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OBJECTIVE: to identify the factors associated with student withdrawal during their university training. DESIGN: an Internet-based survey questionnaire was designed and administered. SETTING: two universities in Ontario, Canada. PARTICIPANTS: senior level students in years three and four, graduates of the programme and those students that withdrew prior to graduation. FINDINGS: students who withdrew from the programme were more likely to report not feeling academically supported and not being prepared for the time commitments required. Students with the greatest risk for leaving the programme were those that took a leave of absence, over half of which were maternity leaves. CONCLUSION: having identified those significant factors associated with student attrition, we can now begin to develop specific interventions to improve retention rates.
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Educación de Postgrado en Enfermería/organización & administración , Partería/educación , Abandono Escolar/estadística & datos numéricos , Estudiantes de Enfermería/estadística & datos numéricos , Adulto , Selección de Profesión , Recolección de Datos , Femenino , Humanos , Masculino , Ontario , Permiso Parental/estadística & datos numéricos , Embarazo , Factores de Riesgo , Encuestas y Cuestionarios , UniversidadesAsunto(s)
Células de la Granulosa/metabolismo , Resistina/biosíntesis , Adulto , Western Blotting , Femenino , Fármacos para la Fertilidad Femenina/uso terapéutico , Expresión Génica/fisiología , Humanos , Inmunohistoquímica , Infertilidad Femenina/metabolismo , Infertilidad Femenina/terapia , Leuprolida/uso terapéutico , Recuperación del Oocito , PPAR gamma/biosíntesis , PPAR gamma/genética , ARN/biosíntesis , ARN/genética , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Resistina/genéticaRESUMEN
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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The receptors for members of the relaxin peptide family have only recently been discovered and are G-protein-coupled receptors (GPCRs). Relaxin and insulin-like peptide 3 (INSL3) interact with the leucine-rich-repeat-containing GPCRs (LGRs) LGR7 and LGR8, respectively. These receptors show closest similarity to the glycoprotein hormone receptors and contain large ectodomains with 10 leucine-rich repeats (LRRs) but are unique members of the LGR family (class C) as they have an LDL class A (LDLa) module at their N-terminus. In contrast, relaxin-3 and INSL5 interact with another class of type I GPCRs which lack a large ectodomain, the peptide receptors GPCR135 and GPCR142, respectively. These receptors are now classified as relaxin family peptide (RXFP) receptors, RXFP1 (LGR7), RXFP2 (LGR8), RXFP3 (GPCR135) and RXFP4 (GPCR142). This review outlines the identification of the peptides and receptors, their expression profiles and physiological roles and the functional interactions of the peptides with their unique receptors.
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Membrana Celular/metabolismo , Receptores de Péptidos/química , Receptores de Péptidos/metabolismo , Relaxina/química , Relaxina/metabolismo , Secuencia de Aminoácidos , Animales , Humanos , Datos de Secuencia MolecularRESUMEN
OBJECTIVE: To correlate the temporal expression of transforming growth factor-alpha (TGF-alpha) and TGF-beta genes in granulosa cells (GC) and thecal cells from human follicles at various developmental stages and to determine their trophic effects on GCs. DESIGN: Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of extracted RNA from follicular GCs and theca cells. SETTING: Academic endocrinology laboratory. PATIENT(S): Premenopausal women undergoing total abdominal hysterectomy and bilateral salpingo-oophorectomy for nonovarian reasons. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Confirmation by the RT-PCR product for TGF-alpha and TGF-beta gene expression in GC and theca cells from human follicles at various developmental stages and (3)H-thymidine uptake in vitro to assess growth effects on GCs. RESULT(S): The RT-PCR product indicating the presence of TGF-alpha messenger RNA (mRNA) was found consistently in theca from healthy antral follicles. In theca from large follicles (>1.0 cm) the TGF-alpha PCR product was of reduced intensity. The TGF-alpha was absent or undetectable in granulosa cells from all follicle sizes. The PCR product for TGF-beta was generated by all GC and thecal cell RNAs from all follicle sizes examined. The TGF-alpha promoted and TGF-beta inhibited human GC growth. CONCLUSION(S): The presence of TGF-alpha gene expression in thecal cells coincides with periods of follicular growth. The expression of TGF-beta occurs in both cell types throughout antral follicle development. The TGF-alpha and TGF-beta have opposing trophic effects on GCs.
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Folículo Ovárico/crecimiento & desarrollo , Folículo Ovárico/metabolismo , Factor de Crecimiento Transformador alfa/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Adulto , Diferenciación Celular , Proliferación Celular , Femenino , Regulación de la Expresión Génica , Células de la Granulosa/citología , Células de la Granulosa/metabolismo , Humanos , Células Lúteas/citología , Células Lúteas/metabolismo , ARN Mensajero/metabolismo , Factor de Crecimiento Transformador alfa/genética , Factor de Crecimiento Transformador beta/genéticaRESUMEN
Progesterone is produced by granulosa cells under the influence of luteinizing hormone. Nuclear progesterone receptors have been found in rat granulosa cells. Human granulosa-lutein cells rapidly respond to progesterone with an increase in intracellular calcium suggesting the existence of a nongenomic mechanism. This study was conducted to determine whether binding of progesterone to granulosa cells could occur at the membrane. Granulosa cells were obtained from an in vitro fertilization program and examined immunohistochemically with an antiserum to membrane progesterone receptors. Approximately 14-70% of freshly harvested or cultured granulosa cells of six patients showed a positive reaction to the antiserum, limited to the cell membrane. Western blot analysis of homogenates of granulosa cells and a granulosa cell tumour confirmed the presence of progesterone receptors A, B and C and low amounts of a putative membrane receptor. These results demonstrate that the plasma membranes of human granulosa cells possess binding components for progesterone which may be involved in its nongenomic mechanism of action.
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Células de la Granulosa/metabolismo , Luteína/metabolismo , Progesterona/metabolismo , Sitios de Unión , Western Blotting , Membrana Celular/metabolismo , Femenino , HumanosRESUMEN
PURPOSE: To validate an expedited method for the removal of erythrocytes when preparing IVF granulosa-luteal cells for culture. METHODS: Granulosa cells were enriched for culturing from follicular aspirates by density gradient centrifugation and by hypo-osmotic lysis treatments. RESULTS: Cells prepared by either method showed the same cell viability and produced progesterone in similar quantities. CONCLUSIONS: Using hypo-osmotic lysis to remove erythrocytes does not impair granulosa cell viability or steroidogenesis. It avoids multiple density gradient centrifugations and washings, and yields IVF granulosa cells ready for culture efficiently.
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Técnicas de Cultivo de Célula/métodos , Fertilización In Vitro , Células de la Granulosa/citología , Supervivencia Celular , Femenino , Líquido Folicular/citología , HumanosRESUMEN
One of the most misunderstood concepts in progressive educational curricula is that of problem-based learning (PBL). Often confused with problem solving, the two are quite different. Courses conducted in a PBL format use problems as a launch pad for resulting study. This article reviews a course designed to enable students to learn and understand the principles of human reproductive physiology using PBL. The learning process is situation based, student directed, and takes place in small groups. The rationale for some of these innovations is discussed and the way in which they were implemented is described.