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BACKGROUND: Intermittent catheterization (IC) has been identified as one of the critical techniques used by spinal cord injury (SCI) patients to cope with emptying the bladder, despite several problems impeding this procedure. AIM: The study aimed accordingly to explore the lived experience of Arab male patients on IC after their SCI. DESIGN: This study was carried out by using a descriptive qualitative approach with a phenomenological analysis of data. METHODS: A qualitative study was carried out on 10 Arab male patients from the Rehabilitation Hospital at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia who were utilizing intermittent catheters following SCI. The interviews were analysed using Husserl's phenomenology and the Colaizzi method of data analysis. RESULTS: Two major themes and six sub-themes were identified from exploring the patients experience. These themes are as follows: Theme 1: The Way to IC; with two sub-themes: (i) 'service provided and acceptance' and (ii) 'educational experience'; Theme 2: Lifestyle and self-adaptation; with four sub-themes: (i) 'Flexibility and freedom', (ii) 'Physical access to the community', (iii) 'Traveling' and (iv) 'Work and Social life balance'. CONCLUSION: It is evident that using an intermittent catheter among patients with SCI influenced almost all aspects of the participant's life, including their social lives and body image appearance.
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AIM: To assess the knowledge, attitudes, and practices of Palestinian nursing students towards pressure injury prevention. MATERIALS AND METHODS: A descriptive cross-sectional study was conducted with 455 nursing students recruited from Arab American University-Palestine, employing a total population sample. Data collection forms include socio-demographic information, the Pressure Ulcer Knowledge Assessment Tool, Attitude towards Pressure Ulcer Prevention Instrument and Pressure Injury Preventive Practices scale. RESULTS: The study found that students had a mean knowledge score of 54% (14.04/26), a positive attitude score of 75.8% (39.42/52), and demonstrated a fair level of practice 75.3% (30.12/40). Significant differences were observed in the Knowledge, Attitude, and Practice total scores, linked to academic year, clinical experience, and the number of attended departments during clinical training (p < 0.001). Additionally, weak but significant positive relationships were found between practice and attitude scores (r = 0.303, p < 0.001), practice and knowledge score (r = 0.211, p < 0.001), and a moderate positive significant relationship between knowledge and attitude scores (r = 0.567, p < 0.001). CONCLUSION: The study revealed insufficient knowledge, positive attitudes, and somewhat unsafe practices among nursing students regarding pressure injury prevention. It highlights the need for specific revisions in the nursing curriculum. Improvements can be achieved through detailed coverage in classrooms and laboratories, integrating simulation methods. Additionally, ensuring that students gain adequate experiences in clinical units, with a specific emphasis on pressure injury prevention, is crucial for improving students' capability and contribute to better pressure injury management.
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Árabes , Conhecimentos, Atitudes e Prática em Saúde , Úlcera por Pressão , Estudantes de Enfermagem , Humanos , Úlcera por Pressão/prevenção & controle , Estudantes de Enfermagem/estatística & dados numéricos , Estudantes de Enfermagem/psicologia , Estudos Transversais , Masculino , Feminino , Árabes/estatística & dados numéricos , Árabes/psicologia , Adulto , Inquéritos e Questionários , Adulto JovemRESUMO
Objectives: This "2-arm parallel" trial investigated the recall of information pertinent to obtaining informed consent of parents of orthodontic patients using; either written material and verbal support or an animation. Materials and methods: Parents of patients, aged 12-18 years, about to undergo fixed applaince treatment, were randomized to either receive information by leaflet or by watching an animation. The parents were asked a series of open-ended questions immediately and one year later. The outcome measure was the total median questionnaire score immediately (T0) and one year later (T1). A Mann Whitney U test was performed to test for differences between T0 and T1. Results: 31 parents were randomized into the leaflet group and 33 in to the animation group. The median leaflet group score was 81 (IQR = 27) at the time of consent (T0) and 87 (IQR = 29) a year later (T1), compared to a median score of 76 (IQR = 23) for the animation group at T0 and 87 (IQR = 32) at T1. Statistically, there was no difference in the questionnaire score at (T0) (p = 0.567) and at (T1) (p = 0.522). The average time spent with the clinician in the leaflet group was an additional 9 min in the animation group. Conclusion: The use of a leaflet and verbal information or an animation are equivalent in providing information to the parents of orthodontic patients. The use of an animation reduces the clinical time needed to deliver the information.
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This study was intended to determine the characteristics of Medical Related Pressure Injury (MDRPI) in adult intensive care patients. MDRIs are recognized as significant and complex health problems among hospitalized patients. Underestimated true scale of the problem is evident because the systematic clinical evaluation of MDRPI occurrence is not part of routine skin assessment among intensive care patients. A prospective approach was used to obtain data of MDRPIs with two weeks follow up to monitor the prevention and treatment strategies. Participants were 329 adult patients from three large referral and teaching centres in Jordan. Data were collected using a screening form that included demographic and clinical characteristics, and a list of medical devices. The primary outcome for this study was MDRPI and defined as a pressure injury (PI) found on the skin or mucous membrane with a medical device in use at the location of the injury (EPUAP, 2019). The patients with MDRPI were followed up for 2 weeks for prevention and treatment strategies. Prevalence of MDRPI was 5.01% (15/299) with 41 injuries, 27/41 (65.8%) were skin injuries and 14/41(34.2%) were mucosal. Most mucous membrane MDRPIs were at mouth/lips and caused by ET tube and meatal orifice caused by foley catheter. Skin MDRPIs were at the nose and caused by NG tube and hands by peripheral intravenous line and arms caused by blood pressure cuff. Inadequate prevention was provided on daily care as only 177 prevention and treatment interventions were provided over 2 weeks for 15 patients. As a growing problem among Jordanian adults in intensive care, MDRPI required the need for effective prevention. About one-thirds of MDRPIs were mucosal, a finding not previously reported, indicating the need to include mucous membrane assessment with skin assessment when a medical device such as NG and ET tubes or foley catheters are in use. Prevention and treatment interventions provided to patients with MDRPIs were not systematic and based on routine care with no clear guidelines. A consensus has yet to be reached suggesting the need to establish effective prevention strategies for medical device-related pressure injuries. Future research is recommended to follow up MDRPI prevention and treatment strategies among patients in ICU. We suggest to continue studying the prevalence of MDRPIs and monitoring the location, prevention and treatment of both skin and mucosal MDRPIs.
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Úlcera por Pressão , Humanos , Adulto , Prevalência , Úlcera por Pressão/epidemiologia , Úlcera por Pressão/etiologia , Úlcera por Pressão/terapia , Cuidados Críticos , Pressão , Estudos ProspectivosRESUMO
INTRODUCTION: The objective of this 2-arm parallel trial was to investigate the recall and comprehension of the information of orthodontic patients undergoing fixed orthodontic treatment using either the verbal explanation supported with the British Orthodontic Society (BOS) leaflet or 3-dimensional (3D) animated content. METHODS: Patients aged 12-18 years, with no relevant medical history or learning and reading difficulties, who were to undergo orthodontic treatment, were randomized to receive information about fixed orthodontic treatment, using either verbal explanation supported with the BOS leaflet or 3D animated content on the basis of the BOS leaflet. Randomization was performed by block randomization; block size of 4 was used, from which 6 blocks with 6 different sequences (AABB, ABBA, ABAB, BBAA, BAAB, BABA). The blinded author asked patients a series of open-ended questions. The primary outcome measure was the total score of the questions. An independent 2 sample t test was conducted to determine if there was a statistical difference in total questions score between the conventional method (verbal and leaflet) and the 3D animation at the time of consent taking (T0) and again 1 year later (T1). The secondary outcome measure was the time spent by the clinician delivering the information to the patient. RESULTS: Thirty-two patients were randomized into each group. After 1 year, 1 patient was lost in each group. At the time of consent, the conventional group scored 79.1 ± 18.4 compared with 76.4 ± 12.8 for the 3D animation group with no statistically significant difference (95% confidence interval, -11.0 to 5.3), (P = 0.492). One year later, again, there was no statistically significant difference (P = 0.639) between the conventional group (75.6 ± 12.3) and the 3D animation group (74.4 ± 9.0) (95% confidence interval, -7.0 to 4.4). The average exposure time to the educational intervention in the conventional group was 8.5 minutes more than the 3D animation group. CONCLUSIONS: The use of 3D animation or verbal and leaflet information is relatively equivalent in transferring knowledge to the orthodontic patient. The use of a 3D animated video reduces the clinician time needed in the clinic to deliver information to the patients and also allows multiple views and better suits the younger generation. Patients undergoing short- or long-term orthodontic treatment do not recall root damage as a risk of orthodontic treatment, which requires special attention from the orthodontist to reinforce this information. REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement.
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Compreensão , Educação de Pacientes como Assunto , Técnicas de Movimentação Dentária , Adolescente , Humanos , Sociedades Odontológicas , Gravação em VídeoRESUMO
BACKGROUND: Human beings have an inbuilt desire to care and nurture others. In some professions such as nursing, women are perceived as privileged in relation to these traits, and women are in the majority in the nursing profession. The Gender theory suggests that men should adapt to feminine traits and nature in order to fit in the nursing profession. However, there is a paucity of literature in relation to Arab male nurses' experience in nursing. PURPOSE: The purpose of this study was to explore the Jordanian male nurses' experiences of their career within their Arabic community. METHODS: A hermeneutic phenomenological approach, underpinned by VanManen's perspective was used. Twenty-two Jordanian male nurses were approached from four hospitals in Jordan. Four focus groups comprising 5-6 interviewees in each were used. The focus groups were audio-recorded and transcribed verbatim. The data were analyzed using Van Manen's hermeneutic approach and themes extracted from the Arabic version were compared critically with the analysis of the English version to develop the meaning of the narratives. DISCUSSION: Three major themes emerged from the data: (i) personal gains; (ii) masculinity; (iii) and cultural influences. Whilst male nurses recognized nursing is a female dominant profession, they viewed themselves as more independent in decision making and more productive than their female counterparts. Significantly, the participants described nursing as a means of fulfilling their spiritual needs and thus a personal gain. The interviewees linked their masculinity to resilience and endurance. Participants described that men in nursing face some social constraints within the Arab community. CONCLUSION: The study findings partly supported the fact that nursing in Jordan is a predominantly female profession which lends support to the gender theory in which Jordanian male nurses experienced a social bias and disadvantages by Arabic culture stereotypes of a male nurse. Although nursing is still a feminine career, the findings of this study raise awareness that gender role stereotype might not hold a strong stance in relation to nursing and that could be attributed to elements such as economic and payment status.
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Árabes/psicologia , Atitude do Pessoal de Saúde , Enfermeiros/psicologia , Adulto , Características Culturais , Grupos Focais , Identidade de Gênero , Humanos , Jordânia , Masculino , Pessoa de Meia-Idade , Enfermeiros/estatística & dados numéricos , Pesquisa Qualitativa , EstereotipagemRESUMO
AIMS AND OBJECTIVES: To assess nurses' knowledge on pressure ulcer (PU) prevention and treatment in Jordan, and the frequency of and factors influencing nurses' implementation of PU prevention and treatment interventions. BACKGROUND: Highly educated and experienced nurses can provide effective PU care; however, previous studies highlighted poor knowledge and implementation of PU care. DESIGN: A correlational study examining nurses' knowledge of PU prevention and frequency of PU preventive actions in Jordanian hospitals. METHODS: Participants were 377 nurses and 318 patients from 11 hospitals. Data were collected to quantify the frequency of nurses' implementation of pressure ulcer prevention and treatment interventions for patients suffering from PUs and/or at risk of PU development using a self-reported cross-sectional survey and prospective 8-h observation. RESULTS: For observed PU prevention while type of hospital and number of beds in units were significant it is not known without further work if this is replicable. For observed PU treatment, linear regression analysis revealed significant negative beta values for more than 50 beds in clinical unit (ßâ¯=â¯-2.49). CONCLUSION: The study addressed new factors, facilitating the provision of prevention and treatment strategies to PU development, including type of clinical institution and number of beds in clinical unit. RELEVANCE TO CLINICAL PRACTICE: There is a need to develop training programmes to improve insufficient nurses' knowledge and, thus, clinical practices on PU prevention and treatment. These programmes would assist both junior and senior nurses and other key stakeholders (e.g. hospital managers, policy-makers, and educators) to improve the performance of PU services, thus, minimising patient suffering.
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Competência Clínica/normas , Enfermeiras e Enfermeiros/normas , Úlcera por Pressão/prevenção & controle , Adulto , Idoso , Idoso de 80 Anos ou mais , Competência Clínica/estatística & dados numéricos , Correlação de Dados , Estudos Transversais , Feminino , Humanos , Jordânia , Masculino , Pessoa de Meia-Idade , Enfermeiras e Enfermeiros/estatística & dados numéricos , Úlcera por Pressão/enfermagem , Estudos Prospectivos , Autorrelato , Higiene da Pele/enfermagemRESUMO
PURPOSE: To determine the prevalence of depression and anxiety among otolaryngology outpatients at Jordan University Hospital. METHODS: A cross-sectional observational study was conducted between January 2017 and February 2018. The sample included 1328 otolaryngology adult outpatients, who completed (PHQ-9) and (GAD-7) questionnaires for depression and anxiety. Sociodemographic and clinical data were recorded. RESULTS: Depression and anxiety prevalence rates were 36.1% and 22.9%. The significant risk factors found for them were: age range 30 to 50 years, female sex, divorced status, smoking, alcohol drinking, asthma, family history of psychiatric illness, chronic illnesses, negative life events, secondary education, unemployment, low income, globus pharyngeus, tinnitus, and dizziness. PRACTICE IMPLICATIONS: Healthcare providers should have the vigilance to suspect and treat these disorders to improve patients' symptoms and quality of life.
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Ansiedade/epidemiologia , Depressão/epidemiologia , Otorrinolaringopatias/psicologia , Adulto , Idoso , Ansiedade/complicações , Estudos Transversais , Depressão/complicações , Feminino , Hospitais Universitários , Humanos , Jordânia/epidemiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Otorrinolaringopatias/complicações , Pacientes Ambulatoriais , Prevalência , Escalas de Graduação Psiquiátrica , Qualidade de Vida , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
BACKGROUND: An increased number of elderly people in the world may lead to an increase in the incidence of stroke, which creates a burden on the country's healthcare system. Dysphagia is the most common post stroke. Screening of dysphagia in stroke patients is serious to prevent complication linked to aspiration and inadequate hydration/nutrition. OBJECTIVE: This literature review aimed to discuss registered nurses' competency to screen dysphagia among stroke patients. METHODS: The keywords used were nurse's competency; dysphagia; dysphagia screening; and stroke. These keywords were entered into multiple electronic databases including CINAHL, Medline, Science Direct, Pro Quest, Pub Med, and Wiley Online Library. Aliterature search was conducted for the period2005 to 2016.Results:Seventeen studies were identified by a systematic search ofthe literature.Two parts created the body of this literature review. The first part covers the literature on the training nurses in screening dysphagia among stroke patients and benefits of screening. The second part covers nurse's competency in terms of knowledge and skills of screening dysphagia among stroke patients. CONCLUSION: Because the nurses have more contact with the patient, they are most likely to observe dysphagia. It is important that formal dysphagia screening protocols are routine nursing care that requires special training to practice. Trained nurses should assess their competency in terms of knowledge and skills via well-developed tool.
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BACKGROUND: Nurses from various setting lack sufficient knowledge about diabetes and diabetes management. Better understand of evidence-based practices by nurses who are involved in caring for hospitalized individuals with diabetes can positively influence care outcomes. METHOD: A pretest design was used to evaluate the effectiveness of a diabetes education program for RNs working voluntarily participated. A 1-day education program was developed and delivered to the participating nurses. Knowledge regarding diabetes was tested before and after the education program. RESULTS: a significant difference was noted in the modified diabetes basic knowledge mean test scores before and after implementation of the education program (t[128] = 17.95, P < 0.001). CONCLUSIONS: The diabetes education program had a positive on nurses' knowledge. This finding has implications for developing diabetes education content within nursing curricula, as well as continuing education courses for practicing nurses.
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Diabetes Mellitus/enfermagem , Educação Continuada em Enfermagem/organização & administração , Avaliação Educacional , Enfermagem Baseada em Evidências/educação , Avaliação de Processos e Resultados em Cuidados de Saúde/estatística & dados numéricos , Adulto , Currículo , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Enfermeiras e Enfermeiros , Avaliação de Programas e Projetos de Saúde , Estados Unidos , Adulto JovemRESUMO
AIMS: The aims of the study were to determine: (1) Jordanian nurses' level of knowledge of pressure ulcer prevention and treatment of hospitalized patients based on guidelines for pressure ulcer prevention and treatment. (2) Frequency of utilization of pressure ulcer prevention and treatment interventions in clinical practice. (3) Variables that are associated with nurses' utilization of pressure ulcer prevention and treatment interventions. BACKGROUND: Pressure ulcers are common and previous studies have shown education, knowledge and attitude affect implementation of interventions. METHODS: A cross-sectional survey design was used to collect data from 460 nurses between June 2010 and November 2010. We used a questionnaire, which was informed by earlier work and guidelines, to collect data about nurses' knowledge and practice of pressure ulcer prevention and treatment. RESULTS/FINDINGS: Knowledge and education show an association with implementation of prevention, and demographic variables do not. Similarly knowledge and type of hospital showed an association with implementing treatment. Of concern the use of "donuts" and massage are reported in use. CONCLUSION: Although pressure ulcer care is well known by nurses, inappropriate pressure ulcer interventions were reported in use.
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Conhecimentos, Atitudes e Prática em Saúde , Recursos Humanos de Enfermagem Hospitalar , Úlcera por Pressão , Adulto , Estudos Transversais , Feminino , Humanos , Jordânia , Masculino , Úlcera por Pressão/enfermagem , Úlcera por Pressão/prevenção & controle , Úlcera por Pressão/terapia , Inquéritos e QuestionáriosRESUMO
PURPOSE: The authors implemented and evaluated a preceptor training program to prepare registered nurses to become preceptors and to establish a nursing preceptor training program to promote knowledge of preceptorship among Jordanian nurses. METHODS: A true experimental design was used. The sample consisted of 68 registered nurses recruited randomly from governmental, private, and university hospitals. A sociodemographic data form and a questionnaire on nurses' knowledge about preceptorship were developed for self-administration. RESULTS: The study results showed that the difference between the experimental (n = 30, M = 33/41, SD = 4.5) and control (n = 38, M = 26/41, SD = 4.6) groups after implementation of the preceptorship program was statistically significant (t = 5.5, df = 66, p = .000). CONCLUSION: The preceptorship program showed significant improvement in participants' knowledge of clinical teaching.
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Enfermeiras e Enfermeiros , Preceptoria , Humanos , Jordânia , Inquéritos e QuestionáriosRESUMO
BACKGROUND: It is essential for all university leaders to develop and maintain an effective programme of total quality management in a climate that promotes work satisfaction and employee support. PURPOSE: The purpose of the study was to investigate the relationship of faculty members' organizational commitment to their job satisfaction, perceived organizational support, job autonomy, workload, and pay. METHODS: A quantitative study, implementing a correlational research design to determine whether relationships existed between organizational commitment and job satisfaction, perceived organizational support, job autonomy, workload and pay. RESULTS: Stepwise linear regression analysis was used to estimate the probability of recorded variables included significant sample characteristics namely, age, experience and other work related attributes. The outcome showed a predictive model of three predictors which were significantly related to faculty members' commitment: job satisfaction, perceived support and age. CONCLUSION: Although the findings were positive toward organizational commitment, continued consideration should be given to the fact that faculty members remain committed as the cost associated with leaving is high. IMPLICATION FOR NURSING MANAGEMENT: A study of this nature increases the compartment in which faculty administrators monitor the work climate, observe and identify factors that may increase or decrease job satisfaction and the work commitment.
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Docentes de Enfermagem , Satisfação no Emprego , Liderança , Motivação , Apoio Social , Universidades , Adulto , Análise de Variância , Eficiência Organizacional , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Enfermagem , Modelos Organizacionais , Modelos Psicológicos , Autonomia Pessoal , Setor Público/economia , Setor Público/organização & administração , Estatística como Assunto , Universidades/economia , Universidades/organização & administração , Recursos Humanos , Carga de TrabalhoRESUMO
BACKGROUND: The effects of student-faculty interactions in higher education have received considerable empirical attention. However, there has been no empirical study that has examined the relation between student-faculty interaction and college grade point average. PURPOSE: This is aimed at identifying the effect of nursing student-faculty interaction outside the classroom on students' semester college grade point average at a public university in Jordan. METHODS: The research was cross-sectional study of the effect of student-faculty interaction outside the classroom on the students' semester college grade point average of participating juniors and seniors. RESULTS: Total interaction of the students was crucial as it is extremely significant (t = 16.2, df = 271, P ≤ 0.001) in relation to students' academic scores between those students who had ≥70 and those who had <70 academic scores. However, gender differences between students, and other variables were not significant either to affect students' academic scores or students' interaction. CONCLUSION: This study provides some evidence that student-faculty interactions outside classrooms are significantly associated with student's academically achievements.
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Bacharelado em Enfermagem , Avaliação Educacional/estatística & dados numéricos , Docentes de Enfermagem , Relações Interprofissionais , Estudantes de Enfermagem , Adulto , Estudos Transversais , Feminino , Humanos , Jordânia , Masculino , Setor Público , Escolas de Enfermagem , Estudantes de Enfermagem/estatística & dados numéricos , Adulto JovemRESUMO
The aetiology of neuroblastoma remains obscure, although a number of neuropeptides have been implicated in its pathogenesis. Using the mouse neuroblastoma cell line Neuro2a as a model, we have investigated the mitogenic actions of prolactin (PRL) and two hypothalamo-pituitary-adrenal stress axis hormones, corticotropin-releasing factor (CRF) and corticosterone. Using established polyclonal PRL receptor antisera with immunofluorescence cytochemistry, we show that the Neuro2a cells possess immunoreactive forms of both the long and short forms of the receptor. PRL and CRF were effective as mitogens in Neuro2a cell cultures, where a 10(-7) M concentration of PRL or CRF elicited a two-fold increase in the numbers of cells after 72 h (p < 0.0001). Corticosterone, however, attenuated their proliferation. These data suggest that prolactin may act to increase the proliferation and regulation of neuroblastomas and that the effects of PRL may be modified by hypothalamo-pituitary-adrenal hormones.
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Corticosterona/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Neuroblastoma/metabolismo , Prolactina/metabolismo , Receptores da Prolactina/genética , Animais , Sequência de Bases , Divisão Celular/fisiologia , Camundongos , Microscopia Confocal , Dados de Sequência Molecular , Neuroblastoma/imunologia , RNA Mensageiro , Receptores da Prolactina/biossíntese , Receptores da Prolactina/imunologiaRESUMO
Gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus is pivotal to the regulation of reproductive physiology in vertebrates. GnRH and the reproductive axis, in general, can be inhibited during periods of stress or injury. Stress, in the form of mechanical, psychological or immunological insult to an organism results in the activation of the hypothalamo-pituitary-adrenal (HPA) axis initiated by the hypothalamic release of corticotropin-releasing factor (CRF). Recent studies indicate that CRF may act either directly on the GnRH neuron to down-regulate GnRH synthesis, or indirectly via a beta-endorphin-mediated pathway. Moreover, in vitro studies suggest that CRF-related peptides can increase the sensitivity of the GnRH neuron to prolactin by increasing the synthesis of the prolactin receptor.
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Glândulas Suprarrenais/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Hipófise/metabolismo , Animais , Hormônio Liberador da Corticotropina/metabolismo , Regulação para Baixo , Humanos , Microscopia Confocal , Modelos Biológicos , Prolactina/metabolismo , Receptores da Prolactina/metabolismo , Estresse Fisiológico , beta-Endorfina/metabolismoRESUMO
The role of the circadian clock in the reproductive development of Syrian hamsters (Mesocricetus auratus was examined in wild type and circadian tau mutant hamsters reared from birth to 26 weeks of age under constant dim red light. Testis diameter and body weights were determined at weekly intervals in male hamsters from 4 weeks of age. In both genotypes, testicular development, subsequent regression and recrudescence exhibited a similar time course. The age at which animals displayed reproductive photosensitivity, as exhibited by testicular regression, was unrelated to circadian genotype (mean +/- SEM: 54 +/- 3 days for wild type and 59 +/- 5 days for tau mutants). In contrast, our studies revealed a significant impact of the mutation on somatic growth, such that tau mutants weighed 18% less than wild types at the end of the experiment. Our study reveals that the juvenile onset of reproductive photoperiodism in Syrian hamsters is not timed by the circadian system.
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Ritmo Circadiano/fisiologia , Mesocricetus/crescimento & desenvolvimento , Fotoperíodo , Testículo/crescimento & desenvolvimento , Proteínas tau/genética , Análise de Variância , Animais , Peso Corporal , Cricetinae , Escuridão , Genótipo , Masculino , Mesocricetus/genética , Mesocricetus/fisiologia , Mutação , Testículo/fisiologiaRESUMO
Corticotropin-releasing factor and urocortin belong to a superfamily of neuropeptides that includes the urotensins-I in fishes and the insect diuretic peptides. Sequence analysis suggests that urocortin is the mammalian ortholog of urotensin-I, although the physiological role for this peptide in mammals is not known. Within the Rodentia, hamsters belong to a phylogenetically older lineage than that of mice and rats and possess significant differences in hypothalamic organization. We have, therefore, cloned the coding region of the Syrian hamster (Mesocricetus auratus) corticotropin-releasing factor and urocortin mature peptide by polymerase chain reaction. Hamster urocortin was prepared by solid-phase synthesis, and its pharmacological actions on human corticotropin-releasing factor R1 and R2 receptors were investigated. The deduced hamster corticotropin-releasing factor amino acid sequence and cleavage site is identical to that in rat, whereas the urocortin sequence is unique among the urocortin/urotensin-I/sauvagine family in possessing asparagine and alanine in positions 38 and 39, respectively. The hamster urocortin carboxy terminus sequence bears greater structural similarity to the insect diuretic peptide family, suggesting either retrogressive mutational changes within the mature peptide or convergent sequence evolution. Despite these changes, human and hamster urocortin are generally equipotent at cAMP activation, neuronal acidification rate, and R1/R2 receptor affinities.
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Hormônio Liberador da Corticotropina/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Células CHO , Clonagem Molecular , Hormônio Liberador da Corticotropina/metabolismo , Cricetinae , DNA Complementar , Feminino , Humanos , Masculino , Mesocricetus , Dados de Sequência Molecular , Ratos , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Homologia de Sequência de Aminoácidos , UrocortinasRESUMO
The tau mutation is a semi-dominant autosomal mutation which, in homozygotes, accelerates the period of the circadian activity cycle by approximately 4 h. In mammals, the circadian system contributes to seasonal photoperiodic time measurement by generating a repeated daily melatonin signal during the hours of darkness. Our earlier studies suggest an altered response to the melatonin signal in tau mutants. This study investigated whether tau and wild-type hamsters exhibit a differential response to photoperiod change. Reproductively active animals were maintained on stimulatory photoperiods of 16 h light (16L) per 24 h (wild-type) or 12L per 20 h (tau) before being exposed to an increase in night-length to 9, 10, 11, 12 or 14 h for 84 cycles. Wild-types exhibited testicular atrophy at 13L:11Dark (13L:11D), with full regression at photoperiods of 12L:12D. Taus exhibited complete regression at photoschedules comprising 10 h darkness or more per 20-h cycle. Plasma prolactin concentrations were decreased following exposure to at least 9 and 10 h darkness in taus and wild-types, respectively. Thus, the tau genotype may exhibit a different critical night-length with respect to both the gonadal and prolactin axes, of approximately 1-2 h shorter than wild-type genotypes. These data support the hypothesis that the circadian tau mutation has altered the basis of photoperiodic time measurement, perhaps by altering the generation and/or interpretation of the melatonin signal.