when the coating annealed at the temperature above 500°C. Annealing temperature significantly influenced the microstructure and microhardness of cold-sprayed FeAl coating. With raising annealing temperature, the lamellar structure in the as-sprayed coating disappeared and a dense coating microstructure with fully bonding of deposited particles at their interfaces was achieved after annealing at 950°C. Nanograin growth of the FeAl phase occurred at an annealing temperature higher than 800°C. The microhardness of cold-sprayed FeAl coating remained about 400 Hv0.1 at the annealing temperature below 800°C and decreased to 300 Hv0.1 at 1100°C.
Rapporti di organizzazioni sul tema "Fetal size/growth"
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Spencer, Thomas E., Elisha Gootwine, Arieh Gertler e Fuller W. Bazer. Placental lactogen enhances production efficiency in sheep. United States Department of Agriculture, dicembre 2005. http://dx.doi.org/10.32747/2005.7586543.bard.
Testo completoAbstract (sommario):
The key objectives of this BARD project were to: (1) study long-term effects of immunization of prepubertal ewes against recombinant ovine placental lactogen (roPL) on subsequent birth weights of their lambs and their milk production; (2) optimize the anti-roPL immunization protocol using adjuvant preparations acceptable to producers and regulatory agencies; and (3) determine the physiological mechanism(s) whereby immunization against oPL increases fetal growth and development and mammogenesis. These objectives were based on key findings from a previous BARD project that: (a) immunization of ewes against roPL increased lamb birth weight and ewe milk production during lactation; (b) roPL and recombinant ovine growth hormone (roGH) increased the proliferation and differentiated function of endometrial glands that, in turn, would enhance uterine secretions necessary for fetal and placental growth; and (c) exogenous roPL and roGH stimulated mammogenesis and milk production during lactation. The BARD projects address central problems in sheep production, including reproductive failure due to embryonic/fetal mortality, low birth weight of lambs especially in prolific breeds, and reduced milk yields which affect neonatal survival. The sheep placenta secretes both lactogenic (oPL) and somatogenic (oGH) hormones. The receptors for those hormones are present in the fetus and placenta as well as maternal uterus, and mammary gland. Our research has focused on determining the biological role of these placental hormones in development and differentiation of the uterus during gestation and the mammary gland during pregnancy and lactation. Studies conducted in the current BARD project indicated that the effects of anti-roPL immunization were variable in ewes and that commercially available and widely acceptable adjuvant preparations were not effective to produce high anti-roPL titers in pre-pubertal ewes. In the non-prolific Rambouillet ewe in Texas and in the Awassi and the Assaf in Israel, anti-roPL immunization increased lamb birth weight; however, the magnitude of this effect and the inherent variability precluded our ability to determine the physiological mechanism of how the immunization increases fetal growth. Collectively, our findings suggest that anti-roPL immunization is not currently feasible as an easy and efficacious tool for the producer to increase flock reproductive and production efficiency. The variability in response of individual ewes to anti-roPL immunization likely includes modifying the recombinant hormone and the type of adjuvant used for the immunization. In particular, the oPL may need to be modified to ensure maximum antigenicity in a broad range of breed types. Nonetheless, the investigators continue to collaborate on identifying fundamental mechanisms that can be improved by genetics or management to enhance the efficiency of uteroplacental function and, in turn, fetal growth and development. High prolificacy is a desirable trait in intensive sheep production systems. One of the main limitations of using prolific breeds of sheep is that increased litter size is associated with low birth weights and increased mortality of lambs. Further, low birth weight is associated with an increased propensity for adult diseases and decreased production efficiency. Indeed, our recent studies find that the birth weights of lambs born in large litters can be improved by both genetics and management. Future cooperative research will continue to focus on reproductive efficiency of sheep that have broader implications for improving production efficiency in all types of ruminant livestock.