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Building Word Knowledge, Learning Strategies, and Metacognition with the Word-Knowledge E-Book. COMPUTERS & EDUCATION 2019; 128:284-311. [PMID: 30923418 PMCID: PMC6433172 DOI: 10.1016/j.compedu.2018.09.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Many children fail to comprehend what they read because they do not monitor their understanding, which requires making accurate judgements of what they know and then employing repair strategies when comprehension fails. Relying on research from learning science and cognitive and developmental psychology, we developed the Word Knowledge e-Book (WKe-Book) to improve children's calibration of their word knowledge, strategy use, and word knowledge overall; skills which are associated with reading comprehension. The WKe-Book, which is read on a tablet computer, is a choose-your-own adventure book where choices require choosing between two rare words (e.g., cogitate vs. procrastinate). Depending on the word chosen, the story follows a different plot. There are also embedded comprehension questions where students receive immediate feedback with consequences for incorrect answers, such as being sent back to reread a few pages. In a randomized controlled trial, we tested whether students (N = 603 in 25 third through fifth grade classrooms in Arizona in the US) reading the WKe-Book would demonstrate improved word knowledge, strategy use, and word knowledge calibration. Classrooms were randomly assigned to read the WKe-Book immediately (treatment) or later (delayed-treatment control), and within classrooms, students were randomly assigned to either participate in a 15-minute weekly book club (book club treatment) or to read the WKe-Book independently with no book club (no book club control). Results revealed a significant treatment effect of the WKe-Book on students' word knowledge, word knowledge calibration, and strategy use, which predicted student performance on standardized reading comprehension and vocabulary measures. The effects were greater for students who participated in weekly book clubs compared to students in the no book club control. These findings suggest that the affordances offered by technology, which are unavailable in paper-based books, can support students' development of metacognition, including word knowledge calibration, strategy use, and word learning skills.
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Examining the relations between self-regulation and achievement in third grade students. ASSESSMENT FOR EFFECTIVE INTERVENTION : OFFICIAL JOURNAL OF THE COUNCIL FOR EDUCATIONAL DIAGNOSTIC SERVICES 2017; 42:97-109. [PMID: 28439211 PMCID: PMC5400292 DOI: 10.1177/1534508416670367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Children with stronger self-regulation skills generally demonstrate greater overall success in school both academically and socially. However, there are few valid and reliable measures of self-regulation in middle elementary school. Such a measure could help identify whether a child is truly having difficulties. Thus, the Remembering Rules and Regulation Picture Task (RRRP) was developed. The aim of this study was to develop scoring systems for the RRRP and then to examine the associations between RRRP and independent measures of self-regulation and academic achievement in mathematics and reading. Children (n = 282) from 34 third grade classrooms in Florida participated in this study. Results revealed that the RRRP captured three constructs: working memory, attentional flexibility, and inhibitory control. Hierarchical linear modeling (HLM) demonstrated that the RRRP was significantly and positively associated with other measures of self-regulation. The RRRP was significantly and positively associated with mathematics and reading as well. The RRRP appears to be a promising measure of children's self-regulation skills.
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Reciprocal Effects of Self-Regulation, Semantic Knowledge, and Reading Comprehension in Early Elementary School. Child Dev 2016; 87:1813-1824. [PMID: 27264645 PMCID: PMC5138137 DOI: 10.1111/cdev.12570] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Many assume that cognitive and linguistic processes, such as semantic knowledge (SK) and self-regulation (SR), subserve learned skills like reading. However, complex models of interacting and bootstrapping effects of SK, SR, instruction, and reading hypothesize reciprocal effects. Testing this "lattice" model with children (n = 852) followed from first to second grade (5.9-10.4 years of age) revealed reciprocal effects for reading and SR, and reading and SK, but not SR and SK. More effective literacy instruction reduced reading stability over time. Findings elucidate the synergistic and reciprocal effects of learning to read on other important linguistic, self-regulatory, and cognitive processes; the value of using complex models of development to inform intervention design; and how learned skills may influence development during middle childhood.
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Children's behavioral regulation and literacy: The impact of the first grade classroom environment. J Sch Psychol 2015; 53:409-28. [PMID: 26407837 DOI: 10.1016/j.jsp.2015.07.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 07/14/2015] [Accepted: 07/21/2015] [Indexed: 11/18/2022]
Abstract
Classroom learning environments are an important source of influence on children's development, particularly with regard to literacy achievement and behavioral regulation, both of which require the coordination of task inhibition, attention, and working memory. Classroom observations were conducted in 18 schools and 51 first grade classrooms for 500 children. The non-instructional activities were recorded for each student in the classroom. Hierarchical linear modeling revealed that children with weaker fall behavioral regulation were more likely to attend classrooms where more time was spent in disruptions and wasted instructional time over the course of the school year, such as waiting for the teacher to gather materials before beginning instruction. For literacy outcomes, children who were in classrooms where more time in disruptions, transitions, and waiting was observed showed weaker literacy skill gains in the spring compared to children in classrooms with lesser amounts of such unproductive non-instructional time and this effect was generally greater for students with initial weaker skills. These results also reveal that the classroom environment and the incoming characteristics of the students themselves influence students' development of behavioral regulation and literacy.
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Individual differences in fifth graders' reading and language predict their comprehension monitoring development: An eye-movement study. SCIENTIFIC STUDIES OF READING : THE OFFICIAL JOURNAL OF THE SOCIETY FOR THE SCIENTIFIC STUDY OF READING 2015; 19:114-134. [PMID: 27065721 PMCID: PMC4824948 DOI: 10.1080/10888438.2014.943905] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this study, we investigated fifth-graders' (n=52) fall literacy, academic language, and motivation, and how these skills predicted fall and spring comprehension monitoring on an eye movement task. Comprehension monitoring was defined as the identification and repair of misunderstandings when reading text. In the eye movement task, children read two sentences; the second included either a plausible or implausible word in the context of the first sentence. Stronger readers had shorter reading times overall suggesting faster processing of text. Generally fifth-graders reacted to the implausible word (i.e., longer gaze duration on the implausible v. the plausible word, which reflects lexical access). Students with stronger academic language, compared to those with weaker academic language, generally spent more time re-reading the implausible target compared to the plausible target. This difference increased from fall to spring. Results support the centrality of academic language for meaning integration, setting standards of coherence, and utilizing comprehension repair strategies.
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Capturing the complexity: Content, type, and amount of instruction and quality of the classroom learning environment synergistically predict third graders' vocabulary and reading comprehension outcomes. JOURNAL OF EDUCATIONAL PSYCHOLOGY 2014; 106:762-778. [PMID: 25400293 DOI: 10.1037/a0035921] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We examined classrooms as complex systems that affect students' literacy learning through interacting effects of content and amount of time individual students spent in literacy instruction along with the global quality of the classroom-learning environment. We observed 27 third grade classrooms serving 315 target students using two different observation systems. The first assessed instruction at a more micro-level; specifically, the amount of time individual students spent in literacy instruction defined by the type of instruction, role of the teacher, and content. The second assessed the quality of the classroom-learning environment at a more macro level focusing on classroom organization, teacher responsiveness, and support for vocabulary and language. Results revealed that both global quality of the classroom learning environment and time individual students spent in specific types of literacy instruction covering specific content interacted to predict students' comprehension and vocabulary gains whereas neither system alone did. These findings support a dynamic systems model of how individual children learn in the context of classroom literacy instruction and the classroom-learning environment, which can help to improve observations systems, advance research, elevate teacher evaluation and professional development, and enhance student achievement.
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Role of novel type I interferon epsilon in viral infection and mucosal immunity. Mucosal Immunol 2012; 5:610-22. [PMID: 22617838 PMCID: PMC3481022 DOI: 10.1038/mi.2012.35] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 04/03/2012] [Indexed: 02/04/2023]
Abstract
Intranasal infection with vaccinia virus co-expressing interferon epsilon (VV-HIV-IFN-ε) was used to evaluate the role of IFN-ε in mucosal immunity. VV-HIV- IFN-ε infection induced a rapid VV clearance in lung that correlated with (i) an elevated lung VV-specific CD8(+)CD107a(+)IFN-γ(+) population expressing activation markers CD69/CD103, (ii) enhanced lymphocyte recruitment to lung alveoli with reduced inflammation, and (iii) an heightened functional/cytotoxic CD8(+)CD4(+) T-cell subset (CD3(hi)CCR7(hi)CD62L(lo)) in lung lymph nodes. These responses were different to that observed with intranasal VV-HA-IFN-α(4) or VV-HA-IFN-β infections. When IFN-ε was used in an intranasal/intramuscular heterologous HIV prime-boost immunization, elevated HIV-specific effector, but not memory CD8(+)T cells responses, were observed in spleen, genito-rectal nodes, and Peyer's patch. Homing marker α4β7 and CCR9 analysis indicated that unlike other type I IFNs, IFN-ε could promote migration of antigen-specific CD8(+)T cells to the gut. Our results indicate that IFN-ε has a unique role in the mucosae and most likely can be used to control local lung and/or gut infections (i.e., microbicide) such as tuberculosis, HIV-1, or sexually transmitted diseases.
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Role of novel type I interferon epsilon in mucosal immunity. Retrovirology 2012. [PMCID: PMC3441604 DOI: 10.1186/1742-4690-9-s2-p192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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P88 Ulipristal acetate (UPA) is affordable as emergency contraception (EC) if used where levonorgestrel (LNG) is unlicensed. Br J Vener Dis 2012. [DOI: 10.1136/sextrans-2012-050601c.88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Cytokine profile and induction of T helper type 17 and regulatory T cells by human peripheral mononuclear cells after microbial exposure. Clin Exp Immunol 2012; 167:282-95. [PMID: 22236005 DOI: 10.1111/j.1365-2249.2011.04496.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The immunomodulatory effects of probiotics were assessed following exposure of normal peripheral blood mononuclear cells (PBMC), cord blood cells and the spleen-derived monocyte/macrophage cell line CRL-9850 to Lactobacillus acidophilus LAVRI-A1, Lb. rhamnosus GG, exopolysaccharides (EPS)-producing Streptococcus thermophilus St1275, Bifidobacteriun longum BL536, B. lactis B94 and Escherichia coli TG1 strains. The production of a panel of pro- and anti-inflammatory cytokines by PBMC following bacterial stimulation was measured, using live, heat-killed or mock gastrointestinal tract (GIT)-exposed bacteria, and results show that (i) all bacterial strains investigated induced significant secretion of pro- and anti-inflammatory cytokines from PBMC-derived monocytes/macrophages; and (ii) cytokine levels increased relative to the expansion of bacterial cell numbers over time for cells exposed to live cultures. Bifidobacteria and S. thermophilus stimulated significant concentrations of transforming growth factor (TGF)-β, an interleukin necessary for the differentiation of regulatory T cells (T(reg) )/T helper type 17 (Th17) cells and, as such, the study further examined the induction of Th17 and T(reg) cells after PBMC exposure to selected bacteria for 96 h. Data show a significant increase in the numbers of both cell types in the exposed populations, measured by cell surface marker expression and by cytokine production. Probiotics have been shown to induce cytokines from a range of immune cells following ingestion of these organisms. These studies suggest that probiotics' interaction with immune-competent cells produces a cytokine milieu, exerting immunomodulatory effects on local effector cells, as well as potently inducing differentiation of Th17 and T(reg) cells.
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Abstract
Using Toll-like receptor (TLR) and MyD88 gene knock-out (GKO) mice the effect of TLRs and MyD88 on virus replication, interferon (IFN)-β production, natural killer (NK) cell and CD8T cell responses were assessed following ectromelia virus (ECTV) and recombinant vaccinia virus (rVV) infection. The capacity for rVVs encoding cytokines to restore immune function in MyD88(-/-) mice was clearly demonstrated. Results showed that TLR2(-/-), TLR4(-/-)and TLR7(-/-) mice survived ECTV infection whereas MyD88(-/-) and TLR9(-/-)mice, in contrast, were highly susceptible. Next, following infection with rVV, MyD88(-/-) mice elicited reduced serum IFN-β, NK cell and CD8T cell responses compared with wild-type mice, whereas TLR9(-/-) mice showed elevated CD8T cell responses. When MyD88(-/-)mice were infected with rVV co-expressing IFN-β these mice were able to restore IFN-β levels and CD8T cell responses but not NK cell activation. Interestingly, even though rVV co-expressing interleukin (IL)-2 enhanced NK cell activation in MyD88(-/-) mice, this was not associated with an antiviral effect, as observed in normal mice. Surprisingly, co-infection with rVV IL-2/rVV IL-12, but not rVV IL-2/rVV IFN-β, restored the attenuated phenotype of rVV IL-2 in MyD88(-/-) mice indicating that the IL-2/IL-12 combination promotes antiviral responses. Our results clearly show that the CD8T cell defect observed in MyD88(-/-) mice to vaccinia virus infection can be restored by rVV-encoding IFN-β demonstrating the critical role of this cytokine in T cell mediated immunity and illustrates that the model can provide an effective platform for the elucidation of cytokine immunobiology.
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Differential effects of the type I interferons alpha4, beta, and epsilon on antiviral activity and vaccine efficacy. THE JOURNAL OF IMMUNOLOGY 2008; 180:7158-66. [PMID: 18490714 DOI: 10.4049/jimmunol.180.11.7158] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The type I IFNs exert a range of activities that include antiviral, antiproliferative, and immunomodulatory effects. To study this further, we have constructed recombinant vaccinia viruses expressing HIV or hemagglutinin (HA) Ags along with murine type I IFNs, IFN-alpha(4) (HA-VV-IFN-alpha(4)), IFN-beta (HA-VV-IFN-beta), or IFN-epsilon (HIV-VV-IFN-epsilon), a recently discovered member of this family. Our aims were to characterize IFN-epsilon functionality as a type I IFN and also to study the biological properties of these factors toward the development of safer and more effective vector-based vaccines. HIV-VV-IFN-epsilon and HA-VV-IFN-beta grew to lower titers than did their parental controls in murine cell lines. In vivo, however, HIV-VV-IFN-epsilon growth was not attenuated, while IFN-beta demonstrated potent local antiviral activity with no replication of HA-VV-IFN-beta detected. Flow cytofluorometric analysis of B lymphocytes incubated with virally encoded IFN-epsilon showed up-regulation of activation markers CD69 and CD86, while RT-PCR of IFN-epsilon-treated cells revealed that gene expression levels of antiviral proteins were elevated, indicating the induction of an antiviral state. The use of these constructs in a poxvirus prime-boost immunization regime led to robust humoral and cellular immune responses against the encoded Ags, despite the lack of replication in the case of HA-VV-IFN-beta. Thus, coexpression of these factors may be beneficial in the design of safer vector-based vaccines. Our data also indicate that while IFN-epsilon exhibits certain biological traits similar to other type I IFNs, it may also have a specific role in mucosal immune regulation that is quite distinct.
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Abstract
Lentiviral vectors, so far, have been optimized for the expression of a single open reading frame. Certain practical applications of gene therapy will, however, require expression of multiple genes. The goal of this study was to explore the feasibility of directing expression of two marker genes from a lentiviral vector. We designed two types of multigene lentiviral vectors. First, we used a strategy based on the natural splicing signals of HIV-1, by which multiple mRNAs are generated from a single transcriptional unit. A second strategy was construction of a polycistronic mRNA using a translational cis-acting element, the encephalomyocarditis virus internal ribosome entry site (IRES). Our studies show that the inclusion of multiple genes in lentiviral vectors does not result in reduction in virus titers or in the loss of ability to infect nondividing cells. We introduced mutations in tat and/or rev to test whether splicing modulates the relative levels of expression of reporter genes. We also developed a truncated version of tat, which is devoid of the apoptosis-associated domain. Inclusion of this tat mutant in a lentiviral vector resulted in the generation of virus with titers similar to those of lentivirus vectors expressing wild-type tat.
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MESH Headings
- Alternative Splicing/genetics
- Cell Division
- Encephalomyocarditis virus/genetics
- Flow Cytometry
- Gene Expression Regulation, Viral
- Gene Products, tat/chemistry
- Gene Products, tat/genetics
- Genes/genetics
- Genes, Reporter/genetics
- Genes, rev/genetics
- Genes, tat/genetics
- Genetic Vectors/genetics
- HIV-1/genetics
- HeLa Cells
- Humans
- Lentivirus/genetics
- Lentivirus/physiology
- Microscopy, Fluorescence
- Mutation/genetics
- Protein Biosynthesis/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Regulatory Sequences, Nucleic Acid/genetics
- Ribosomes/metabolism
- Transcriptional Activation
- Transduction, Genetic/methods
- Transgenes/genetics
- tat Gene Products, Human Immunodeficiency Virus
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Abstract
Gene therapy against HIV infection should involve vector-mediated delivery of anti-HIV therapeutic genes into T-lymphocytes and macrophages or, alternatively, hematopoietic progenitors. Transduction of mature cells with defective vectors would have limited success because the vector would disappear with cell turnover. However, if a vector could be trafficked by wild-type HIV, initial transduction of a majority of the population would not be required, as the vector would be able to spread. We describe HIV-1-based lentiviral vectors that are efficiently packaged and trafficked by HIV-1, allowing a small number of cells initially transduced to spread the vector within a nontransduced cell population. We examined whether the presence or absence of the rev gene and the Rev-responsive element (RRE) would have a noticeable effect on the ability of lentiviral vectors to be trafficked and to inhibit HIV-1 replication. We found that replacement of rev/RRE with a constitutive transport element from Mason-Pfizer monkey virus had no apparent effect on trafficking and did not change the intrinsic inhibitory abilities of the vectors. We also constructed a rev/RRE-independent HIV-1-derived vector carrying a trans-dominant negative mutant of HIV-1 Rev, RevM10. This vector was less efficiently trafficked by HIV-1 and, despite the presence of an anti-HIV-1 gene, RevM10, was less efficient at inhibiting HIV-1 replication when introduced into a target T-cell population.
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Targeting services to chronically disabled elderly: the preliminary experiences of the National Long Term Care Channeling Demonstration. Home Health Care Serv Q 2001; 6:57-79. [PMID: 10311446 DOI: 10.1300/j027v06n02_05] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In response to concerns about the adequate provision of long term care, the National Long Term Care Channeling Demonstration has been funded by the Department of Health and Human Services. The project is designed to provide coordinated community services as an alternative to institutionalization to those elderly individuals at risk of placement. This preliminary work examines the demonstration's experience in its attempt to target services to these individuals. Although final research results are not yet available, the method, problems, and results of the initial case finding and screening approaches provide additional knowledge concerning the targeting experience.
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Assistive technology for postsecondary students with learning disabilities. JOURNAL OF LEARNING DISABILITIES 1996; 29:486-503. [PMID: 8870518 DOI: 10.1177/002221949602900503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
An increasing number of students with learning disabilities are attending postsecondary institutions. To meet the educational demands of these students, support service providers will likely rely on assistive technology. This article lists types of assistive technology appropriate for use with persons with learning disabilities at the postsecondary level and discusses ways in which assistive technology enhances learning. Additionally, an overview of legislation that has had an impact on assistive technology at the postsecondary level is presented. Issues involving assistive technology programs at the postsecondary level are discussed. Postsecondary assistive technology program components, device selection, and training guidelines also are outlined.
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Abstract
The characteristics and outcome of pregnancy complicated by gestational glucose intolerance are described in a consecutive series of 69 Bengali Asian patients and a parallel group of 22 Caucasian patients. The Bengali patients were older and of higher parity than the Caucasians and more frequently required insulin therapy. However, the outcome of pregnancy was similar in terms of antenatal clinic attendance, the number of antenatal hospital admissions, glycaemic control, birthweight and mode of delivery. Of those patients who attended for postnatal glucose tolerance test, 20% of the Bengali population demonstrated persisting abnormality of glucose tolerance, whereas no abnormalities were evident in the Caucasian group. These findings are consistent with the high prevalence and early age of onset of non-insulin-dependent diabetes in Asian populations. The World Health Organisation (WHO) criteria for the diagnosis of impaired glucose tolerance proved insufficiently sensitive for the diagnosis of gestational diabetes. This was particularly demonstrated by four patients with apparently normal glucose tolerance by WHO criteria who subsequently required insulin therapy.
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Abstract
This study examined perceptual differences in symmetry with and without a model between 21 learning disabled boys with reading deficits and 28 learning disabled boys with deficits in mathematics. 55 nonlearning disabled boys served as controls. All boys were in Grades 3, 4, or 5. Without a model, all learning disabled boys built significantly more asymmetrical building block designs than nonlearning disabled boys. However, with a model, all learning disabled boys could imitate the model, but it took them longer to complete the task successfully. All boys appeared to have difficulty in modeling asymmetrical tasks, taking more time for task completion after seeing an asymmetrical model. This study suggests modeling perceptual tasks might be an effective teaching strategy for such children.
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Effect of estradiol withdrawal on luteal hormone responsive adenylyl cyclase and luteal function in the pseudopregnant rabbit. Biol Reprod 1980; 22:791-7. [PMID: 7397301 DOI: 10.1095/biolreprod22.4.791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Effect of prolactin on luteal functions in the cyclic rat: positive correlation between luteinizing hormone-stimulated adenylyl cyclase activity and progesterone secretion; role in corpus luteum rescue of the morning surge of prolactin on day 3 of pseudopregnancy. Endocrinology 1980; 106:1265-9. [PMID: 7188902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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The effect of estradiol on hormonally stimulable adenylyl cyclase activity and on progesterone production in normal and regressing corpora lutea from control and human chorionic gonadotropin-treated pseudopregnant rabbits. Endocrinology 1980; 106:375-81. [PMID: 7349969 DOI: 10.1210/endo-106-1-375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Corpus luteum function and adenylyl cyclase stimulability in the rat after an estradiol benzoate-induced ovulatory surge of luteinizing hormone: role of prolactin. Endocrinology 1980; 106:382-9. [PMID: 7188603 DOI: 10.1210/endo-106-1-382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Ovarian responses of pregnant mare serum gonadotropin- and human chorionic gondotropin-primed rats: desensitizing, luteolytic, and ovulatory effects of a single dose of human chorionic gonadotropin. Endocrinology 1979; 105:442-51. [PMID: 456322 DOI: 10.1210/endo-105-2-442] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We conducted a study to determine the morphological appearance and functional responsiveness of ovarian tissues after administration of hCG to 28-day-old rats primed 65 h earlier with PMS gonadotropin (PMSG) and after administration of a second dose of hCG 5 days later, i.e. to 33-day-old rats containing heavily luteinized ovaries. Sixty-five hours after the administration of 50 IU PMSG sc to 25-day-old rats, ovaries already contained an abundance of luteinized follicles and an adenylyl cyclase (AC) system that was responsive to LH, epinephrine, and NaF. The administration of 50 IU hCG sc at this time initially resulted in a loss of LH-responsive ovarian AC. Within 4 days of the hCG injection, the ovaries of the now 32-day-old rats were heavily luteinized, and ovarian AC was highly responsive to LH, epinephrine, and NaF. The administration of a single sc dose of 200 IU hCG to 33-day-old PMSC- and hCG-primed rats with luteinized ovaries resulted in a rapid desensitization of the ovarian AC to LH and a drop in serum progesterone levels, During the subsequent 7 days, serum progesterone levels continued to decline, while total ovarian AC reacquired responsiveness to LH by days 4--5 after the densensitizing dose of hCG. Dissection of ovarian components revealed, however, that the AC system of the corpora lutea originally present at the time of the second hCG injection remained permanently refractory to LH and that the AC in corpora lutea newly formed from freshly ovulated follicles exhibited a significant responsiveness to LH, epinephrine, and NaF. However, these new corpora lutea were not fully active, since serum progesterone never rose. Subcutaneous administration of 50 IU hCG to 33-day-old PMSG- and hCG-primed rats also promoted a rapid loss of AC responsiveness to LH. This lower concentration of hCG was not sufficient to promote follicular development or ovulation, and the ovarian AC remained refractory to LH for at least 7 days. Intravenous administration of 75 IU hCG to 33-day-old PMSG- and hCG-primed rats similarly promoted a rapid and permanent loss of luteal AC responsiveness to LH; again, follicles did not mature to a preovulatory state and, in fact, appeared to undergo atresia rather than ovulation. These results indicate that in heavily luteinized ovaries 1) hCG promotes desensitization of rat luteal AC to LH, 2) Desensitization of AC to LH stimulation in corpora lutea is permanent and irreversible, and 3) only under conditions where follicles mature and ovulate and new corpora lutea are formed does total ovarian AC reacqure responsiveness during the subsequent week.
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Presence of prostaglandin F (PGF) in hen follicles and its physiological role in ovulation and oviposition. Biol Reprod 1977; 16:486-94. [PMID: 857943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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