Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 297
Filtrar
Mais filtros

Coleção BVS Equador
Tipo de documento
Intervalo de ano de publicação
1.
J Assist Reprod Genet ; 39(2): 505-516, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35032286

RESUMO

PURPOSE: As a further step to elucidate the actual diverse spectrum of oncofertility practices for breast cancer around the globe, we present and discuss the comparisons of oncofertility practices for breast cancer in limited versus optimum resource settings based on data collected in the Repro-Can-OPEN Study Part I & II. METHODS: We surveyed 39 oncofertility centers including 14 in limited resource settings from Africa, Asia & Latin America (Repro-Can-OPEN Study Part I), and 25 in optimum resource settings from the United States, Europe, Australia and Japan (Repro-Can-OPEN Study Part II). Survey questions covered the availability of fertility preservation and restoration options offered to young female patients with breast cancer as well as the degree of utilization. RESULTS: In the Repro-Can-OPEN Study Part I & II, responses for breast cancer and calculated oncofertility scores showed the following characteristics: (1) higher oncofertility scores in optimum resource settings than in limited resource settings especially for established options, (2) frequent utilization of egg freezing, embryo freezing, ovarian tissue freezing, GnRH analogs, and fractionation of chemo- and radiotherapy, (3) promising utilization of oocyte in vitro maturation (IVM), (4) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, and stem cells reproductive technology as they are still in preclinical or early clinical research settings, (5) recognition that technical and ethical concerns should be considered when offering advanced and innovative oncofertility options. CONCLUSIONS: We presented a plausible oncofertility best practice model to guide oncofertility teams in optimizing care for breast cancer patients in various resource settings.


Assuntos
Neoplasias da Mama , Preservação da Fertilidade , Neoplasias , Neoplasias da Mama/complicações , Embrião de Mamíferos , Feminino , Humanos , Técnicas de Maturação in Vitro de Oócitos , Inquéritos e Questionários
2.
Hum Reprod ; 34(12): 2456-2466, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31825483

RESUMO

STUDY QUESTION: Are uterine natural killer (uNK) cell numbers and their distribution relative to endometrial arterioles altered in women with recurrent implantation failure (RIF) compared to women with embryo implantation success (IS)? SUMMARY ANSWER: uNK cell numbers and their distribution relative to endometrial arterioles are not significantly different in women with RIF compared to women in whom embryo implantation occurs successfully following IVF. WHAT IS ALREADY KNOWN: uNK cells are regulators of decidual angiogenesis and spiral arteriole remodelling during early pregnancy. Although some studies have shown that uNK cell numbers may be altered in women with RIF, the methods used to measure uNK cell numbers have proven inconsistent, making reproduction of these results difficult. It is unclear, therefore, whether the results reported so far are reproducible. Moreover, it is not known how uNK cell numbers may impact IVF outcomes. Despite the lack of conclusive evidence, uNK cell numbers are often evaluated as a prognostic criterion in women undergoing assisted reproductive procedures. STUDY DESIGN, SIZE, DURATION: Endometrial pipelle biopsies were collected 6-8 days post-LH surge in natural cycles from women with RIF (n = 14), women with IS (n = 11) and women with potential RIF at the time of the study (PRIF; n = 9) from 2013 to 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS: uNK cells (i.e. CD56+ and/or CD16+ phenotypes) and their distribution relative to endometrial arterioles were investigated by standard immunohistochemistry protocols and quantified using Aperio ScanScopeXT images digitized by ImageJ and deconvoluted into binary images for single cell quantification using a Gaussian Blur and Yen algorithm. MAIN RESULTS AND THE ROLE OF CHANCE: There was no significant difference in the cell density of CD56+ or CD16+ uNK cells in women with RIF compared to women with IS or PRIF. There was a higher proportion of uNK cells in the distal regions compared to the regions closest to the arterioles in all patient groups. Further, we identified a significant reduction in uNK cell density in women who had a previous pregnancy compared to those who had not, regardless of their current implantation status. LARGE SCALE DATA: Not applicable. LIMITATIONS, REASONS FOR CAUTION: Spiral arterioles could not always be accurately identified by digital image analysis; therefore, all endometrial arterioles were selected and analysed. Patient numbers for the study were low. However, as the clinical phenotypes of each patient were well defined, and endometrial dating was accurately determined by three independent pathologists, differences between patient groups with respect to the uNK numbers and distribution should have been measurable if uNK cell counts were to be useful as a prognostic marker of RIF. WIDER IMPLICATIONS OF THE FINDINGS: Our findings demonstrate that CD56+ and CD16+ uNK cell numbers are not significantly different in women with RIF in a typical cohort of women undergoing IVF. Further, prior pregnancy was associated with a significantly reduced number of uNK cells in both the RIF and IS patient groups, suggestive of a long-term pregnancy induced suppression of uNK cells. Combined, these findings do not support the clinical value of using uNK cell numbers as a prognostic indicator of implantation success with IVF treatment. STUDY FUNDING/COMPETING INTEREST(S): Funding for this work was provided by Royal Women's Hospital Foundation. P.P. was supported by an NHMRC Early Career Fellowship [TF 11/14] and W.T.T. was supported by an NHMRC Postgraduate Scholarship [1055814]. The authors do not have any competing interests with this study.


Assuntos
Implantação do Embrião/imunologia , Endométrio/imunologia , Infertilidade Feminina/imunologia , Células Matadoras Naturais , Adulto , Arteríolas/imunologia , Endométrio/irrigação sanguínea , Feminino , Humanos , Gravidez
3.
Hum Reprod ; 32(12): 2423-2430, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29045667

RESUMO

STUDY QUESTION: What are the reproductive experiences and outcomes of people who store reproductive material before cancer treatment? SUMMARY ANSWER: Of respondents who had tried to achieve pregnancy since completing cancer treatment almost all had succeeded, in most cases through natural conception. WHAT IS KNOWN ALREADY: People of reproductive age who are diagnosed with cancer can cryopreserve reproductive material to guard against the adverse effects on fertility of gonadotoxic treatment. Little is known about the reproductive outcomes of people who undergo fertility preservation before cancer treatment. STUDY DESIGN, SIZE, DURATION: Cross-sectional survey. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women and men who had stored reproductive material before cancer treatment at two private and one public fertility clinics up to June 2014 and were at least 18 years old at the time were identified from medical records and invited to complete an anonymous questionnaire about their reproductive experiences. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 870 potential respondents 302 (171 female and 131 male) returned completed questionnaires yielding a response rate of 34.5% (39.5% and 29.7% for female and male respondents, respectively). Current age was similar for women and men (37.2 years) but men had been diagnosed with cancer significantly earlier in life than women (28.2 versus 30.3 years, P = 0.03). Almost two-thirds of respondents wished to have a child or another child in the future, some of whom knew that they were unable to. One in ten respondents was a parent before the cancer diagnosis and around one-third had had a child since diagnosis or was pregnant (or a partner in pregnancy) at the time of the survey. Of those who had tried to conceive since completing cancer treatment (N = 119) 84% (79% of women and 90% of men) had had a child or were pregnant (or a partner in pregnancy). Most of the pregnancies since the diagnosis of cancer occurred after natural conception (58/100, 58%). Of the 22 women (13% of all women) and 35 men (27% of all men) who had used their stored reproductive material four women (18%) and 28 men (80%) had had a child or were pregnant or a partner in pregnancy at the time of completing the survey. The most commonly stated reason for not using the stored material was not being ready to try for a baby. LIMITATIONS, REASON FOR CAUTION: The relatively low response rate, particularly among men, means that participation bias may have influenced the findings. As type of cancer was self-reported and we did not ask questions about respondents' cancer treatments, it is not possible to link reproductive outcomes to type of cancer or cancer treatment. Also, there is no way of comparing the sample with the populations they were drawn from as data on reproductive outcomes of people who store reproductive material before cancer treatment are not collected routinely. This might have led to over- or underestimates of the reproductive experiences and outcomes reported in this paper. WIDER IMPLICATIONS OF THE FINDINGS: The findings add to the limited evidence about the reproductive outcomes of this growing group of people and can be used to inform the advice given to those contemplating fertility preservation in the context of cancer. STUDY FUNDING/COMPETING INTERESTS: The study was funded by the National Health and Medical Research Council (APP1042347). The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.


Assuntos
Preservação da Fertilidade , Infertilidade/prevenção & controle , Neoplasias/terapia , Adulto , Sobreviventes de Câncer , Estudos Transversais , Criopreservação , Feminino , Fertilidade , Humanos , Infertilidade/complicações , Masculino , Neoplasias/complicações , Oócitos/citologia , Gravidez , Resultado da Gravidez , Reprodução , Inquéritos e Questionários , Resultado do Tratamento , Adulto Jovem
4.
Ecotoxicol Environ Saf ; 124: 50-59, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26454754

RESUMO

Intersex as the manifestation of testicular oocytes (TO) in male gonochoristic fishes has been used as an indicator of estrogenic exposure. Here we evaluated largemouth bass (Micropterus salmoides) or smallmouth bass (Micropterus dolomieu) form 19 National Wildlife Refuges (NWRs) in the Northeast U.S. inhabiting waters on or near NWR lands for evidence of estrogenic endocrine disruption. Waterbodies sampled included rivers, lakes, impoundments, ponds, and reservoirs. Here we focus on evidence of endocrine disruption in male bass evidenced by gonad histopathology including intersex or abnormal plasma vitellogenin (Vtg) concentrations. During the fall seasons of 2008-2010, we collected male smallmouth bass (n=118) from 12 sites and largemouth bass (n=173) from 27 sites. Intersex in male smallmouth bass was observed at all sites and ranged from 60% to 100%; in male largemouth bass the range was 0-100%. Estrogenicity, as measured using a bioluminescent yeast reporter, was detected above the probable no effects concentration (0.73ng/L) in ambient water samples from 79% of the NWR sites. Additionally, the presence of androgen receptor and glucocorticoid receptor ligands were noted as measured via novel nuclear receptor translocation assays. Mean plasma Vtg was elevated (>0.2mg/ml) in male smallmouth bass at four sites and in male largemouth bass at one site. This is the first reconnaissance survey of this scope conducted on US National Wildlife Refuges. The baseline data collected here provide a necessary benchmark for future monitoring and justify more comprehensive NWR-specific studies.


Assuntos
Bass , Transtornos do Desenvolvimento Sexual , Doenças dos Peixes , Animais , Bass/sangue , Bass/metabolismo , Linhagem Celular , Transtornos do Desenvolvimento Sexual/sangue , Transtornos do Desenvolvimento Sexual/metabolismo , Transtornos do Desenvolvimento Sexual/patologia , Transtornos do Desenvolvimento Sexual/veterinária , Disruptores Endócrinos , Estrogênios/metabolismo , Doenças dos Peixes/sangue , Doenças dos Peixes/metabolismo , Doenças dos Peixes/patologia , Lagos , Masculino , New England , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Rios , Estações do Ano , Testículo/patologia , Vitelogeninas/sangue , Leveduras/genética , Leveduras/metabolismo
5.
Eur J Cancer Care (Engl) ; 23(4): 502-13, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24417674

RESUMO

Breast cancer and its treatment have complex ramifications for women of reproductive age, including reduced fertility. With the aim of increasing understanding of what it means to women to manage fertility and motherhood in the years after a diagnosis of breast cancer, in-depth qualitative interviews were conducted with 10 women aged 26-45 years, living in Victoria, Australia, who had been diagnosed with breast cancer aged 25-41. Transcripts were analysed thematically and interpreted within narrative theory. Six themes linking breast cancer to fertility and motherhood were identified: diagnosis as a pivotal life event, robbed of time and choice, significance of fertility, being a mother, narrative justification, and life after breast cancer treatment. Women without children described a preoccupying sorrow about lost fertility. Women's accounts yielded evidence of narrative meaning-making, including justifying their decisions and actions in relation to survival, treatment and fertility, and coping with adversity by developing consoling plots. Breast cancer, fertility and reproductive health are inter-linked in diverse ways which have immediate and long-term consequences. Even if women are receiving optimum fertility management, it is evident that some women of reproductive age will need continuing post-cancer care to manage and ameliorate ramifications of diminished or lost fertility.


Assuntos
Atitude Frente a Saúde , Neoplasias da Mama/psicologia , Fertilidade , Infertilidade Feminina/psicologia , Mães/psicologia , Adaptação Psicológica , Adulto , Antineoplásicos/efeitos adversos , Neoplasias da Mama/terapia , Tomada de Decisões , Feminino , Humanos , Infertilidade Feminina/etiologia , Pessoa de Meia-Idade , Pesquisa Qualitativa , Radioterapia/efeitos adversos , Vitória
6.
Hum Reprod ; 28(11): 2996-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24014608

RESUMO

Ovarian tissue cryopreservation and transplantation is a form of fertility preservation offered to young women at high risk of losing ovarian function after cancer treatment. While there have been successful births resulting from orthotopic site grafts, we report the first case of an ongoing pregnancy from a heterotopic graft in a patient who had previously undergone bilateral oopherectomy for a granulosa cell tumour. Frozen-thawed ovarian tissue was transplanted to the anterior abdominal wall. Subsequent ovarian stimulation and transabdominal ultrasound-guided oocyte retrieval from the grafts resulted in two oocytes. These were fertilized with ICSI and two embryos were transferred. Serial ultrasounds have confirmed an ongoing 26-week intrauterine twin pregnancy. Thus, this first demonstration of a pregnancy from a heterotopic graft site provides unequivocal evidence that cryopreservation preserves complete follicle development and that normal ovarian function can occur at a non-ovarian site. This provides optimism for further efforts to assist women who have had oophorectomy and pelvic surgery or radiotherapy, without an appropriate orthotopic site for grafting.


Assuntos
Preservação da Fertilidade/métodos , Ovariectomia , Ovário/transplante , Parede Abdominal/cirurgia , Adulto , Criopreservação , Transferência Embrionária , Feminino , Humanos , Recuperação de Oócitos , Folículo Ovariano/fisiologia , Indução da Ovulação , Gravidez , Injeções de Esperma Intracitoplásmicas , Transplante Heterotópico
8.
Surg Oncol ; 44: 101817, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36122451

RESUMO

PURPOSE: To quantify joint degeneration and the clinical outcome after curettage and cementation in subchondral giant cell tumors of the bone (GCTB) at the knee. METHODS: We conducted a retrospective analysis of 14 consecutive patients (seven female, seven male) with a mean age of 34 years (range 19-51) who underwent curettage and subchondral cementation for a biopsy-confirmed GCTB at the distal femur or the proximal tibia between August 2001 and August 2017, with a mean follow-up period of 54.6 months (range 16.1-156 months). The Whole-Organ Magnetic Resonance Imaging Score (WORMS), Kellgren-Lawrence (KL) classification, and Musculo-Skeletal Tumor Society (MSTS) score were assessed. RESULTS: Radiological degeneration progressed from preoperative to the latest follow-up, with a median WORMS from 2.0 to 4.0 (p = 0.006); meanwhile, the median KL score remained at 0 (p = 0.102). Progressive degeneration (WORMS) tended to be associated with the proximity of the tumor to the articular cartilage (mean 1.57 mm; range 0-12 mm) (p = 0.085). The most common degenerative findings were cartilage lesions (n = 11), synovitis (n = 5), and osteophytes (n = 4). Mean MSTS score increased from 23.1 (preoperatively) to 28.3 at the latest follow-up (p < 0.01). Seven patients (50%) were treated for a local recurrence, with six revision surgeries performed. Removal of the cement spacer and filling of the cavity with a cancellous autograft was performed in seven patients. Conversion to a total knee arthroplasty was performed in one patient for local tumor control. CONCLUSIONS: Cementation following the curettage of GCTB around the knee is associated with slight degeneration at medium-term follow-up and leads to a significant reduction in pain. Removal of the cement and reconstruction with an autograft may be beneficial in the long term.


Assuntos
Neoplasias Ósseas , Tumor de Células Gigantes do Osso , Neoplasias Ósseas/patologia , Neoplasias Ósseas/cirurgia , Cimentação , Feminino , Tumor de Células Gigantes do Osso/complicações , Tumor de Células Gigantes do Osso/patologia , Tumor de Células Gigantes do Osso/cirurgia , Humanos , Articulação do Joelho/cirurgia , Masculino , Estudos Retrospectivos , Resultado do Tratamento
9.
Nat Cell Biol ; 3(9): E216-8, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11533679

RESUMO

The study of cell lineages has been, and remains, of crucial importance in developmental biology. It requires the identification of a cell or group of cells and of all of their descendants during embryonic development. Here, we provide a brief survey of how different techniques for achieving this have evolved over the last 100 years.


Assuntos
Desenvolvimento Embrionário e Fetal , Morfogênese , Sistema Nervoso/embriologia , Animais , Biologia do Desenvolvimento/história , Biologia do Desenvolvimento/tendências , História do Século XX , Sistema Nervoso/citologia
10.
Ophthalmologe ; 118(Suppl 1): 96-101, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33258060

RESUMO

BACKGROUND: More than ever research into changes in the eye caused by long-term space flight is becoming the focus of the international and national space agencies National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and German Aerospace Center (DLR). In addition to space radiation-induced cataract formation considerable eye changes, summarized under space flight-associated neuro-ocular syndrome (SANS), can occur. OBJECTIVE: This article gives an overview of the current state of research and future directions in the field of research concerned with ocular alterations in SANS and presents the relevance for terrestrial ophthalmological research. MATERIAL AND METHODS: An analysis of existing publications on SANS in PubMed and reports on the risk of SANS published by the NASA of the USA was carried out. RESULTS: The reasons for the development of the eye changes in space have not been clarified. Factors such as the increase in intracranial pressure, fluid shifts, hypercapnia and genetic factors are the subject of intensive research efforts. A terrestrial model for the induction of papilledema could be established (bed rest studies with -6° head-down tilt as a space analogue). Countermeasures for the development of eye changes, such as intermittent artificial gravity, are the subject of current research studies. CONCLUSION: Research into SANS as part of bed rest studies will provide further important insights in the future for space research and also for terrestrial research. Clinical research projects can be derived from space research.


Assuntos
Papiledema , Voo Espacial , Olho , Humanos , Pressão Intracraniana , Visão Ocular
11.
J Reprod Immunol ; 145: 103320, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33962140

RESUMO

Preeclampsia still represents a life-threatening pregnancy complication, associated with severe maternal and neonatal morbidity and mortality. Low-dose Aspirin is advised to avoid preeclampsia in high-risk pregnancies worldwide. As Aspirin does not cover all women at risk, the prescription raises questions concerning optimal target population, dosage, and onset of therapy. The aim of this study was to test platelet responsiveness on Aspirin by optical aggegrometry, to gain robust biochemically assessment data of Aspirin in an obstetric cohort. 248 women at high risk for development of preeclampsia were included in the study. Aspirin-prophylaxis was administered either in 100 mg (n = 229) or 150 mg (n = 90) daily. Dosing of 100 mg Aspirin was maintained if testing revealed a sufficient platelet inhibition. If platelet inhibition was insufficient, dosage was increased to 150 mg Aspirin and re-testing was advised. 91 patients (91/229 = 39.7%) presented a sufficient inhibitory Aspirin effect at a dosage of 100 mg, but in 138 patients LTA showed an inadequate Aspirin response (138/229 = 60.3%). In 19 women 150 mg Aspirin was administered as starting dose due to new recommendations. Of all women at 150 mg Aspirin 64 did not properly respond (35.4%). The overall rate of sufficient responding women regardless the Aspirin dose was 64.6%. This study demonstrates still an insufficient inhibition of platelet aggregation in about 1/3 of women even with a dosage of 150 mg Aspirin daily, who might potentially benefit from further increase. These data show, that there is a need for further research to allow a personalized approach for individualized Aspirin therapy, maximizing the preventive benefit for mother and child.


Assuntos
Aspirina/administração & dosagem , Plaquetas/efeitos dos fármacos , Inibidores da Agregação Plaquetária/administração & dosagem , Pré-Eclâmpsia/prevenção & controle , Adulto , Plaquetas/imunologia , Relação Dose-Resposta a Droga , Feminino , Humanos , Agregação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/imunologia , Pré-Eclâmpsia/sangue , Pré-Eclâmpsia/imunologia , Gravidez , Gravidez de Alto Risco/sangue , Gravidez de Alto Risco/efeitos dos fármacos , Gravidez de Alto Risco/imunologia , Fatores de Risco
12.
Gut ; 58(12): 1662-9, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19671541

RESUMO

BACKGROUND AND AIMS: Hepatitis C virus (HCV) genotype 4 (HCV-4) is increasing in prevalence in Western countries. However, little is known about the severity of the disease and response to treatment. The aim of this study was to assess the predictors (logistic regression) of severe fibrosis (METAVIR score F3-F4), and sustained virological response (SVR) to peginterferon and ribavirin in 226 consecutive HCV-4 patients (Egyptians 40%, Europeans 35% and Africans 24%). PATIENTS AND METHODS: Insulin resistance was assessed using the homeostasis model (HOMA-IR). Serum HCV-RNA level (bDNA) and subtypes of HCV (LiPA) were determined for all patients. RESULTS: Insulin resistance (HOMA-IR >3) was present in 105 patients (46%), and was associated with: age >45 years (OR, 2.614; 95% CI, 1.316 to 5.194), body mass index (BMI) >25 kg/m(2) (OR, 2.105; 95% CI, 1.048 to 4.229), serum HCV-RNA >800 000 IU/ml (OR, 3.143; 95% CI, 1.503 to 6.574), severe fibrosis (OR, 2.657; 95% CI, 1.214 to 5.818), and steatosis >30% (OR, 2.488; 95% CI, 1.105 to 5.602). Severe fibrosis was present in 67 patients (29%) and was associated with Egyptian origin (OR, 5.872; 95% CI, 2.747 to 12.553), excessive alcohol intake (OR, 5.311; 95% CI, 1.287 to 21.924), and HOMA-IR >3 (OR, 3.864; 95% CI, 1.859 to 8.034). 108 patients received a 48 week course of peginterferon plus ribavirin. SVR (undetectable serum HCV-RNA (TMA) 24 weeks after treatment stopping) was achieved in 59 patients (55%) and was associated with Egyptian origin (OR, 13.119; 95% CI, 3.089 to 55.706), HOMA-IR <2 (OR, 5.314; 95% CI, 1.953 to 14.459), and non-severe fibrosis (OR, 8.059; 95% CI, 2.512 to 25.855). CONCLUSION: Insulin resistance and geographical origin are major predictors of liver fibrosis and response to peginterferon and ribavirin in HCV-4 patients. Insulin resistance is frequently encountered in these patients, and correlated independently with serum HCV-RNA.


Assuntos
Antivirais/uso terapêutico , Hepatite C Crônica/complicações , Resistência à Insulina/etnologia , Cirrose Hepática/virologia , Adulto , População Negra/estatística & dados numéricos , Egito/etnologia , Feminino , França/epidemiologia , Hepacivirus/classificação , Hepacivirus/isolamento & purificação , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/etnologia , Hepatite C Crônica/virologia , Humanos , Interferon alfa-2 , Interferon-alfa/uso terapêutico , Cirrose Hepática/etnologia , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis/uso terapêutico , Estudos Prospectivos , RNA Viral/sangue , Proteínas Recombinantes , Ribavirina/uso terapêutico , Resultado do Tratamento
13.
Ophthalmologe ; 117(8): 740-745, 2020 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-32519116

RESUMO

BACKGROUND: Ocular changes in astronauts, particularly the spaceflight associated neuro-ocular syndrome (SANS), pose a medical challenge for which no suitable preventive measures exist. During long-duration spaceflight missions, e.g. to the Moon and Mars, SANS and radiation-induced cataract could affect the health and performance of crews and jeopardize the success of missions. Mechanistic studies and development of preventive measures require suitable terrestrial models. OBJECTIVE: Overview on the most recent research and future plans in space medicine. MATERIAL AND METHODS: Search for relevant publications using PubMed. RESULTS: Bed rest studies at the German Aerospace Center (DLR) demonstrated that strict bed rest in a -6° head down tilt position reproduces changes just like SANS on Earth. This model including creation of optic disc edema is applied in human studies testing influences of artificial gravity through short arm centrifugation as a preventive method. The unique research facility :envihab provides the opportunity to also simulate the ambient conditions of the International Space Station during bed rest studies. CONCLUSION: Future head down tilt bed rest studies will serve to systematically test preventive measures for SANS. Similar investigations would be difficult to realize under real space conditions. Through close collaboration between space medicine and terrestrial ophthalmology, this research can benefit patients on Earth.


Assuntos
Astronautas , Voo Espacial , Olho , Humanos , Papiledema , Visão Ocular
14.
Ophthalmologe ; 117(8): 721-729, 2020 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-32347333

RESUMO

BACKGROUND: More than ever research into changes in the eye caused by long-term space flight is becoming the focus of the international and national space agencies National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and German Aerospace Center (DLR). In addition to space radiation-induced cataract formation considerable eye changes, summarized under space flight-associated neuro-ocular syndrome (SANS), can occur. OBJECTIVE: This article gives an overview of the current state of research and future directions in the field of research concerned with ocular alterations in SANS and presents the relevance for terrestrial ophthalmological research. MATERIAL AND METHODS: An analysis of existing publications on SANS in PubMed and reports on the risk of SANS published by the NASA of the USA was carried out. RESULTS: The reasons for the development of the eye changes in space have not been clarified. Factors such as the increase in intracranial pressure, fluid shifts, hypercapnia and genetic factors are the subject of intensive research efforts. A terrestrial model for the induction of papilledema could be established (bed rest studies with -6° head-down tilt as a space analogue). Countermeasures for the development of eye changes, such as intermittent artificial gravity, are the subject of current research studies. CONCLUSION: Research into SANS as part of bed rest studies will provide further important insights in the future for space research and also for terrestrial research. Clinical research projects can be derived from space research.


Assuntos
Olho , Voo Espacial , Decúbito Inclinado com Rebaixamento da Cabeça , Humanos , Pressão Intracraniana , Papiledema
15.
Ophthalmologe ; 117(8): 730-739, 2020 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-32399617

RESUMO

BACKROUND: Human intraocular pressure (IOP) depends on the position of the head in relation to the body in space. Physiologically, the IOP increases in a lying position compared to an upright posture. Microgravity in space also appears to cause an increase in intraocular pressure, accompanied by other ophthalmological changes, which are summarized under the term spaceflight associated neuro-ocular syndrome (SANS). Bed rest studies are being carried out to investigate the effects of weightlessness on the human body. So here there is an intersection between research into SANS and glaucoma. Increased intraocular pressure remains the most important risk factor for glaucoma development and progression that can be influenced by treatment. The influence of position-dependent IOP fluctuations on glaucoma is still not sufficiently understood. MATERIALS AND METHODS: A literature search was carried in PubMed on the subject of IOP fluctuations related to posture. Analysis and evaluation of the published study results and a summary of available clinical data. RESULTS: The increase in IOP when changing from a seated to a lying body position is greater in glaucoma patients with an increase of up to 8.6 mm Hg compared to healthy subjects with an increase up to 5 mm Hg. In small pilot studies the increase in lying IOP in some glaucoma patients and healthy volunteers could be attenuated by elevation of the head by 30%. A lower compartmental pressure in the subarachnoid space has been associated with glaucoma and may represent a risk factor for glaucoma development. Not only the level of IOP but also IOP fluctuations were associated with an increased risk of disease progression. CONCLUSION: The clinical significance of IOP peaks during sleep on glaucoma is still not sufficiently understood. New methods for continuous IOP measurement offer promising opportunities for further research into the importance of IOP fluctuations related to changes of body and head posture.


Assuntos
Glaucoma , Pressão Intraocular , Olho , Humanos , Postura , Tonometria Ocular
17.
Science ; 206(4418): 569-71, 1979 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-573921

RESUMO

The electrical fields above chick embryos were explored with a vibrating probe. These fields indicate that steady currents with exit densities of the order of 100 microamperes per square centimeter leave the whole streak and return elsewhere through the epiblast. The epicenter of these strong exit currents lies near Hensen's node. They are probably pumped into the intraembryonic space by the epiblast and then leak out of the streak because it is a zone of junctional disruption.


Assuntos
Embrião de Galinha/fisiologia , Animais , Condutividade Elétrica , Eletricidade , Feminino , Camadas Germinativas/fisiologia , Membrana Vitelina/fisiologia
18.
Science ; 260(5116): 1917-8, 1993 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-17836721

RESUMO

The crystal structure of a stable silyl cation, triethylsilylium, in the form of its tetrakis (pentafluorophenyl)borate salt [Et(3)Si(+) (C(6)F(5))(4)B(-)] (Et, ethyl) shows no coordination between cation and anion. The closest silicon-fluorine distance is greater than 4 angstroms. A toluene solvent molecule is close enough to cause some deviations from planarity at the silicon, but the silicon-toluene distance is well beyond the sum of the silicon and carbon covalent radii. The toluene molecule is essentially planar and undistorted, as expected if little or no positive charge has been transferred from silicon to toluene.

19.
Psychopharmacology (Berl) ; 236(1): 201-226, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30604182

RESUMO

RATIONALE: Aversive learning and memory are essential to cope with dangerous and stressful stimuli present in an ever-changing environment. When this process is dysfunctional, however, it is associated with posttraumatic stress disorder (PTSD). The endocannabinoid (eCB) system has been implicated in synaptic plasticity associated with physiological and pathological aversive learning and memory. OBJECTIVE AND METHODS: The objective of this study was to review and discuss evidence on how and where in the brain genetic or pharmacological interventions targeting the eCB system would attenuate aversive/traumatic memories through extinction facilitation in laboratory animals and humans. The effect size of the experimental intervention under investigation was also calculated. RESULTS: Currently available data indicate that direct or indirect activation of cannabinoid type-1 (CB1) receptor facilitates the extinction of aversive/traumatic memories. Activating CB1 receptors around the formation of aversive/traumatic memories or their reminders can potentiate their subsequent extinction. In most cases, the effect size has been large (Cohen's d ≥ 1.0). The brain areas responsible for the abovementioned effects include the medial prefrontal cortex, amygdala, and/or hippocampus. The potential role of cannabinoid type-2 (CB2) receptors in extinction learning is now under investigation. CONCLUSION: Drugs augmenting the brain eCB activity can temper the impact of aversive/traumatic experiences by diverse mechanisms depending on the moment of their administration. Considering the pivotal role the extinction process plays in PTSD, the therapeutic potential of these drugs is evident. The sparse number of clinical trials testing these compounds in stress-related disorders is a gap in the literature that needs to be addressed.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Canabinoides/uso terapêutico , Transtornos de Estresse Pós-Traumáticos/tratamento farmacológico , Transtornos de Estresse Pós-Traumáticos/psicologia , Tonsila do Cerebelo/efeitos dos fármacos , Tonsila do Cerebelo/metabolismo , Animais , Aprendizagem da Esquiva/fisiologia , Canabinoides/farmacologia , Extinção Psicológica/efeitos dos fármacos , Extinção Psicológica/fisiologia , Medo/efeitos dos fármacos , Medo/fisiologia , Medo/psicologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Humanos , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/fisiologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Transtornos de Estresse Pós-Traumáticos/metabolismo
20.
Neuron ; 4(1): 11-20, 1990 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2155629

RESUMO

The segmented pattern of peripheral spinal nerves in higher vertebrates is generated by interactions between nerve cells and somites. Neural crest cells, motor axons, and sensory axons grow exclusively through anterior-half sclerotome. In chick embryos, posterior cells bind the lectins peanut agglutinin (PNA) and Jacalin. When liposomes containing somite extracts are applied to cultures of chick sensory neurons, growth cones collapse abruptly, recovering within 4 hr of liposome removal. Collapse activity is eliminated by immobilized PNA, and SDS-PAGE demonstrates two major components (48K and 55K), which are absent from anterior-half sclerotome. Rabbit polyclonal antibodies against these components recognize only posterior cells and may also be used to eliminate collapse activity. We suggest that spinal nerve segmentation is produced by inhibitory interactions between these components and growth cones.


Assuntos
Axônios/fisiologia , Gânglios Espinais/fisiologia , Glicoproteínas de Membrana/fisiologia , Receptores Mitogênicos/fisiologia , Animais , Divisão Celular , Células Cultivadas , Embrião de Galinha , Cromatografia de Afinidade , Gânglios Espinais/embriologia , Histocitoquímica , Imuno-Histoquímica , Glicoproteínas de Membrana/isolamento & purificação , Mesoderma/metabolismo , Mesoderma/fisiologia , Receptores de Superfície Celular/metabolismo , Receptores Mitogênicos/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA