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2.
Clin Obstet Gynecol ; 67(2): 381-398, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38450526

RESUMO

Over the last 4 decades, significant advances in the care of HIV during pregnancy have successfully reduced, and nearly eliminated, the risk of perinatal HIV transmission. The baseline risk of transmission without intervention (25% to 30%) is now <1% to 2% in the United States with contemporary antepartum, intrapartum, and postnatal interventions. In this review, we discuss 3 landmark clinical trials that substantially altered obstetric practice for pregnant individuals with HIV and contributed to this extraordinary achievement: 1) the Pediatric AIDS Clinical Trials Group 076 Trial determined that antepartum and intrapartum administration of antiretroviral drug zidovudine to the pregnant individual, and postnatally to the newborn, could reduce the risk of perinatal transmission by approximately two-thirds; 2) the European Mode of Delivery Collaboration Trial demonstrated performance of a prelabor cesarean birth before rupture of membranes among pregnant people with viremia reduced the risk of perinatal transmission compared with vaginal birth; and 3) the International Maternal Pediatric Adolescent AIDS Clinical Trials Network 2010 Trial identified that dolutegravir-containing, compared with efavirenz-containing, antiretroviral regimens during pregnancy achieved a significantly higher rate of viral suppression at delivery with shorter time to viral suppression, with fewer adverse pregnancy outcomes. Collectively, these trials not only advanced obstetric practice but also advanced scientific understanding of the timing, mechanisms, and determinants of perinatal HIV transmission. For each trial, we will describe key aspects of the study protocol and outcomes, insights gleaned about the dynamics of perinatal transmission, how each study changed clinical practice, and relevant updates to current practice since the trial's publication.


Assuntos
Alcinos , Fármacos Anti-HIV , Infecções por HIV , Transmissão Vertical de Doenças Infecciosas , Complicações Infecciosas na Gravidez , Piridonas , Zidovudina , Humanos , Gravidez , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/transmissão , Infecções por HIV/prevenção & controle , Complicações Infecciosas na Gravidez/tratamento farmacológico , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Piridonas/uso terapêutico , Zidovudina/uso terapêutico , Fármacos Anti-HIV/uso terapêutico , Oxazinas/uso terapêutico , Piperazinas/uso terapêutico , Ciclopropanos/uso terapêutico , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Ensaios Clínicos como Assunto , Benzoxazinas/uso terapêutico , Benzoxazinas/administração & dosagem , Recém-Nascido , Cesárea
3.
AIDS Res Hum Retroviruses ; 40(4): 257-267, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37772708

RESUMO

Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) are vital for fetal metabolic programming and immunomodulation. Higher n-6:n-3 ratios, reflecting a proinflammatory eicosanoid profile, are associated with adverse perinatal outcomes. Limited data exist, however, on n-6 and n-3 PUFAs specifically in the context of HIV and pregnancy. Our objective was to assess HIV clinical factors associated with PUFA signatures in pregnant persons with HIV (PWH). In this observational cohort, third trimester plasma PUFA concentrations (six n-6 PUFAs, four n-3 PUFAs) were measured, each as a percent of total fatty acid content, via esterification and gas chromatography in pregnant PWH enrolled from 2009 to 2011 in the Nutrition substudy of the Pediatric HIV/AIDS Cohort Study. PUFA ratios (n-6:n-3) were calculated. Exposures assessed were first/second trimester CD4 count (<200 vs. >200 cells/mm3), HIV RNA viral load (VL) (VL >400 vs. <400 copies/mL), and protease inhibitor (PI) versus non-PI antiretroviral therapy (ART). Linear regression models using generalized estimating equations were fit to assess mean differences and their 95% confidence intervals (CIs) in n-6:n-3 by each exposure, adjusted for potential confounders. Of 264 eligible pregnant PWH, the median age was 27 years, 12% had CD4 counts <200 cells/mm3, and 56% had VL ≥400 copies/mL in the first/second trimesters. PUFA concentrations and ratios were similar by CD4 count and PI exposure. n-3 concentrations were lower in PWH with VL ≥400 versus <400 copies/mL (median 2.8% vs. 3.0%, p < .01, respectively); no differences were observed for n-6 concentrations by VL. In models adjusted for age, education, tobacco use, body mass index, and PI-based ART, n-6:n-3 was higher in those with VL ≥400 copies/mL (mean difference: 1.6; 95% CI: 0.79-2.48, p = .0001). Therefore, PUFA signatures in viremic pregnant PWH reflect a proinflammatory eicosanoid milieu. Future studies should evaluate associations of proinflammatory PUFA signatures with adverse perinatal outcomes in PWH.


Assuntos
Síndrome da Imunodeficiência Adquirida , Ácidos Graxos Ômega-3 , Infecções por HIV , Gravidez , Feminino , Humanos , Criança , Adulto , Estudos de Coortes , Ácidos Graxos/uso terapêutico , Infecções por HIV/tratamento farmacológico , Viremia/tratamento farmacológico , Ácidos Graxos Ômega-3/uso terapêutico , Antirretrovirais/uso terapêutico , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Eicosanoides/uso terapêutico , Carga Viral
5.
J Diabetes Sci Technol ; 17(5): 1337-1363, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37542367

RESUMO

BACKGROUND: The use of continuous subcutaneous insulin infusion (CSII) therapy in pregnancies affected by pregestational diabetes mellitus (DM) has generated mixed outcome data worthy of further investigation. This systematic review and meta-analysis aims to evaluate clinical outcomes associated with CSII versus multiple daily injections (MDIs) in pregnant persons with pregestational DM. METHODS: A predefined, systematic, librarian-assisted search of MEDLINE (PubMed), Embase, Cochrane Library, Scopus, ClinicalTrials.gov, and World Health Organization International Clinical Trial Registry Platform (published from 2010 to 2022) yielded 3003 studies describing pregnancy outcomes associated with CSII and/or MDI for pregestational DM. The primary exposure was mode of insulin administration, with cesarean delivery and neonatal hypoglycemia as the primary maternal and neonatal outcomes, respectively. Secondary outcomes included hypertensive disorders of pregnancy, first and third-trimester glycemic control, large-for-gestational age (LGA) neonate, preterm birth, neonatal intensive care unit admission, need for respiratory support, hyperbilirubinemia, 5-minute Apgar <7, shoulder dystocia, and perinatal mortality. We calculated pooled odds ratios (OR) with 95% confidence intervals (CI) using random-effects models. RESULTS: Among 39 eligible studies, 39% of the 5518 pregnancies included were exposed to CSII. Odds of cesarean delivery were higher with CSII (20 studies: 63% vs 56%, odds ratio [OR] 1.3 [95% confidence interval (CI) 1.2-1.5]), but we did not identify a difference in the odds of neonatal hypoglycemia (23 studies: 31% vs 34%, OR 1.1 [95% CI 0.9-1.5]). Among secondary outcomes, only the odds of LGA (20 studies: 47% vs 38%, OR 1.4 [95% CI 1.2-1.6]) were higher in individuals using CSII versus MDI. CONCLUSIONS: Use of CSII (vs MDI) for pregestational DM in pregnancy is associated with higher odds of cesarean delivery and delivery of an LGA neonate. Further evaluation of how CSII use may influence neonatal size and delivery route is warranted.


Assuntos
Diabetes Mellitus Tipo 1 , Hipoglicemia , Gravidez em Diabéticas , Nascimento Prematuro , Gravidez , Feminino , Recém-Nascido , Humanos , Insulina/uso terapêutico , Hipoglicemiantes/uso terapêutico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Gravidez em Diabéticas/tratamento farmacológico , Hemoglobinas Glicadas , Nascimento Prematuro/tratamento farmacológico , Insulina Regular Humana/uso terapêutico , Hipoglicemia/induzido quimicamente , Hipoglicemia/epidemiologia , Hipoglicemia/tratamento farmacológico , Infusões Subcutâneas , Injeções Subcutâneas , Sistemas de Infusão de Insulina
6.
JAMA ; 329(9): 758-759, 2023 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-36763352

RESUMO

This JAMA Insights Clinical Update discusses general adaptations for pregnancy after bariatric surgery, including recommendations regarding nutrition, maternal health, and fetal and neonatal risks.


Assuntos
Cirurgia Bariátrica , Complicações na Gravidez , Feminino , Humanos , Gravidez , Cirurgia Bariátrica/efeitos adversos , Complicações na Gravidez/etiologia , Resultado da Gravidez
7.
Am J Obstet Gynecol MFM ; 4(5): 100676, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35714861

RESUMO

BACKGROUND: Recent studies have suggested a possible benefit of valaciclovir prophylaxis to prevent vertical transmission after a positive serologic screen for primary maternal cytomegalovirus infection during pregnancy, although its cost-effectiveness remains uncertain. OBJECTIVE: This study aimed to determine the circumstances under which universal first-trimester maternal serologic screening for maternal cytomegalovirus infection, with valaciclovir prophylaxis to prevent congenital cytomegalovirus, is cost-effective. STUDY DESIGN: This study was a decision analysis from the perspective of the pregnant person to assess whether universal maternal screening in the first trimester of pregnancy, with subsequent valaciclovir prophylaxis (8 g/day from the time of positive serologic screen for primary maternal cytomegalovirus infection to 21 weeks of gestation) for those who are acutely infected, is cost-effective compared with usual care (ie, no routine serologic screening but with amniocentesis if midtrimester sonographic findings suggest cytomegalovirus). For baseline estimates, this study assumed a 35% risk of congenital cytomegalovirus after primary maternal infection and a 71% risk reduction with valaciclovir. This study varied valaciclovir's efficacy to identify whether and at what threshold universal screening would be estimated to be cost-effective, compared with usual care. Monte Carlo analyses were performed. A willingness-to-pay threshold of $100,000/quality-adjusted life year was used to define cost-effectiveness. RESULTS: Under base case estimates, first-trimester universal screening and valaciclovir prophylaxis for seropositive pregnant persons with acute cytomegalovirus infection were not cost-effective, with a cost of $137,854 per maternal quality-adjusted life year but resulted in 14 fewer children affected with cytomegalovirus per 100,000 pregnancies compared with usual care. In 1-way sensitivity analysis, universal screening and treatment were estimated to be the cost-effective strategy if the incidence of primary maternal cytomegalovirus infection exceeds 2.6%, the baseline risk of vertical transmission of cytomegalovirus without prophylaxis is greater than 36.8%, and the risk reduction of vertical transmission of cytomegalovirus with valaciclovir prophylaxis exceeds 75.9%. In Monte Carlo analyses, first-trimester universal serologic screening with valaciclovir prophylaxis was estimated to be the cost-effective strategy in 46.8% of runs. CONCLUSION: Universal first-trimester serologic screening with valaciclovir prophylaxis is not the cost-effective strategy for antenatal management of cytomegalovirus under the base case estimates. Although universal screening is cost-effective in certain circumstances when the efficacy of valaciclovir exceeds the base case, that result was not robust to variation of estimates across their reasonable ranges. These data can inform future studies to evaluate screening and treatment to prevent congenital cytomegalovirus.


Assuntos
Infecções por Citomegalovirus , Complicações Infecciosas na Gravidez , Criança , Análise Custo-Benefício , Citomegalovirus , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/epidemiologia , Infecções por Citomegalovirus/prevenção & controle , Feminino , Humanos , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/tratamento farmacológico , Complicações Infecciosas na Gravidez/epidemiologia , Primeiro Trimestre da Gravidez , Valaciclovir/uso terapêutico
8.
Clin Obstet Gynecol ; 65(2): 290-301, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35467576

RESUMO

Within the evolving field of obstetrics and gynecology, providers should possess the ability to effectively and critically evaluate medical literature in order to best adapt and incorporate evidence-based practice. For both clinicians and researchers alike, we provide a systematic approach for reviewing a journal article published in the medical literature. We summarize the various types of study designs, with dedicated attention to observational and experimental studies, and examine sources of bias inherent to these study designs. Finally, we review important considerations when interpreting the validity and significance of the results and conclusions of a research study.


Assuntos
Ginecologia , Obstetrícia , Viés , Feminino , Humanos , Gravidez , Projetos de Pesquisa
9.
Am J Obstet Gynecol MFM ; 4(1): 100493, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34562637

RESUMO

BACKGROUND: Prior studies have reported decreases in the preterm delivery incidence during the COVID-19 pandemic. However, the findings are inconsistent. Given the wide disparities in the pandemic's impact across communities, neighborhood deprivation may explain the observed variation in the relationship between the COVID-19 pandemic and preterm delivery. OBJECTIVE: To characterize the changes in the incidence of preterm delivery during the COVID-19 pandemic with attention to the effect modification introduced by neighborhood hardship. STUDY DESIGN: This retrospective cohort study included all the pregnant patients who delivered at an urban tertiary care hospital during the pandemic (April-November 2020) or before the pandemic (April-November 2019). We compared the incidence of preterm delivery, spontaneous preterm delivery, and medically indicated preterm delivery before 37 weeks' gestation across epochs. Planned analyses stratified the cohorts by neighborhood deprivation metrics defined by the residential zip code; the metrics included the median neighborhood household income and the hardship index (a composite index including dependency, educational attainment, unemployment, poverty, per capita income, and crowded housing). The Breslow-Day test for homogeneity assessed the association of the delivery epoch and neighborhood deprivation with the preterm delivery outcomes. RESULTS: Of 16,544 eligible deliveries, 8.7% occurred preterm. The incidences of preterm delivery (8.4% vs 9.0%; P=.17), spontaneous preterm delivery (5.0 vs 5.4%; P=.27), and medically indicated preterm delivery (3.2% vs 3.5%; P=.47) were similar in the pandemic and prepandemic epochs. However, the preterm delivery (odds ratio, 0.78; 95% confidence interval, 0.64-0.96) and spontaneous preterm delivery (odds ratio, 0.76; 95% confidence interval, 0.59-0.99) decreased from the prepandemic to the pandemic epoch in those living in neighborhoods <50th percentile for median income (Breslow-Day P values.047 and.036, respectively). Similarly, the preterm delivery (odds ratio, 0.78; 95% confidence interval, 0.64-0.97) and spontaneous preterm delivery (odds ratio, 0.74; 95% confidence interval, 0.57-0.98) decreased for those inhabiting the neighborhoods in the highest-hardship quartile (Breslow-Day P values.045 and.029, respectively). CONCLUSION: The populations residing in socioeconomically disadvantaged neighborhoods experienced reductions in preterm delivery during the COVID-19 pandemic. Neighborhood-level social determinants of health offer insight into the complex etiologies that contribute to preterm delivery and provide opportunities for public health and equity-focused prevention strategies.


Assuntos
COVID-19 , Nascimento Prematuro , Feminino , Humanos , Recém-Nascido , Pandemias , Gravidez , Nascimento Prematuro/epidemiologia , Estudos Retrospectivos , SARS-CoV-2
10.
Am J Obstet Gynecol MFM ; 3(6): 100458, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34403821

RESUMO

BACKGROUND: Inflammatory biomarkers have been used to portend disease severity in nonpregnant individuals with SARS-CoV-2 infection. However, currently, limited data are available, and with mixed results, to elucidate which inflammatory biomarkers may be most associated with clinical phenotype in pregnant patients. OBJECTIVE: We aimed to compare laboratory findings among pregnant patients with SARS-CoV-2 infection by symptom status and disease severity. STUDY DESIGN: We retrospectively evaluated pregnant patients with positive SARS-CoV-2 infection, confirmed through polymerase chain reaction testing, at an urban academic US hospital between March 2020 and October 2020, performed for reported symptoms or universal screening on admission. In our hospital, all patients with SARS-CoV-2 infection were recommended to have baseline laboratory testing, including leukocyte, neutrophil, and lymphocyte counts; aspartate aminotransferase and alanine aminotransferase; high-sensitivity C-reactive protein; procalcitonin; lactate dehydrogenase; D-dimer; and ferritin. We performed multivariable logistic regression to evaluate peak laboratory abnormalities significantly associated with symptomatic SARS-CoV-2 infection and disease severity with gestational age at diagnosis, maternal age, and obesity as covariates. The sensitivity and specificity of laboratory abnormalities were calculated to identify symptomatic vs asymptomatic infection and severe to critical disease vs mild to moderate disease. RESULTS: We identified 175 pregnant patients with SARS-CoV-2 infection, of whom 100 (57%) were symptomatic; 17 (17%) of those who were symptomatic had a severe to critical disease. Laboratory data were available for 128 patients, of whom 67 (52%) were symptomatic. Compared with asymptomatic individuals, symptomatic individuals were more likely to exhibit elevated high-sensitivity C-reactive protein levels after adjusting for gestational age (adjusted odds ratio, 5.67; 95% confidence interval, 1.42-22.52; sensitivity, 81%; specificity, 43%). In symptomatic individuals, transaminitis (adjusted odds ratio, 5.67; 95% confidence interval, 1.27-25.43), elevated procalcitonin levels (adjusted odds ratio, 16.60; 95% confidence interval, 2.61-105.46), and elevated lactate dehydrogenase levels (adjusted odds ratio, 17.55; 95% confidence interval, 2.51-122.78) were independently associated with severe to critical disease rather than mild to moderate disease after adjusting for maternal age and obesity. For differentiating disease severity, sensitivity rates for transaminitis, procalcitonin elevation, and lactate dehydrogenase elevation were 47%, 87%, and 53%, respectively, whereas the specificity rates were 89%, 63%, and 90%, respectively. CONCLUSION: Inflammatory biomarkers in pregnant patients with SARS-CoV-2 infection exhibited vast heterogeneity, poor discriminative ability, and thereby limited clinical utility. Larger registry studies should evaluate which inflammatory biomarkers may be most useful for risk stratification and prognostication of pregnant patients with SARS-CoV-2 infection, taking into account the physiology of pregnancy.


Assuntos
COVID-19 , SARS-CoV-2 , Infecções Assintomáticas/epidemiologia , Feminino , Humanos , Laboratórios , Gravidez , Estudos Retrospectivos
11.
Biomaterials ; 178: 751-766, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29452913

RESUMO

Breast cancer cell invasion is influenced by growth factor concentration gradients in the tumor microenvironment. However, studying the influence of growth factor gradients on breast cancer cell invasion is challenging due to both the complexities of in vivo models and the difficulties in recapitulating the tumor microenvironment with defined gradients using in vitro models. A defined hyaluronic acid (HA)-based hydrogel crosslinked with matrix metalloproteinase (MMP) cleavable peptides and modified with multiphoton labile nitrodibenzofuran (NDBF) was synthesized to photochemically immobilize epidermal growth factor (EGF) gradients. We demonstrate that EGF gradients can differentially influence breast cancer cell invasion and drug response in cell lines with different EGF receptor (EGFR) expression levels. Photopatterned EGF gradients increase the invasion of moderate EGFR expressing MDA-MB-231 cells, reduce invasion of high EGFR expressing MDA-MB-468 cells, and have no effect on invasion of low EGFR-expressing MCF-7 cells. We evaluate MDA-MB-231 and MDA-MB-468 cell response to the clinically tested EGFR inhibitor, cetuximab. Interestingly, the cellular response to cetuximab is completely different on the EGF gradient hydrogels: cetuximab decreases MDA-MB-231 cell invasion but increases MDA-MB-468 cell invasion and cell number, thus demonstrating the importance of including cell-microenvironment interactions when evaluating drug targets.


Assuntos
Neoplasias da Mama/patologia , Fator de Crescimento Epidérmico/farmacologia , Hidrogéis/química , Proteínas Imobilizadas/farmacologia , Luz , Feminino , Furanos/química , Humanos , Ácido Hialurônico/química , Células MCF-7 , Invasividade Neoplásica
12.
J Am Chem Soc ; 139(22): 7416-7427, 2017 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-28481537

RESUMO

Hydrogels are used in a wide variety of biomedical applications including tissue engineering, biomolecule delivery, cell delivery, and cell culture. These hydrogels are often designed with a specific biological function in mind, requiring the chemical incorporation of bioactive factors to either mimic extracellular matrix or to deliver a payload to diseased tissue. Appropriate synthetic techniques to ligate bioactive factors, such as peptides and proteins, onto hydrogels are critical in designing materials with biological function. Here, we outline strategies for peptide and protein immobilization. We specifically focus on click chemistry, enzymatic ligation, and affinity binding for transient immobilization. Protein modification strategies have shifted toward site-specific modification using unnatural amino acids and engineered site-selective amino acid sequences to preserve both activity and structure. The selection of appropriate protein immobilization strategies is vital to engineering functional hydrogels. We provide insight into chemistry that balances the need for facile reactions while maintaining protein bioactivity or desired release.


Assuntos
Química Click/métodos , Hidrogéis/química , Peptídeos/química , Biomimética , Reação de Cicloadição , Engenharia Tecidual/métodos
13.
Org Biomol Chem ; 14(35): 8289-300, 2016 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-27529405

RESUMO

The photochemical release of chemical reagents and bioactive molecules provides a useful tool for spatio-temporal control of biological processes. However, achieving this goal requires the development of highly efficient one- and two-photon sensitive photo-cleavable protecting groups. Thiol-containing compounds play critical roles in biological systems and bioengineering applications. While potentially useful for sulfhydryl protection, the 6-bromo-7-hydroxy coumarin-4-ylmethyl (Bhc) group can undergo an undesired photoisomerization reaction upon irradiation that limits its uncaging efficiency. To address this issue, here we describe the development of 6-bromo-7-hydroxy-3-methylcoumarin-4-ylmethyl (mBhc) as an improved group for thiol-protection. One- and two-photon photolysis reactions demonstrate that a peptide containing a mBhc-caged thiol undergoes clean and efficient photo-cleavage upon irradiation without detectable photoisomer production. To test its utility for biological studies, a K-Ras-derived peptide containing an mBhc-protected thiol was prepared by solid phase peptide synthesis using Fmoc-Cys(mBhc)-OH for the introduction of the caged thiol. Irradiation of that peptide using either UV or near IR light in presence of protein farnesyltransferase (PFTase), resulted in generation of the free peptide which was then recognized by the enzyme and became farnesylated. To show the utility of this caging group in biomaterial applications, we covalently modified hydrogels with mBhc-protected cysteamine. Using multi-photon confocal microscopy, highly defined volumes of free thiols were generated inside the hydrogels and visualized via reaction with a sulfhydryl-reactive fluorophore. The simple synthesis of mBhc and its efficient removal by one- and two-photon processes make it an attractive protecting group for thiol caging in a variety of applications.

14.
Nat Biotechnol ; 32(10): 1026-35, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25240927

RESUMO

The epicardium supports cardiomyocyte proliferation early in development and provides fibroblasts and vascular smooth muscle cells to the developing heart. The epicardium has been shown to play an important role during tissue remodeling after cardiac injury, making access to this cell lineage necessary for the study of regenerative medicine. Here we describe the generation of epicardial lineage cells from human pluripotent stem cells by stage-specific activation of the BMP and WNT signaling pathways. These cells display morphological characteristics and express markers of the epicardial lineage, including the transcription factors WT1 and TBX18 and the retinoic acid-producing enzyme ALDH1A2. When induced to undergo epithelial-to-mesenchymal transition, the cells give rise to populations that display characteristics of the fibroblast and vascular smooth muscle lineages. These findings identify BMP and WNT as key regulators of the epicardial lineage in vitro and provide a model for investigating epicardial function in human development and disease.


Assuntos
Linhagem da Célula/fisiologia , Pericárdio/citologia , Células-Tronco Pluripotentes/citologia , Aldeído Desidrogenase/metabolismo , Animais , Proteína Morfogenética Óssea 4/metabolismo , Transição Epitelial-Mesenquimal/fisiologia , Humanos , Camundongos , Miócitos Cardíacos/citologia , Via de Sinalização Wnt/fisiologia
16.
Langmuir ; 29(24): 7393-400, 2013 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-23343008

RESUMO

Hydrogels are used to create 3D microenvironments with properties that direct cell function. The current study demonstrates the versatility of hyaluronic acid (HA)-based hydrogels with independent control over hydrogel properties such as mechanics, architecture, and the spatial distribution of biological factors. Hydrogels were prepared by reacting furan-modified HA with bis-maleimide-poly(ethylene glycol) in a Diels-Alder click reaction. Biomolecules were photopatterned into the hydrogel by two-photon laser processing, resulting in spatially defined growth factor gradients. The Young's modulus was controlled by either changing the hydrogel concentration or the furan substitution on the HA backbone, thereby decoupling the hydrogel concentration from mechanical properties. Porosity was controlled by cryogelation, and the pore size distribution, by the thaw temperature. The addition of galactose further influenced the porosity, pore size, and Young's modulus of the cryogels. These HA-based hydrogels offer a tunable platform with a diversity of properties for directing cell function, with applications in tissue engineering and regenerative medicine.


Assuntos
Matriz Extracelular/química , Ácido Hialurônico/química , Hidrogéis/química , Engenharia Tecidual
17.
Fertil Steril ; 78(2): 280-5, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12137863

RESUMO

OBJECTIVE: To evaluate the ovarian follicular dynamics of cycle modification with the aromatase inhibitor letrozole compared with clomiphene citrate in normal ovulatory women. DESIGN: Randomized double-blind controlled trial. SETTING: Tertiary care hospital. PATIENT(S): Nineteen ovulatory female volunteers, ages 18-35 years. INTERVENTION(S): Subjects were monitored in one control cycle. Subjects then received either letrozole 2.5 mg daily or clomiphene citrate 50 mg daily on days 5-9 after menses. MAIN OUTCOME MEASURE(S): Number of mature follicles, endometrial thickness and endometrial pattern at ovulation, and follicular profiles of LH, FSH, and E(2). RESULT(S): The number of mature follicles at the LH surge in natural cycles was 1.0 with an exaggerated response seen for treatment both with clomiphene and letrozole. There was no difference in the endometrial thickness at midcycle during either the natural cycles or the medicated cycles. LH surges and spontaneous ovulation were documented in all natural and medicated cycles. When measured daily, follicular profiles of LH and FSH are similar between the groups in both the natural and medicated cycles. In the medicated cycles, clomiphene results in a significant increase in E(2) levels, while E(2) levels in letrozole-stimulated cycles appeared lower than in natural cycles. CONCLUSION(S): Transient inhibition of aromatase activity in the early follicular phase with the aromatase inhibitor letrozole results in stimulation of ovarian folliculogenesis similar to that seen with clomiphene citrate with no apparent adverse effect on endometrial thickness or pattern at midcycle.


Assuntos
Inibidores da Aromatase , Clomifeno/farmacologia , Antagonistas de Estrogênios/farmacologia , Fármacos para a Fertilidade Feminina/farmacologia , Nitrilas/farmacologia , Ovulação/efeitos dos fármacos , Triazóis/farmacologia , Adolescente , Adulto , Método Duplo-Cego , Hormônio Foliculoestimulante/sangue , Humanos , Letrozol , Pessoa de Meia-Idade , Projetos Piloto
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