45 results on '"Stojanov T"'
Search Results
2. O-277 Development of novel automated vitrification instrument; confirmation of ability to control critical parameters in a microfluidics consumable and software controlled instrument as part of vitrification
- Author
-
Vom, E., Roy, T.K., Brandi, S., Tappe, N.M., Peura, T.T., McArthur, S.J., and Stojanov, T.
- Published
- 2013
3. O-155 Novel automated instrument executing a standardised closed vitrification protocol yields equivalent outcomes with human blastocysts when compared with open manual vitrification system
- Author
-
Roy, T.K., Brandi, S., Tappe, N.M., Vom, E., Peura, T.T., McArthur, S.J., Bowman, M.C., and Stojanov, T.
- Published
- 2013
4. Profil clinique et trajectoires de soins des résidents bénéficiant de l’intervention mixte hospitalisation à domicile–établissement d’hébergement pour personnes âgées dépendantes à Paris, France
- Author
-
Stojanov, T., primary, Georges, A., additional, and De Stampa, M., additional
- Published
- 2020
- Full Text
- View/download PDF
5. Orthographic Lexicography and Its Aspects in Online Dictionary Portals
- Author
-
Stojanov T
- Subjects
Computer science ,business.industry ,Online dictionary ,Orthographic projection ,linguistics ,Artificial intelligence ,computer.software_genre ,business ,computer ,Natural language processing ,Lexicography - Abstract
This short paper raises and answers a question related to orthographic lexicography in general and its reference to efforts in making contemporary dictionary portals. As orthographic dictionaries have not yet been researched as a specialized lexicographic variety, part of their metalexicographic description in those European languages that have online normative orthographic dictionaries is presented. Metalexicographic elements that are analyzed were chosen from the perspective of casual and professional users and online dictionary visitors. Regardless of the fact that this is a specific kind of dictionary, as well as of the fact that European orthographic tradition and practice is quite heterogeneous, the belief that the European Dictionary Portal should also include available online orthographic dictionaries is defended. An argument in favor of this could contribute to an awareness of the importance of orthography for online dictionary users, even in those languages whose written form greatly corresponds to the spoken form.
- Published
- 2018
6. Orthographic Literacy as Methodological Guideline for Orthographic Standardization
- Author
-
Stojanov T
- Subjects
Standardization ,Methodological guideline ,media_common.quotation_subject ,Orthographic projection ,linguistics ,Psychology ,Linguistics ,Literacy ,media_common - Abstract
This paper discusses the impact of orthographic manuals on the state of literacy, i.e. the relation of orthographic literacy and orthographic standardisation. The established hypothesis claims that frequent changes of orthographic rules during the pupils’ primary and secondary education do not have any considerable impact on their orthographic habits. In other words, the quantity of orthographic mistakes observed during a longer period of time and in conditions of changed orthographic rules would not show significant oscillations in their spelling. In order to confirm the hypothesis, a questionnaire was conducted encompassing 41 tests among 526 students of a technical study programme during four consecutive academic years, pursuant to whose results a writing uniformity index and a categorisation of orthographic controversy into six classes is established. The Croatian language has been selected for the observation due to multiple orthographic changes in the last 30 years in the three major orthographic points: writing of the covered r, writing of d and t in front of c and č in declination of words ending in -tak, -tac, -dak and -dac, and the issue of compound or separate spelling of the negation particle and the auxiliary biti (to be). Moreover, the paper methodologically and quantitatively establishes criteria according to which the second established hypothesis on evolutionary orthographic literacy can be confirmed. The conclusions are expected to be able to contribute to the better understanding of orthographic planning and application of orthographic norms in schools.
- Published
- 2018
7. Flow cytometric sorting of fresh and frozen-thawed spermatozoa in the western lowland gorilla
- Author
-
O'Brein, J.K., Maxwell, W.M.C., Stojanov, T., Evans, G., Crichton, E.G., Loskutoff, N.M., Evans, K.M., and Leigh, D.
- Subjects
Gorillas -- Research ,Spermatozoa -- Research ,Anthropology/archeology/folklore ,Biological sciences ,Health ,Psychology and mental health - Abstract
A study was performed to develop the methodologies for liquid storage of semen prior to sorting, sorting of liquid-stored and frozen-thawed spermatozoa and assessment of sorting accuracy on gorillas. The results demonstrated that fresh or frozen-thawed gorilla spermatozoa could be flow cytometrically sorted into samples, enriched for X-bearing spermatozoa.
- Published
- 2005
8. Session 41: Keys for success for embryo cryopreservation
- Author
-
Murakami, M., primary, Egashira, A., additional, Tanaka, K., additional, Mine, C., additional, Kuramoto, T., additional, Van Landuyt, L., additional, Van de Velde, H., additional, De Vos, A., additional, Haentjens, P., additional, Blockeel, C., additional, Tournaye, H., additional, Verheyen, G., additional, Papatheodorou, A., additional, Panagiotidis, Y., additional, Petousis, S., additional, Kasapi, E., additional, Goudakou, M., additional, Passadaki, T., additional, Prapas, N., additional, Vanderzwalmen, P., additional, Zikopoulos, K., additional, Georgiou, I., additional, Prapas, Y., additional, Abuzeid, M., additional, Ahmed, F. A., additional, Abozaid, T., additional, Urich, M., additional, Ullah, K., additional, Salem, H., additional, Sasy, M., additional, Khan, I., additional, Roy, T. K., additional, Brandi, S., additional, Tappe, N. M., additional, Vom, E., additional, Peura, T. T., additional, McArthur, S. J., additional, Bowman, M. C., additional, and Stojanov, T., additional
- Published
- 2013
- Full Text
- View/download PDF
9. Session 70: Challenges in cryopreservation
- Author
-
Potdar, N., primary, Gelbaya, T. A., additional, Nardo, L. G., additional, Bos-Mikich, A., additional, Aquino, D., additional, Danielli, L., additional, Rigon, P. S. L., additional, Lothhammer, N., additional, Frantz, N., additional, Desai, N., additional, Austin, C., additional, Goldberg, J., additional, Falcone, T., additional, Trapphoff, T., additional, Staubach, N., additional, Seidel, T., additional, Heiligentag, M., additional, Eichenlaub-Ritter, U., additional, Vom, E., additional, Roy, T. K., additional, Brandi, S., additional, Tappe, N. M., additional, Peura, T. T., additional, McArthur, S. J., additional, and Stojanov, T., additional
- Published
- 2013
- Full Text
- View/download PDF
10. Chromosomes from embryonic cells: a cytogenetic analysis
- Author
-
Leigh, D, primary, Chami, O, additional, Dumevska, B, additional, Wright, D, additional, Texlova, K, additional, and Stojanov, T, additional
- Published
- 2008
- Full Text
- View/download PDF
11. P-206
- Author
-
Costigan, S., primary, Henman, M., additional, and Stojanov, T., additional
- Published
- 2006
- Full Text
- View/download PDF
12. ASCR-011 Human embryonic stem cell lines from PGD-analysed embryos
- Author
-
Stojanov, T, primary, Peura, T, additional, Bosman, A, additional, Texlova, K, additional, and Jansen, R, additional
- Published
- 2006
- Full Text
- View/download PDF
13. 304 PRODUCTION OF PORCINE EMBRYOS OF A PREDETERMINED SEX AFTER IN VITRO FERTILIZATION OF IN VITRO-MATURED OOCYTES WITH SEX-SORTED FROZEN-THAWED BOAR SPERM
- Author
-
Bathgate, R., primary, Morton, K.M., additional, Eriksson, B.M., additional, Rath, D., additional, Seig, B., additional, Chami, O., additional, Stojanov, T., additional, Maxwell, W.M.C., additional, and Evans, G., additional
- Published
- 2005
- Full Text
- View/download PDF
14. Flow Cytometric Sorting of Fresh and Frozen-Thawed Spermatozoa in the Western Lowland Gorilla (Gorilla gorilla gorilla)
- Author
-
O'Brien, J.K., primary, Stojanov, T., additional, Crichton, E.G., additional, Evans, K.M., additional, Leigh, D., additional, Maxwell, W.M.C., additional, Evans, G., additional, and Loskutoff, N.M., additional
- Published
- 2005
- Full Text
- View/download PDF
15. 176 IMPROVED GROWTH OF HUMAN EMBRYONIC STEM CELLS IN A REDUCED OXYGEN ATMOSPHERE
- Author
-
Peura, T., primary, Bosman, A., additional, and Stojanov, T., additional
- Published
- 2005
- Full Text
- View/download PDF
16. 240.Fertilisation in vitro causes precocious activation of transcription from the zygotic genome
- Author
-
O'Neill, C., primary and Stojanov, T., additional
- Published
- 2004
- Full Text
- View/download PDF
17. In Vitro Fertilization Causes Epigenetic Modifications to the Onset of Gene Expression from the Zygotic Genome in Mice1
- Author
-
Stojanov, T., primary and O’Neill, C., additional
- Published
- 2001
- Full Text
- View/download PDF
18. Ontogeny of Expression of a Receptor for Platelet-Activating Factor in Mouse Preimplantation Embryos and the Effects of Fertilization and Culture In Vitro on Its Expression1
- Author
-
Stojanov, T., primary and O'Neill, C., additional
- Published
- 1999
- Full Text
- View/download PDF
19. In-vitro fertilization and culture of mouse embryos in vitro significantly retards the onset of insulin-like growth factor-II expression from the zygotic genome
- Author
-
Stojanov, T., primary
- Published
- 1999
- Full Text
- View/download PDF
20. Liquid storage of ram semen in the absence or presence of some antioxidants
- Author
-
Maxwell, WM, primary and Stojanov, T, additional
- Published
- 1996
- Full Text
- View/download PDF
21. In vitro fertilisation with chilled-stored ram spermatozoa
- Author
-
Stojanov, T., primary, Robinson, S.J., additional, Rhodes, S.L., additional, O'Brien, J.K., additional, Evans, G., additional, and Maxwell, W.M.C., additional
- Published
- 1994
- Full Text
- View/download PDF
22. P-206: Non-immersion vitrification - a viable alternative to slow freezing of blastocysts
- Author
-
Costigan, S., Henman, M., and Stojanov, T.
- Published
- 2006
- Full Text
- View/download PDF
23. Variable expressivity of the tumour suppressor protein TRP53 in cryopreserved human blastocysts
- Author
-
Stojanov Tomas, Chami Omar, Chandrakanthan Vashe, and O'Neill Chris
- Subjects
Gynecology and obstetrics ,RG1-991 ,Reproduction ,QH471-489 - Abstract
Abstract In a mouse model, in vitro fertilization or extended embryo culture leads to the increased expression of TRP53 in susceptible embryos. Ablation of the TRP53 gene improved embryo viability indicating that increased expression of TRP53 is a cause of the reduction of embryo viability resulting from in vitro fertilization or embryo culture. This study investigates the status of TRP53 expression in human embryos produced by intracytoplasmic sperm injection. Following fertilization, embryos were cultured for 96 h and then cryopreserved. Immediately upon thawing they were fixed in formaldehyde and subjected to immunostaining for TRP53. Staining was visualized by confocal microscopy. Negative controls were incubated with isotype control immunoglobulin and showed negligible staining. All embryos showed TRP53 staining above negative controls. TRP53 staining was heterogenous within and between embryos. An embryo that showed retarded development showed high levels of TRP53 expression. A blastocyst that had a collapsed blastocoel also showed high levels of TRP53 compared to morphologically normal blastocysts. Most TRP53 staining was in the region of the nucleus. Morphologically normal blastocysts tended to show little nuclear accumulation of stain. However, some cells within these embryos had high levels of nuclear TRP53 expression. The results show that embryos have varying sensitivity to the stresses of production and culture in vitro, and this resulted in variable expressivity of TRP53.
- Published
- 2007
- Full Text
- View/download PDF
24. 176 IMPROVED GROWTH OF HUMAN EMBRYONIC STEM CELLS IN A REDUCED OXYGEN ATMOSPHERE
- Author
-
Peura, T., Bosman, A., and Stojanov, T.
- Abstract
Traditional cell culture conditions entail the use of gas atmosphere consisting of 5?6% CO2 in air. These same conditions have also been used universally for the culture of human embryonic stem cells (hES), despite the natural milieu of the embryos, from which these cells are derived, being slightly hypoxic. The aim of this work was to examine if human embryonic stem cells would benefit from the reduced oxygen culture environment, as used for human pre-implantation embryos. In Experiment 1, the relative growth in high and low oxygen atmosphere was compared by cutting undifferentiared hES-colonies into equal-size pieces and transferring them to two dishes, one into the conventional incubator in 6% CO2 in air (HIGH), the other into K-MINC-1000 (Eight Mile Plains, Queensland) mini-incubator in 5% O2, 6% CO2 and 89% N2 (LOW). After 8 days the colony sizes and differentiation status were measured. In Experiment 2, the absolute growth in high and low oxygen atmosphere was compared by cutting exactly same size fragments from undifferentiated hES-colonies and distributing them to two treatments as described. All colonies were measured and passaged at Day 7 and final measurements taken at Day 14. In Experiment 1, improved growth was observed in reduced oxygen, mean percentage of undifferentiated growth from original colony (assigned as 100%) being 217% for HIGH and 482% for LOW over three replicates. In Experiment 2, the total of 16.9 mm2 of undifferentiated colonies in both treatment groups (24 colonies per group over 3 replicates) had by Day 7 grown to total of 51.1 and 79.5 mm2 (P < 0.001), and by Day 14 to 216.8 and 373.3 mm2 (P < 0.0001) in HIGH and LOW, respectively (see Table 1). In neither experiment were there differences in the differentiation status of the colonies between the treatments (mean 6% and 5% at Day 7, and 9% and 9% at Day 14 in HIGH and LOW, respectively). We conclude that culture in reduced oxygen improves growth of human embryonic stem cells. We like to acknowledge Bresagen Ltd. for the supply of hesBGN-01 cell line.
- Published
- 2004
- Full Text
- View/download PDF
25. Understanding preoperative health-related quality of life in rotator cuff tear patients: role of patients' characteristics.
- Author
-
Brune D, Stojanov T, Müller AM, Weibel D, Hunziker S, Erdbrink S, and Audigé L
- Subjects
- Humans, Male, Female, Middle Aged, Prospective Studies, Aged, Preoperative Period, Surveys and Questionnaires, Switzerland, Quality of Life, Rotator Cuff Injuries surgery, Rotator Cuff Injuries psychology, Arthroscopy
- Abstract
Background: Assessing health-related quality of life (HRQoL) is a widely employed method in orthopedics to evaluate patient well-being and measure the effectiveness of surgical interventions. Understanding the relationship between specific baseline factors and preoperative HRQoL can help clinicians identify patients at risk for low quality of life and thus, develop preventive strategies that adequately address individual patient needs. The objective was to assess associations between baseline factors and preoperative HRQoL in patients undergoing arthroscopic rotator cuff repair (ARCR)., Methods: This study is part of a multicenter prospective Swiss cohort study that included patients undergoing ARCR between June 2020 and November 2021. Data were derived from baseline and surgery forms. HRQoL was assessed using the European Quality of Life 5-Dimension 5-Level (EQ-5D-5L) questionnaire to calculate EQ-5D index and EQ VAS scores. Univariable and multivariable linear regression models examined associations between the 21 factors and preoperative HRQoL. Final models were determined using stepwise backward regression., Results: A total of 973 included patients (mean age [SD], 57.3 [9.4] years; 611 men [63%]) had a mean [SD] EQ-5D index and EQ VAS of 0.70 [0.23] and 68.7 [19.8], respectively. Being male (regression coefficient (β), 0.05; 95% CI [0.02-0.08]), having a higher age (β, 0.02; 95% CI [0.01-0.03]) and higher education levels (e.g., university, college: β, 0.11; 95% CI [0.06-0.16]) were associated with a higher EQ-5D index. Increased body mass index (β, -0.02; 95% CI [-0.04 to -0.01]) and worse sleep quality (β, -0.03; 95% CI [-0.04 to -0.03]) were associated with a lower EQ-5D index. Factors negatively associated with overall EQ VAS health were depression (e.g., moderate: β, -12.70; 95% CI [-16.18 to -9.21]), presence of at least one comorbidity (β, -3.71; 95% CI [-5.91 to -1.52]), and pain (β, -1.81; 95% CI [-2.36 to -1.26])., Conclusion: Our results suggest that preoperative HRQoL is highly associated with sociodemographic and patient-related factors. Specifically addressing these factors may improve orthopedic care., Competing Interests: Declarations. Ethics approval and consent to participate: This project was carried out in accordance with the protocol and principles enunciated in the current version of the Declaration of Helsinki and guidelines of Good Clinical Practice (GCP) issued by the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) as well as Swiss law and Swiss regulatory authority requirements. Ethics approval was obtained on April 1st, 2020 from the lead ethics committee (Ethikkommission Nordwest- und Zentralschweiz (EKNZ), Basel, Switzerland; ID: 2019-02076) followed by subsequent amendments until December 20th, 2022, associated with the implementation of additional MRI examinations. All participants provided informed written consent before study enrollment . Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
26. Development and internal validation of a model predicting patient-reported shoulder function after arthroscopic rotator cuff repair in a Swiss setting.
- Author
-
Stojanov T, Aghlmandi S, Müller AM, Scheibel M, Flury M, and Audigé L
- Abstract
Background: Prediction models for outcomes after orthopedic surgery provide patients with evidence-based postoperative outcome expectations. Our objectives were (1) to identify prognostic factors associated with the postoperative shoulder function outcome (the Oxford Shoulder Score (OSS)) and (2) to develop and validate a prediction model for postoperative OSS., Methods: Patients undergoing arthroscopic rotator cuff repair (ARCR) were prospectively documented at a Swiss orthopedic tertiary care center. The first primary ARCR in adult patients with a partial or complete rotator cuff tear were included between October 2013 and June 2021. Thirty-two potential prognostic factors were used for prediction model development. Two sets of factors identified using the knowledge from three experienced surgeons (Set 1) and Bayesian projection predictive variable selection (Set 2) were compared in terms of model performance using R squared and root-mean-squared error (RMSE) across 45 multiple imputed data sets using chained equations and complete case data., Results: Multiple imputation using data from 1510 patients was performed. Set 2 retained the following factors: American Society of Anesthesiologists (ASA) classification, baseline level of depression and anxiety, baseline OSS, operation duration, tear severity, and biceps status and treatment. Apparent model performance was R-squared = 0.174 and RMSE = 7.514, dropping to R-squared = 0.156, and RMSE = 7.603 after correction for optimism., Conclusion: A prediction model for patients undergoing ARCR was developed using solely baseline and operative data in order to provide patients and surgeons with individualized expectations for postoperative shoulder function outcomes. Yet, model performance should be improved before being used in clinical routine., (© 2023. BioMed Central Ltd., part of Springer Nature.)
- Published
- 2023
- Full Text
- View/download PDF
27. Reproducibility and Scientific Integrity of Big Data Research in Urban Public Health and Digital Epidemiology: A Call to Action.
- Author
-
Quiroga Gutierrez AC, Lindegger DJ, Taji Heravi A, Stojanov T, Sykora M, Elayan S, Mooney SJ, Naslund JA, Fadda M, and Gruebner O
- Subjects
- Reproducibility of Results, Public Health Practice, Public Health, Big Data
- Abstract
The emergence of big data science presents a unique opportunity to improve public-health research practices. Because working with big data is inherently complex, big data research must be clear and transparent to avoid reproducibility issues and positively impact population health. Timely implementation of solution-focused approaches is critical as new data sources and methods take root in public-health research, including urban public health and digital epidemiology. This commentary highlights methodological and analytic approaches that can reduce research waste and improve the reproducibility and replicability of big data research in public health. The recommendations described in this commentary, including a focus on practices, publication norms, and education, are neither exhaustive nor unique to big data, but, nonetheless, implementing them can broadly improve public-health research. Clearly defined and openly shared guidelines will not only improve the quality of current research practices but also initiate change at multiple levels: the individual level, the institutional level, and the international level.
- Published
- 2023
- Full Text
- View/download PDF
28. Prognostic factors for improvement of shoulder function after arthroscopic rotator cuff repair: a systematic review.
- Author
-
Stojanov T, Audigé L, Modler L, Aghlmandi S, Appenzeller-Herzog C, Loucas R, Loucas M, and Müller AM
- Abstract
Background: The identification of factors that specify prognostic models for postoperative results should be based on the best scientific evidence and expert assessment. We aimed to identify, map, and evaluate potential prognostic factors for the improvement of shoulder function in patients undergoing arthroscopic rotator cuff repair., Methods: Longitudinal primary studies of arthroscopic rotator cuff repair reporting any multivariable factor analyses for shoulder function improvement with an endpoint assessment of at least 6 months were included. We systematically searched EMBASE, Medline, and Scopus for articles published between January 2014 and June 2021. The risk of bias of included studies and the quality of evidence were assessed using the Quality in Prognosis Studies tool and an adapted Grading of Recommendations, Assessment, Development, and Evaluations framework., Results: Overall, 24 studies including 73 outcome analyses were included. We classified younger age and smaller tear size as probably prognostic for a greater improvement in objective outcomes. Shorter symptom duration, absence of a worker compensation claim, low preoperative level of functional status, and high preoperative pain level were classified as probably prognostic for greater improvement in patient-reported outcome measures. The quality of the synthesized evidence was low. Twenty-one studies had an overall high risk of bias., Conclusion: Six potential prognostic factors for shoulder function after arthroscopic rotator cuff repair were identified. Along with ongoing expert opinion assessments, they will feed into a prognostic model-building process., (© 2022 The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
29. From psychiatric hospitals to residential facilities: Characteristics of patients who benefited from an institutional partnership.
- Author
-
Stojanov T, Perquier F, Boiteux C, Soudani MLN, Château N, Perozziello A, and Gallarda T
- Subjects
- Aged, Cross-Sectional Studies, Hospitalization, Humans, Residential Facilities, Cognition Disorders, Hospitals, Psychiatric
- Abstract
Objectives: The population of older adults is growing fast, especially in Europe and Northern America. Old age is often associated with mental health comorbidities. Moreover, life expectancy of people suffering from psychiatric disorders has increased, but with age-related difficulties, such as loss of independence. This represents a challenge for public health policies, as this population requires specific care and living conditions. As a response, a convention was signed between living facilities for dependent elderly (EHPAD) and the GHU Paris Psychiatry and Neurosciences. The agreement included dedicated places in EHPAD for older patients with psychiatric disorders. The aim of the study was to describe the sociodemographic and clinical characteristics of those patients., Methods: We conducted a cross-sectional study among patients who applied for an EHPAD admission., Results: Between 2016 and 2019, 163 patients applied for placement in an EHPAD, and 117 were admitted (72%). Applicants were 71 years old on average. Admitted patients were older than non-admitted and lived in different Parisian sectors. Among admitted patients, nine in 10 were single, divorced or widowed, and 64.3% were childless. Almost half of them were schizophrenic or had delusional disorders (46.9%), and 65.3% were considered as moderately dependent. At the time of the study, 89 patients still lived in EHPAD. Almost half of them had anxiety and depressive disorders (48.3%), 19.1% had cognitive disorders, and 42.7% manifested agitation., Conclusions: Our study highlighted older psychiatric patients' specificities regarding their admission status into long-term living facilities., (© 2022 John Wiley & Sons Ltd.)
- Published
- 2022
- Full Text
- View/download PDF
30. Clinical profile and care pathways of nursing home residents having the intervention of hospital at home and comparison according to the referrers
- Author
-
Stojanov T, Georges A, and De Stampa M
- Subjects
- Aged, 80 and over, Female, Hospitalization, Hospitals, Humans, Male, Retrospective Studies, Critical Pathways, Nursing Homes
- Abstract
Background: Nursing homes’ (NH) residents present a mix of medical, psychological and social needs associated with a high risk of hospitalization. The intervention of the hospitalization at home (HAH) in NH has been implemented in France to better fit the residents’ needs and decrease the risk of hospitalization. No study has described the population of residents receiving this intervention. This study aimed to define the profile and the care pathway of residents and compare their characteristics according to the referrals (NH or hospitals)., Methods: A retrospective study on 1,436 residents’ stays in the intervention of the Assistance Publique-Hôpitaux de Paris’HAH in Ile de France between 2014 and 2019 was implemented. The Programme de Médicalisation des Systèmes d’Information (PMSI) data was used for the analysis., Results: Residents were 88 years old with 69 % of women with functional disability and the care was mainly represented by the complex dressing (68 %). For the care pathway, 65 % of the referrers were from the NH and 35 % from the hospital settings, 33 % of the residents died at the end of the stay in the NH and 25 % were transferred to hospitals. When the referrer was the hospital, the residents were mainly men (p < 0.001), younger (p < 0.001), receiving more often intravenous treatment and palliative care (p < 0.01) with a higher level of indice of Karnofsky (p < 0.01). When the NH was the referrer, deaths were more frequent, whereas the transfers to hospitals were less common (p < 0.001). Discussion : Residents had complex clinical situation and their care pathway were different according to the referrer. From the NH, the HAH was used to provide more often end of life care, and from hospital setting, the residents received more acute care with a higher risk of readmission. Readmission causes should be analyzed.
- Published
- 2022
- Full Text
- View/download PDF
31. Prognostic factors for the occurrence of post-operative shoulder stiffness after arthroscopic rotator cuff repair: a systematic review.
- Author
-
Stojanov T, Modler L, Müller AM, Aghlmandi S, Appenzeller-Herzog C, Loucas R, Loucas M, and Audigé L
- Subjects
- Arthroscopy adverse effects, Humans, Male, Prognosis, Shoulder, Rotator Cuff surgery, Rotator Cuff Injuries diagnosis, Rotator Cuff Injuries epidemiology, Rotator Cuff Injuries surgery
- Abstract
Background: Post-operative shoulder stiffness (POSS) is one of the most frequent complications after arthroscopic rotator cuff repair (ARCR). Factors specifying clinical prediction models for the occurrence of POSS should rely on the literature and expert assessment. Our objective was to map prognostic factors for the occurrence of POSS in patients after an ARCR., Methods: Longitudinal studies of ARCR reporting prognostic factors for the occurrence of POSS with an endpoint of at least 6 months were included. We systematically searched Embase, Medline, and Scopus for articles published between January 1, 2014 and February 12, 2020 and screened cited and citing literature of eligible records and identified reviews. The risk of bias of included studies and the quality of evidence were assessed using the Quality in Prognosis Studies tool and an adapted Grading of Recommendations, Assessment, Development and Evaluations framework. A database was implemented to report the results of individual studies. The review was registered on PROSPERO (CRD42020199257)., Results: Seven cohort studies including 23 257 patients were included after screening 5013 records. POSS prevalence ranged from 0.51 to 8.75% with an endpoint ranging from 6 to 24 months. Due to scarcity of data, no meta-analysis could be performed. Overall risk of bias and quality of evidence was deemed high and low or very low, respectively. Twenty-two potential prognostic factors were identified. Increased age and male sex emerged as protective factors against POSS. Additional factors were reported but do require further analyses to determine their prognostic value., Discussion: Available evidence pointed to male sex and increased age as probable protective factors against POSS after ARCR. To establish a reliable pre-specified set of factors for clinical prediction models, our review results require complementation with an expert's opinion., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
32. Prediction of Shoulder Stiffness After Arthroscopic Rotator Cuff Repair.
- Author
-
Audigé L, Aghlmandi S, Grobet C, Stojanov T, Müller AM, Felsch Q, Gleich J, Flury M, and Scheibel M
- Subjects
- Arthroscopy, Case-Control Studies, Female, Humans, Retrospective Studies, Shoulder, Treatment Outcome, Rotator Cuff surgery, Rotator Cuff Injuries surgery
- Abstract
Background: Postoperative shoulder stiffness (POSS) is a prevalent adverse event after arthroscopic rotator cuff repair (ARCR) that is associated with major limitations in everyday activities and prolonged rehabilitation., Purpose/hypothesis: The purpose was to develop a predictive model for determining the risk of POSS within 6 months after primary ARCR. We hypothesized that sufficient discrimination ability of such a model could be achieved using a local institutional database., Study Design: Case-control study; Level of evidence, 3., Methods: Consecutive primary ARCRs documented in a local clinical registry between 2013 and 2017 were included, and patients who experienced POSS before the final clinical 6-month follow-up were identified. A total of 29 prognostic factor candidates were considered, including patient-related factors (n = 7), disease-related factors (n = 9), rotator cuff integrity factors (n = 6), and operative details (n = 7). We used imputed data for the primary analysis, and a sensitivity analysis was conducted using complete case data. Logistic regression was applied to develop a model based on clinical relevance and statistical criteria. To avoid overfitting in the multivariable model, highly correlated predictors were not included together in any model. A final prognostic model with a maximum of 8 prognostic factors was considered. The model's predictive accuracy was assessed by the area under the receiver operating characteristic curve (AUC). Internal validation was performed using bootstrapping., Results: Of 1330 ARCR cases (N = 1330 patients), 112 (8.4%) patients had POSS. Our final model had a moderate predictive ability with an AUC of 0.67. The predicted risks of POSS ranged from 2.3% to 38.9% and were significantly higher in women; patients with partial tears, low baseline passive shoulder abduction, and lack of tendon degeneration; and when no acromioplasty was performed., Conclusion: A prognostic model for POSS was developed for patients with ARCR, offering a personalized risk evaluation to support the future decision process for surgery and rehabilitation.
- Published
- 2021
- Full Text
- View/download PDF
33. Swiss-wide multicentre evaluation and prediction of core outcomes in arthroscopic rotator cuff repair: protocol for the ARCR_Pred cohort study.
- Author
-
Audigé L, Bucher HCC, Aghlmandi S, Stojanov T, Schwappach D, Hunziker S, Candrian C, Cunningham G, Durchholz H, Eid K, Flury M, Jost B, Lädermann A, Moor BK, Moroder P, Rosso C, Schär M, Scheibel M, Spormann C, Suter T, Wieser K, Zumstein M, and Müller AM
- Subjects
- Arthroscopy, Cohort Studies, Humans, Multicenter Studies as Topic, Quality of Life, Switzerland, Treatment Outcome, Rotator Cuff diagnostic imaging, Rotator Cuff surgery, Rotator Cuff Injuries surgery
- Abstract
Introduction: In the field of arthroscopic rotator cuff repair (ARCR), reporting standards of published studies differ dramatically, notably concerning adverse events (AEs). In addition, prognostic studies are overall methodologically poor, based on small data sets and explore only limited numbers of influencing factors. We aim to develop prognostic models for individual ARCR patients, primarily for the patient-reported assessment of shoulder function (Oxford Shoulder Score (OSS)) and the occurrence of shoulder stiffness 6 months after surgery. We also aim to evaluate the use of a consensus core event set (CES) for AEs and validate a severity classification for these events, considering the patient's perspective., Methods and Analysis: A cohort of 970 primary ARCR patients will be prospectively documented from several Swiss and German orthopaedic clinics up to 24 months postoperatively. Patient clinical examinations at 6 and 12 months will include shoulder range of motion and strength (Constant Score). Tendon repair integrity status will be assessed by ultrasound at 12 months. Patient-reported questionnaires at 6, 12 and 24 months will determine functional scores (subjective shoulder value, OSS), anxiety and depression scores, working status, sports activities, and quality of life (European Quality of Life 5 Dimensions 5 Level questionnaire). AEs will be documented according to a CES. Prognostic models will be developed using an internationally supported regression methodology. Multiple prognostic factors, including patient baseline demographics, psychological, socioeconomic and clinical factors, rotator cuff integrity, concomitant local findings, and (post)operative management factors, will be investigated., Ethics and Dissemination: This project contributes to the development of personalised risk predictions for supporting the surgical decision process in ARCR. The consensus CES may become an international reference for the reporting of complications in clinical studies and registries. Ethical approval was obtained on 1 April 2020 from the lead ethics committee (EKNZ, Basel, Switzerland; ID: 2019-02076). All participants will provide informed written consent before enrolment in the study., Trial Registration Number: NCT04321005., Protocol Version: Version 2 (13 December 2019)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)
- Published
- 2021
- Full Text
- View/download PDF
34. Embryo vitrification using a novel semi-automated closed system yields in vitro outcomes equivalent to the manual Cryotop method.
- Author
-
Roy TK, Brandi S, Tappe NM, Bradley CK, Vom E, Henderson C, Lewis C, Battista K, Hobbs B, Hobbs S, Syer J, Lanyon SR, Dopheide SM, Peura TT, McArthur SJ, Bowman MC, and Stojanov T
- Subjects
- Animals, Female, Humans, Mice, Pregnancy, Cryopreservation methods, Embryo Transfer methods, Fertilization in Vitro methods, Vitrification
- Abstract
Study Question: Can the equilibration steps prior to embryo vitrification be automated?, Summary Answer: We have developed the 'Gavi' system which automatically performs equilibration steps before closed system vitrification on up to four embryos at a time and gives in vitro outcomes equivalent to the manual Cryotop method., What Is Known Already: Embryo cryopreservation is an essential component of a successful assisted reproduction clinic, with vitrification providing excellent embryo survival and pregnancy outcomes. However, vitrification is a manual, labour-intensive and highly skilled procedure, and results can vary between embryologists and clinics. A closed system whereby the embryo does not come in direct contact with liquid nitrogen is preferred by many clinics and is a regulatory requirement in some countries., Study Design, Size, Duration: The Gavi system, an automation instrument with a novel closed system device, was used to equilibrate embryos prior to vitrification. Outcomes for embryos automatically processed with the Gavi system were compared with those processed with the manual Cryotop method and with fresh (non-vitrified) controls., Participants/materials, Setting, Methods: The efficacy of the Gavi system (Alpha model) was assessed for mouse (Quackenbush Swiss and F1 C57BL/6J x CBA) zygotes, cleavage stage embryos and blastocysts, and for donated human vitrified-warmed blastocysts. The main outcomes assessed included recovery, survival and in vitro embryo development after vitrification-warming. Cooling and warming rates were measured using a thermocouple probe., Main Results and the Role of Chance: Mouse embryos vitrified after processing with the automated Gavi system achieved equivalent in vitro outcomes to that of Cryotop controls. For example, for mouse blastocysts both the Gavi system (n = 176) and manual Cryotop method (n = 172) gave a 99% recovery rate, of which 54 and 50%, respectively, progressed to fully hatched blastocysts 48 h after warming. The outcomes for human blastocysts processed with the Gavi system (n = 23) were also equivalent to Cryotop controls (n = 13) including 100% recovery for both groups, of which 17 and 15%, respectively, progressed to fully hatched blastocysts 48 h after warming. The cooling and warming rates achieved with the Gavi system were 14 136°C/min and 11 239°C/min, respectively., Limitations, Reasons for Caution: Testing of the Gavi system described here was limited to in vitro development of embryos from two mouse strains and a limited number of human embryos. Validation of Gavi system advanced production models is now required to confirm the success of semi-automated vitrification, including clinical evaluation of pregnancy outcomes from the transfer of Gavi vitrified-warmed human embryos., Wider Implications of the Findings: The Gavi system has the potential to revolutionize and standardize vitrification of embryos and oocytes. The success of the Gavi system shows that it is possible to semi-automate complicated labour-intensive ART methods and processes, and opens up the possibility for further improvements in clinical outcomes and efficiencies in the ART clinic., Study Funding/competing Interests: This study was funded by Genea Ltd. S.B., N.M.T., T.T.P., S.J.M., M.C.B. and T.S. are shareholders of Genea Ltd. E.V., C.H., C.L., S.R.L. and S.M.D. are shareholders of Planet Innovation Pty Ltd. The remaining authors are employees of either Genea Ltd. or Planet Innovation Pty Ltd., (© The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2014
- Full Text
- View/download PDF
35. Cell lines from morphologically abnormal discarded IVF embryos are typically euploid and unaccompanied by intrachromosomal aberrations.
- Author
-
Bradley CK, Peura T, Dumevska B, Jovasevic A, Chami O, Schmidt U, Jansen RP, and Stojanov T
- Subjects
- Cell Line, DNA Copy Number Variations, Embryonic Stem Cells, Female, Fertilization in Vitro, Humans, Karyotyping, Pluripotent Stem Cells, Blastocyst cytology, Polyploidy
- Abstract
Routine IVF practices result in the discarding of a significant proportion of embryos due to their unsuitability for transfer or cryopreservation. The present study plated clinically unusable human blastocysts to derive cellular outgrowths for aneuploidy studies and genome-wide analysis of DNA copy number variations, and to evaluate their potential as a source for pluripotent stem cells. Just 79 cellular outgrowths were obtained from 1026 abnormal blastocysts (7.7%), reflecting their low developmental potential. Of these, 13 (16.5%) were karyotypically abnormal and included trisomies frequently detected in miscarriages, each of which was uniform (nonmosaic) and the result of meiotic nondisjunction. Evaluation of submicroscopic DNA gains and losses in 10 diploid cellular outgrowths did not identify increased rates of copy number variations. Five of these outgrowths were shown to express pluripotency markers and could be developed into cell lineages representative of the three germ layers. These data suggest that embryos with chromosomal abnormalities resist cell-line derivation, and mosaic aneuploidy produced from mitotic nondisjunction, common in preimplantation embryos, is likely to be diminished or lost under conditions of diploid cell competition. Furthermore, this work demonstrated that abnormal embryos discarded in IVF programmes can provide a valuable source for pluripotent stem cell lines. During IVF, a large proportion of embryos are clinically unsuitable due to abnormal development and these embryos only have a small chance of achieving a pregnancy. Here we used these abnormal embryos to create cell lines for genetic testing and to determine their potential as stem cells. Of the 1026 abnormal embryos used, 79 (7.7%) created cell lines, reflecting their low developmental potential. Of those, only 16.5% had chromosomal anomalies, a much lower number than expected. This included chromosome abnormalities frequently observed in miscarriages, all of which were found in each cell tested (nonmosaic) and originated from the egg or the sperm as opposed to cell division. In-depth testing of 10 normal cell lines for small DNA gains and losses did not reveal an increased frequency of mutations. Furthermore, five of the cell lines were examined for stem cell properties and found to exhibit the hallmark features of stem cells including their ability to make mature cells from different parts of the body. Our data suggest that embryos with abnormal chromosomes resist making cell lines and that abnormalities that arise during cell division are likely to be lost due to competition with normal cells. We also demonstrated that abnormal embryos usually discarded in IVF programmes can provide a valuable source for stem cell lines., (Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
36. Derivation of Huntington's disease-affected human embryonic stem cell lines.
- Author
-
Bradley CK, Scott HA, Chami O, Peura TT, Dumevska B, Schmidt U, and Stojanov T
- Subjects
- Animals, Antigens, Surface metabolism, Cell Differentiation, Cell Shape, Embryonic Stem Cells transplantation, Humans, Huntingtin Protein, Huntington Disease genetics, Karyotyping, Mice, Mice, SCID, Microtubule-Associated Proteins metabolism, Mutagenesis, Insertional, Neurons cytology, Neurons metabolism, Octamer Transcription Factor-3 metabolism, Polymorphism, Genetic, Proteoglycans metabolism, Stage-Specific Embryonic Antigens metabolism, Teratoma pathology, Trinucleotide Repeat Expansion, Embryonic Stem Cells metabolism, Huntington Disease pathology, Nerve Tissue Proteins genetics, Nuclear Proteins genetics
- Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by an expansion of cytosine-adenine-guanine (CAG) repeats in the Huntingtin gene Htt. To facilitate research into HD, we have derived 4 human embryonic stem cell (hESC) lines containing ≥ 40 CAG repeats in exon 1 of Htt: SIVF017-HD (CAG₄₀), SIVF018-HD (CAG₄₆), SIVF020-HD (CAG₄₈), and SIVF046-HD (CAG₄₅). Additionally, we have derived a normal sibling-matched control for SIVF020-HD, cell line SIVF019. All 5 hESC lines had a normal karyotype, expressed pluripotency markers including Oct4, SSEA3, and Tra-1-81, and could be maintained in culture for multiple (>40) passages. Teratoma studies revealed that the hESC lines were capable of differentiating into cells representative of the 3 germ layers. Furthermore, in vitro neuronal differentiation experiments have confirmed that the hESC lines were able to generate MAP2-positive neuronal cells that express the Htt protein. Combined, these experiments confirm that the cell lines represent pluripotent stem cell lines. These HD-affected hESC lines will be made available to biomedical research laboratories and will provide a valuable tool to investigate the mechanisms and potential treatments for HD.
- Published
- 2011
- Full Text
- View/download PDF
37. Generation of human embryonic stem cells.
- Author
-
Peura T, Schaft J, Dumevska B, and Stojanov T
- Subjects
- Blastocyst Inner Cell Mass cytology, Embryo Culture Techniques, Embryo, Mammalian cytology, Humans, Cell Culture Techniques, Cell Line, Embryonic Stem Cells cytology
- Abstract
This unit describes generation of human embryonic stem cell lines from early human embryos. The focus is on actual handling of embryos and early embryonic outgrowths, omitting steps required for actual generation, freezing, and thawing of embryos, as well as further culture and characterization of newly derived stem cells. Hence, the initial culture of embryos to a blastocyst stage is described, followed by removal of the protective zona pellucida layer, isolation of the inner cell mass (ICM), subsequent plating of ICM or whole embryo and, finally, the first few passages of an early embryonic outgrowth. A few alternative procedures for some steps such as zona removal and inner cell mass isolation are described, to allow procedures to be modified according to circumstances.
- Published
- 2011
- Full Text
- View/download PDF
38. Derivation of three new human embryonic stem cell lines.
- Author
-
Bradley CK, Chami O, Peura TT, Bosman A, Dumevska B, Schmidt U, and Stojanov T
- Subjects
- Animals, Australia, Cytogenetic Analysis, DNA metabolism, Embryonic Stem Cells metabolism, Fertilization in Vitro, Gene Expression Regulation, Developmental, Humans, Mice, Pluripotent Stem Cells cytology, Teratoma pathology, Cell Line cytology, Embryonic Stem Cells cytology
- Abstract
Human embryonic stem cells are pluripotent cells capable of extensive self-renewal and differentiation to all cells of the embryo proper. Here, we describe the derivation and characterization of three Sydney IVF human embryonic stem cell lines not already reported elsewhere, designated SIVF001, SIVF002, and SIVF014. The cell lines display typical compact colony morphology of embryonic stem cells, have stable growth rates over more than 40 passages and are cytogenetically normal. Furthermore, the cell lines express pluripotency markers including Nanog, Oct4, SSEA3 and Tra-1-81, and are capable of generating teratoma cells derived from each of the three germ layers in immunodeficient mice. These experiments show that the cell lines constitute pluripotent stem cell lines.
- Published
- 2010
- Full Text
- View/download PDF
39. Derivation of human embryonic stem cell lines from vitrified human embryos.
- Author
-
Peura TT, Schaft J, and Stojanov T
- Subjects
- Cell Line, Coculture Techniques methods, Embryo Culture Techniques methods, Humans, Cell Culture Techniques methods, Cryopreservation methods, Embryonic Stem Cells cytology
- Abstract
Human embryonic stem cell lines are usually derived from human embryos that have become excess to clinical needs in assisted reproduction programs, whether because the couple in question has completed their family or because the embryo was found to be clinically unsuitable for transfer due to severe genetic condition (in case of pre-implantation genetic diagnosis, PGD). Culturing embryos to a blastocyst stage (5-6 days after IVF) before embryo transfer or cryopreservation instead of earlier commonly used 8-cell stage (3 days after IVF) calls for new methods for embryo cryopreservation and allows higher efficiencies for the actual stem cell derivation. Despite the vast advances in other fields of embryonic stem cell research, methods for derivation of new lines have not changed much over the years, mainly due to scarcity of embryos limiting experimentation. We describe here methods required to derive new embryonic stem cell lines starting from the initial cryopreservation of an embryo and finishing with a new cell line. We cover embryo cryopreservation and warming using a highly efficient vitrification method, the production of feeder cells and feeder plates, as well as embryo handling, plating and critical early passages, including earliest possible cryopreservation of putative stem cells using vitrification.
- Published
- 2010
- Full Text
- View/download PDF
40. Improved membrane proteomics coverage of human embryonic stem cells by peptide IPG-IEF.
- Author
-
McQuade LR, Schmidt U, Pascovici D, Stojanov T, and Baker MS
- Subjects
- Algorithms, Biomarkers, Cells, Cultured, Chromatography, Liquid, Embryonic Stem Cells cytology, Humans, Isoelectric Focusing, Methods, Peptides analysis, Tandem Mass Spectrometry, Embryonic Stem Cells chemistry, Membrane Proteins analysis, Proteomics methods
- Abstract
Protein biomarkers are fundamental tools for the characterization of stem cells and for tracking their differentiation and maturation down developmental lineages. Technology development allowing increased coverage of difficult cellular proteomes should allow for the discovery of new and novel membrane protein biomarkers for use by the stem cell research community. The amphipathic and highly hydrophobic nature and relative low abundance of many membrane proteins present significant analytical challenges. These difficulties are amplified when the source material (tissue or cells) is only available in limited quantities (e.g., embryonic stem cells). Recent advances in enrichment for purer membrane fractions, the enzymatic and chemical digestion of membrane proteins in the presence of solvents or chaotropes, and the use of "shotgun" proteomics methodologies have gradually resulted in increased membrane proteome coverage with numbers of predicted integral membrane proteins now in excess of 1000 being routinely reported. We have recently demonstrated the advantages of using peptide isoelectric focusing in the first dimension on immobilized pH gradients (peptide IPG-IEF) followed by reversed phase chromatography and tandem MS to increase membrane proteome coverage. This study looked at achieving a similar level of membrane proteome coverage using modifications to reported methodologies while restricting the number of characterized human embryonic stem cells to 10(7) cells. Two-thousand two-hundred and ninety-two (2292) nonredundant proteins were identified with two or more high accuracy peptide matches from 260 mug of a human embryonic stem cell membrane enriched fraction with a false discovery rate of 0.32%. Gene Ontology (GO) mapping predicted 1279 (44.9%) of this list to be membrane proteins of which 395 proteins were predicted to be derived from the plasma membrane compartment. The TMHMM algorithm predicted 904 integral membrane proteins with up to 16 transmembrane helices. Collectively, we assert that the substantial membrane proteome coverage achieved using these procedures will enable rapid advances in the identification and quantitation of novel membrane proteins as markers of differentiation status and/or genetic mutation from relatively low numbers of cultured embryonic stem cells.
- Published
- 2009
- Full Text
- View/download PDF
41. Karyotypically normal and abnormal human embryonic stem cell lines derived from PGD-analyzed embryos.
- Author
-
Peura T, Bosman A, Chami O, Jansen RP, Texlova K, and Stojanov T
- Subjects
- Animals, Biopsy, Fine-Needle, Blastocyst physiology, Cell Culture Techniques, Embryonic Stem Cells cytology, Embryonic Stem Cells transplantation, Female, Gene Expression physiology, Humans, Karyotyping, Male, Mice, Mice, SCID, Preimplantation Diagnosis, Teratoma, Aneuploidy, Cell Line, Embryonic Stem Cells physiology
- Abstract
Although a normal karyotype is generally a requirement for stem cell lines, new applications are likely to emerge for stem cells with defined chromosomal aneuploidies. We therefore investigated the use of embryos found to be aneuploid on biopsy followed by preimplantation genetic diagnosis (PGD) with fluorescent in situ hybridization (FISH), and developmentally arrested embryos for stem cell derivation. Eleven stem cell lines were obtained from 41 embryos in 36 cultures, with higher success rate achieved from PGD-analyzed, developmentally advanced embryos (45%) than from clinically unsuitable non-PGD embryos (13%). The resulting stem cell lines were karyotyped, and surprisingly, six of the nine lines from aneuploid embryos as well as both lines from non-PGD embryos were karyotypically normal. Three lines from PGD embryos were aneuploid exhibiting trisomy 5, trisomy 16, and an isochromosome 13, respectively. None of the aneuploid lines presented the same anomally as the original PGD analysis. Our study has three important implications. First, we confirm the ability to produce stem cell lines from PGD-tested embryos as well as developmentally abnormal embryos, offering specialty stem cell lines for research into the clinically important aneuploidies. Second, we observe that stem cell derivation from apparently aneuploid embryos is often thwarted by underlying mosaicism and emerging dominance of the stem cell line by karyotypically normal cells. The corollary, however, is that regular production of normal stem cell lines from developmentally abnormal embryos ordinarity discarded opens a new source of embryos for stem cells, whether for research or for eventual therapeutic use within the donating families.
- Published
- 2008
- Full Text
- View/download PDF
42. Derivation of human embryonic stem cell lines.
- Author
-
Peura TT, Bosman A, and Stojanov T
- Subjects
- Animals, Cell Culture Techniques, Cryopreservation, Culture Media, Humans, Oxygen metabolism, Embryonic Stem Cells cytology, Embryonic Stem Cells physiology, Research Embryo Creation
- Abstract
Human embryonic stem cells (hESC) are undifferentiated cells derived from an early embryo that can grow in vitro indefinitely, while retaining their capability to differentiate into specialized somatic cell types. Over the last decade there has been great interest in derivation and culture of these cells, as they can potentially provide a supply of readily available differentiated cells and tissues of all types to be used for therapeutic purposes in cell transplantation in humans, as well as for other medical uses such as drug discovery. The source of hESC lines is usually excess human embryos from in vitro fertilization treatments, although novel ways of producing hESCs have been suggested recently. The actual methods of hESC derivation have not changed greatly since the first report by Thomson et al. in 1998 . However, the main emphasis over the last several years has been in finding defined conditions for derivation and culture of hESCs, because to enable the clinical use of hESC for cell transplantation, the use of animal derived biological components is no longer acceptable. For basic research, the aim is to replace even human derived materials with completely defined systems. In this paper we describe methods utilized in our laboratory for hESC derivation and describe two studies conducted in an attempt to improve derivation efficiency and to enable research outcomes to be achieved using fewer embryos.
- Published
- 2007
- Full Text
- View/download PDF
43. Flow cytometric sorting of non-human primate sperm nuclei.
- Author
-
O'Brien JK, Stojanov T, Heffernan SJ, Hollinshead FK, Vogelnest L, Maxwell WM, and Evans G
- Subjects
- Animals, Benzimidazoles, Callithrix, Cell Separation methods, DNA analysis, Flow Cytometry methods, Fluorescent Dyes, Humans, In Situ Hybridization, Fluorescence veterinary, Male, Pan troglodytes, Papio hamadryas, X Chromosome, Y Chromosome, Cell Nucleus chemistry, Cell Separation veterinary, Flow Cytometry veterinary, Primates, Sex Determination Analysis veterinary, Spermatozoa ultrastructure
- Abstract
Pre-determination of the sex of offspring has implications for management and conservation of captive wildlife species, particularly those with single sex-dominated social structures. Our goal is to adapt flow cytometry technology to sort spermatozoa of non-human primate species for use with assisted reproductive technologies. The objectives of this study were to: (i) determine the difference in DNA content between X- and Y-bearing spermatozoa (ii) sort sperm nuclei into X- and Y-enriched samples; and (iii) assess the accuracy of sorting. Spermatozoa were collected from two common marmosets (Callithrix jacchus), seven hamadryas baboons (Papio hamadryas) and two common chimpanzees (Pan troglodytes). Human spermatozoa from one male were used as a control. Sperm nuclei were stained (Hoechst 33342), incubated and analyzed using a high-speed cell sorter. Flow cytometric reanalysis of sorted samples (sort reanalysis, 10,000 events/sample) and fluorescence in situ hybridization (FISH; 500 sperm nuclei/sample) were used to evaluate accuracy of sorting. Based on fluorescence intensity of X- and Y-bearing sperm nuclei, the difference in DNA content between X and Y populations was 4.09 +/- 0.03, 4.20 +/- 0.03, 3.30 +/- 0.01, and 2.97 +/- 0.05%, for marmoset, baboon, chimpanzee and human, respectively. Sort reanalysis and FISH results were similar; combined data revealed high levels of purity for X- and Y-enriched samples (94 +/- 0.9 and 93 +/- 0.8%, 94 +/- 0.7 and 94 +/- 0.5%, 91 +/- 0.9 and 97 +/- 0.6%, 94 +/- 0.6 and 94 +/- 0.9%, for marmoset, baboon, chimpanzee and human, respectively). These data indicate the potential for high-purity sorting of spermatozoa from non-human primates.
- Published
- 2005
- Full Text
- View/download PDF
44. Evidence for the autocrine induction of capacitation of mammalian spermatozoa.
- Author
-
Wu C, Stojanov T, Chami O, Ishii S, Shimizu T, Li A, and O'Neill C
- Subjects
- 1-Alkyl-2-acetylglycerophosphocholine Esterase, Animals, Base Sequence, Culture Media, DNA Primers, Fertilization physiology, In Vitro Techniques, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Phospholipases A metabolism, Platelet Activating Factor pharmacology, Platelet Activating Factor physiology, Platelet Membrane Glycoproteins genetics, Semen enzymology, Spermatozoa drug effects, Spermatozoa physiology, Receptors, Cell Surface, Receptors, G-Protein-Coupled, Sperm Capacitation
- Abstract
Mammalian spermatozoa require a maturational event after ejaculation that allows them to acquire the capacity for fertilization. This process, known as capacitation, occurs spontaneously in simple defined medium implicating a potential role of autocrine induction. This study shows that the ether phospholipid 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphocholine (PAF) meets the criteria for an autocrine mediator of capacitation. Sperm released PAF after their dilution into capacitation medium and expressed a receptor for PAF on their membranes. PAF stimulated changes in the motility of sperm and enhanced fertilization in vitro. These actions were inhibited by a PAF receptor antagonist (UR-12519) and by extracellular recombinant PAF:acetylhydrolase (an enzyme that degrades PAF to a biologically inert form). Seminal plasma contained an acid-labile PAF:acetylhydrolase, whereas capacitation was inhibited by an acid-labile factor within seminal plasma, implicating this factor as a potential decapacitation factor within seminal plasma. Sperm from a PAF receptor knock-out mouse strain failed to express the receptor and displayed a significantly (p < 0.01) reduced rate of capacitation, as assessed by the spontaneous onset of the acrosome reaction in vitro. When used for in vitro fertilization, sperm from PAF receptor knock-out mice gave a significantly lower rate of fertilization (21.5%) than did wild-type sperm (66.7%). The study shows for the first time the operation of an autocrine loop that induces capacitation in sperm in vitro and shows that this loop acts in concert with other mediators of capacitation to promote efficient fertilization.
- Published
- 2001
- Full Text
- View/download PDF
45. Characterization and functional significance of calcium transients in the 2-cell mouse embryo induced by an autocrine growth factor.
- Author
-
Emerson M, Travis AR, Bathgate R, Stojanov T, Cook DI, Harding E, Lu DP, and O'Neill C
- Subjects
- Animals, Autocrine Communication, Estrenes pharmacology, Inositol 1,4,5-Trisphosphate antagonists & inhibitors, Inositol 1,4,5-Trisphosphate metabolism, Macrocyclic Compounds, Mice, Oxazoles pharmacology, Phosphodiesterase Inhibitors pharmacology, Pyrrolidinones pharmacology, Blastocyst metabolism, Calcium metabolism, Platelet Activating Factor metabolism
- Abstract
Growth of preimplantation embryos is influenced by autocrine trophic factors that need to act by the 2-cell stage, but their mode of action is not yet described. This report shows that late zygote and 2-cell stage mouse embryos responded to embryo-derived platelet-activating factor (PAF) with transient increases in intracellular calcium concentration ([Ca(2+)](i)). [Ca(2+)](i) transients were single global events and were specifically induced by embryo-derived PAF. They were blocked by inhibition of phospholipase C (U 73122) and an inositol trisphosphate (IP(3)) receptor antagonist (xestospongin C), indicating the release of calcium from IP(3)-sensitive intracellular stores. Transients were also inhibited by the absence of calcium from extracellular medium and partially inhibited by treatment with dihydropyridine (nifedipine, 10 micrometer), but not pimozide (an inhibitor of an embryonic T-type calcium channel). (+/-)BAY K8644 (an L-type channel agonist) induced [Ca(2+)](i) transients, yet these were completely inhibited by nifedipine (10 micrometer). The complete inhibition of BAY K8644, but only partial inhibition of PAF by nifedipine shows that L-type channels were only partly responsible for the calcium influx. Depolarization of 2-cell embryos by 50 mm K(+) did not inhibit PAF-induced calcium transients, showing that the influx channels were not voltage-dependent. Depletion of intracellular calcium stores by thapsigargin revealed the presence of store-operated channels. The interdependent requirement for IP(3)-sensitive internal calcium stores and extracellular calcium in the generation of PAF-induced transients may be explained by a requirement for capacitative calcium entry via store-operated channels. A functionally important role for the PAF-induced transients is supported by the observation that inhibition of [Ca(2+)](i) transients by a PAF-antagonist (WEB 2086) or an intracellular calcium chelator (1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis-acetoxymethyl ester; BAPTA-AM) caused marked inhibition of early embryo development. Growth inhibition by BAPTA-AM was relieved by addition of exogenous PAF.
- Published
- 2000
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.