RESUMEN
PURPOSE: The aim of the present study was to estimate whether self-assessed mental well-being and work capacity determines future sickness absence (SA). METHODS: A questionnaire was sent to employed individuals (n = 6,140), aged 19-64 years, who were registered as sick-listed with a new sick-leave spell in 2008. The response rate was 54 %. In this study we included individuals with a single sick-leave spell in 2008 (n = 2,502). The WHO (Ten) Well-Being Index and four dimensions of self-assessed work capacity (knowledge, mental, collaborative, physical) were used as determinants. Future sickness absence was identified through national register in 2009. Outcome was defined as no sickness benefit compensated days (no SBCD) and at least one sickness benefit compensated day (SBCD). Logistic regression analyses were used to estimate odds ratios (OR) with 95 % confidence intervals (CI) for the likelihood of SBCD. RESULTS: In 2009, 28 % of the women and 22 % of the men had SBCD; the median was 59 and 66 benefit days, respectively. Individuals with low mental well-being had higher odds for SBCD with OR 1.29 (95 % CI 1.01-1.65) in the fully adjusted model. Participants reporting low work capacity in relation to knowledge (OR 1.55, 95 % CI 1.13-2.13), collaborative (OR 1.36, 95 % CI 1.03-1.79) and physical (OR 1.50, 95 % CI 1.22-1.86) demands at work had higher odds for SBCD after adjustments for all covariates; no relation was demonstrated with mental work capacity (OR 0.99, 95 % CI 0.76-1.27). CONCLUSION: Mental well-being and work capacity emerged as determinants of future SA. Screening in health care could facilitate early identification of persons in need of interventions to prevent future SA.
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Salud Mental , Ausencia por Enfermedad/estadística & datos numéricos , Evaluación de Capacidad de Trabajo , Adulto , Femenino , Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Autoevaluación (Psicología) , Encuestas y Cuestionarios , Adulto JovenRESUMEN
PURPOSE: Middle managers in health care today are expected to continuously and efficiently decide and act in administration, finance, care quality, and work environment, and strategic communication has become paramount. Since dialogical communication is considered to promote a healthy work environment, the purpose of this paper is to investigate the ways in which health care managers experienced observing subordinates' dialogue training. DESIGN/METHODOLOGY/APPROACH: A qualitative study using semi-structured interviews and documents from eight middle managers in a dialogue programme intervention conducted by dialogue trainers. Focus was on fostering and assisting workplace dialogue. Conventional qualitative content analysis was used. FINDINGS: Managers' experiences were both enriching and demanding, and consisted of becoming aware of communication, meaning perceiving interaction between subordinates as well as own silent interaction with subordinates and trainer; Discovering communicative actions for leadership, by gaining self-knowledge and recognizing relational leadership models from trainers--such as acting democratically and pedagogically--and converting theory into practice, signifying practising dialogue-promoting conversation behaviour with subordinates, peers, and superiors. RESEARCH LIMITATIONS/IMPLICATIONS: Only eight managers participated in the intervention, but data afforded a basis for further research. PRACTICAL IMPLICATIONS: Findings stressed the importance of listening, and of support from superiors, for well-functioning leadership communication at work. ORIGINALITY/VALUE: Studies focusing on health care managers' communication and dialogue are few. This study contributes to knowledge about these activities in managerial leadership.
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Comunicación , Administradores de Hospital/educación , Aprendizaje , Conducta Cooperativa , Departamentos de Hospitales , Humanos , Capacitación en Servicio , Liderazgo , Investigación Cualitativa , SueciaRESUMEN
OBJECTIVES: To evaluate the influence of perceived stress and musculoskeletal ache/pain, separately and in combination, at baseline, on self-rated work ability and work performance at two-year follow-up. METHODS: Survey data were collected with a 2-year interval. Health care workers participating at both waves were included. Inclusion criteria were good self-reported work ability and unchanged self-rated work performance at baseline, resulting in 770 participants; 617 women and 153 men. Musculoskeletal pain was assessed using the question "How often do you experience pain in joints and muscles, including the neck and low back?", perceived stress with a modified version of a single item from the QPS-Nordic questionnaire, work performance by the question "Have your work performance changed during the preceding 12 months?" and work ability by a single item from the work ability index. Associations between baseline data and the two outcomes at follow-up were analysed by means of the log binomial model and expressed as risk ratios (RR) with 95% confidence intervals (CI). RESULTS: A combination of frequent musculoskeletal pain and perceived stress constituted the highest risk for reporting decreased work performance (RR 1.7; CI 1.28-2.32) and reduced work ability (RR 1.7; CI 1.27-2.30) at follow-up. Separately, frequent pain, but not stress, was clearly associated with both outcomes. CONCLUSION: The results imply that proactive workplace interventions in order to maintain high work performance and good work ability should include measures to promote musculoskeletal well-being for the employees and measures, both individual and organizational, to minimize the risk of persistent stress reactions.
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Personal de Salud/psicología , Dolor Musculoesquelético/psicología , Estrés Psicológico/psicología , Análisis y Desempeño de Tareas , Trabajo/psicología , Adulto , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Encuestas Epidemiológicas , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Factores de Riesgo , Autoinforme , Encuestas y Cuestionarios , SueciaRESUMEN
PURPOSE: Leadership can positively affect the work environment and health. Communication and dialogue are an important part in leadership. Studies of how dialogue is valued and handled in first-line leadership have not so far been found. The aim of this study is to develop a theoretical understanding of how first-line leaders at hospitals in western Sweden value and handle dialogue in the organisation. DESIGN/METHODOLOGY/APPROACH: The study design was explorative and based on grounded theory. Data collection consisted of interviews and observations. A total of 11 first-line leaders at two hospitals in western Sweden were chosen as informants, and for four of them observation was also used. FINDINGS: One core category emerged in the analysis: leaders' communicative actions, which could be strategically or understanding-oriented, and experienced as equal or unequal and performed equitably or inequitably, within a power relationship. Four different types of communicativeactions emerged: collaborative, nurturing, controlling, and confrontational. Leaders had strategies for creating arenas and relationships for dialogue, but dialogue could be constrained by external circumstances or ignorance of the frameworks needed to conduct and accomplish dialogue. PRACTICAL IMPLICATIONS: First-line leaders should be offered guidance in understanding the consequences of consciously choosing and strengthening the communication component in leadership. ORIGINALITY/VALUE: The positive valuation of dialogue was not always manifest in practical action. One significant consequence of not using dialogue was that information with impact on organisational efficiency and finances was communicated upwards in the management system.
Asunto(s)
Comunicación , Hospitales Públicos , Liderazgo , Adulto , Femenino , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Observación , SueciaRESUMEN
OBJECTIVE: The aim of this study was to assess the construct and predictive validity of a new instrument for self-rating of stress-related Exhaustion Disorder (s-ED). METHODS: Public healthcare workers and social insurance officers, 85% females, were included (N = 2,683) in a longitudinal study. The s-ED instrument, based on clinical criteria for Exhaustion Disorder, was used at baseline to classify participants into three categories: non-s-ED, light/moderate s-ED and pronounced s-ED. Other assessments include burnout, anxiety, depression and work ability. Sick leave at follow-up after 2 years was defined as 14 days of ongoing sick leave (SA14) or a period of 60 days of sick leave during the last 12 months (SA60). Associations at baseline were expressed as prevalence ratios, and adjusted relative risks (RR) were calculated using Cox regression. RESULTS: At baseline, 16% reported s-ED. Scores of depression, anxiety and burnout and the rate of poor work ability increased with increasing severity of s-ED. Self-reported exhaustion at baseline increased the risk of reporting sickness absence at follow-up; pronounced s-ED RR 2.7; CI 1.8-4.0 for SA14 and RR 3.4; CI 2.3-5.2 for SA60. CONCLUSIONS: Self-rated ED corresponded well to established scales for mental health, indicating sufficient construct validity. Individuals reporting s-ED at baseline were more likely to report sickness absence at follow-up, confirming its predictive properties. The s-ED instrument may be a useful tool for occupational health services in identifying human service workers at risk of having or developing a potentially disabling stress-related mental illness.
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Absentismo , Personal de Salud/estadística & datos numéricos , Salud Mental/estadística & datos numéricos , Enfermedades Profesionales/epidemiología , Seguridad Social/estadística & datos numéricos , Encuestas y Cuestionarios , Adulto , Ansiedad/epidemiología , Agotamiento Profesional/epidemiología , Depresión/epidemiología , Fatiga/epidemiología , Fatiga/psicología , Femenino , Conductas Relacionadas con la Salud , Personal de Salud/psicología , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Prevalencia , Reproducibilidad de los Resultados , Factores Socioeconómicos , Suecia/epidemiología , Lugar de Trabajo/psicología , Lugar de Trabajo/estadística & datos numéricosRESUMEN
OBJECTIVE: The aim of this study was to determine the physiologic role for endogenous endothelin in the regulation of vascular tone during normal pregnancy and preeclampsia. The vascular sensitivity to endothelin-1 during pregnancy was studied also. STUDY DESIGN: Forearm blood flow was measured by venous occlusion plethysmography during intra-arterial infusion of phosphoramidon, an endothelin-converting enzyme inhibitor, for 60 minutes, which was followed by co-infusion with endothelin-1 for 30 minutes. Three groups were studied: healthy nonpregnant women, normal pregnant women, and women with preeclampsia. RESULTS: There was a significant increase in forearm blood flow in the nonpregnant group after phosphoramidon infusion alone (73%+/-37%; P<.05). Phosphoramidon did not change forearm blood flow in pregnant subjects. Co-infusion with endothelin-1 significantly decreased forearm blood flow in both the nonpregnant and normal pregnant women (53%+/-7% and 40%+/-11%, respectively; P<.01). No response to endothelin-1 was found among women with preeclampsia. CONCLUSION: The vascular sensitivity to endothelin-1 is not altered during normal pregnancy in contrast to preeclamptic pregnancy, where no effect of endothelin-1 was seen. Reduced endothelin dependence during pregnancy might be one mechanism behind the fall in peripheral vascular resistance.
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Endotelina-1/metabolismo , Preeclampsia/fisiopatología , Embarazo , Sistema Vasomotor/fisiopatología , Adulto , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Estudios de Casos y Controles , Endotelina-1/farmacología , Enzimas Convertidoras de Endotelina , Femenino , Antebrazo/irrigación sanguínea , Glicopéptidos/farmacología , Humanos , Metaloendopeptidasas/antagonistas & inhibidores , Inhibidores de Proteasas/farmacología , Flujo Sanguíneo Regional/efectos de los fármacosRESUMEN
Pulmonary and renal haemodynamics and elimination of endothelin-1 (ET-1) were studied in six young smokers in response to 20 min intravenous infusion of ET-1 (4 pmol kg(-1) min(-1)) after smoking. At 20 min of ET-1 infusion fractional ET-1 extractions in the lungs and kidneys were 60 +/- 2 and 60 +/- 7%, respectively. Cardiac output and renal blood flow (RBF) fell by 18 +/- 4% (P<0.05) and 34 +/- 5% (P<0.01). Mean systemic arterial pressure increased (P<0.05) whereas pulmonary pressures were unchanged. Compared with previously published data in non-smokers (Weitzberg et al., 1991, 1993) basal arterial ET-1 and ET-1-values during ET-1 infusion were lower with a more rapid return to basal value. Smokers had higher pulmonary extraction of ET-1 at the same pulmonary arterial concentration (P<0.05). RBF reduction was more pronounced (P<0.05). Systemic vascular resistance increased while pulmonary vascular resistance did not increase as in non-smokers. Increased plasma clearance and more efficient pulmonary elimination of ET-1 lowers the arterial level in young smokers. In addition ET-1 evokes more pronounced renal vasoconstriction in these individuals.
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Endotelina-1/farmacocinética , Riñón/irrigación sanguínea , Pulmón/irrigación sanguínea , Fumar/efectos adversos , Vasoconstricción/efectos de los fármacos , Adulto , Factores de Edad , Gasto Cardíaco , Endotelina-1/administración & dosificación , Hemodinámica , Humanos , Infusiones Intravenosas , Masculino , Flujo Sanguíneo RegionalRESUMEN
Great changes have taken place in the fields of occupational and environmental medicine in Sweden during the past decade. Unemployment, work stress, and indoor climate problems have become increasingly common. Chemical exposures in industry and serious work accidents have continued to decrease. State subsidies to occupational health services have been withdrawn and the legislation concerning, for example, occupational diseases has been changed in order to decrease state expenditure. Research has focused on, for instance, ergonomic and psycho-social factors, electromagnetic fields and exposures causing allergy. There is a growing awareness of the need for more emphasis on prevention, which should act in favour of both hospital-based occupational and environmental medicine and the occupational health services sector.
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Medicina Ambiental/tendencias , Medicina del Trabajo/tendencias , Educación de Postgrado en Medicina/tendencias , Medicina Ambiental/educación , Medicina Ambiental/legislación & jurisprudencia , Predicción , Medicina del Trabajo/educación , Medicina del Trabajo/legislación & jurisprudencia , Práctica Profesional , Investigación , SueciaRESUMEN
We examined the relation between shift work and occupational nitrous oxide exposure in the second trimester of pregnancy and birth weight and gestational age at delivery among the members of the Swedish Midwives Association. Eighty-four per cent of members who were registered in 1989 responded to a postal questionnaire concerning occupational exposures, including work schedule and the use of nitrous oxide, in relation to each of their pregnancies. We obtained information on births from the Swedish Medical Birth Register. We used models with allowance for dependence between births for the same woman and found that night work was associated with preterm birth (<37 weeks) [odds ratio (OR) = 5.6; 95% confidence limits (CL) = 1.9, 16.4] and to a lesser extent with low birth weight [OR = 1.9 (95% CL = 0.6, 5.8)]. Three-shift work schedule (day, evening, and night rotation) showed a possible association with preterm birth [OR = 2.3 (95% CL = 0.7, 7.3)]. Exposure to nitrous oxide use was associated with reduced birth weight (-77 gm; 95% CL = -129, -24) and an increase in the odds of infants being small for gestational age (< or = 10th percentile of weight for gestational week) (OR = 1.8; 95% CL = 1.1, 2.8).
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Peso al Nacer , Edad Gestacional , Exposición Materna/efectos adversos , Partería , Óxido Nitroso/efectos adversos , Exposición Profesional/efectos adversos , Admisión y Programación de Personal , Adulto , Intervalos de Confianza , Femenino , Fertilidad , Humanos , Modelos Logísticos , Análisis Multivariante , Oportunidad Relativa , Embarazo , Segundo Trimestre del Embarazo , SueciaRESUMEN
Increased plasma concentrations of endothelin-1 (ET-1) and big endothelin-1 (big ET-1) have been reported in patients with end-stage renal failure (ESRD). In the present study, which included hemodialysis (HD) patients with (n = 21) and without (n = 32) ischemic heart disease, the putative association between plasma levels of ET-1 and big ET-1 and ischemic heart disease and the influence of the dialysis procedure on ET concentrations was investigated. This study also examined in an additional five HD patients without cardiac disease whether intravenously infused ET-1 and big ET-1 (0.2, 1, and 4 pmol/kg per min, each dose for 20 min) preserve their vasoactive potency and whether exogenous big ET-1, which in healthy humans is converted in the kidney, is still converted to ET-1 in ESRD. HD patients with ischemic heart disease demonstrated higher plasma levels of ET-1 and big ET-1 than HD patients without this disorder, and HD reduced plasma ET-1 and big ET-1 concentrations. In HD patients, the big ET-1 infusion, resulting in a 1.5-fold increase in plasma ET-1, caused a more marked and prolonged rise in mean arterial BP than ET-1 (20% versus 13%, P = 0.0001) and a slightly smaller but more prolonged decrease in estimated splanchnic blood flow than ET-1 (37% versus 44%, P = 0.02). Furthermore, big ET-1 lowered heart rate by 9% (P = 0.01) but ET-1 did not. Plasma half-lives of ET-1 and big ET-1 were longer in HD patients than in healthy humans. Thus, ET-1 and big ET-1 preserve their vasoactive potency, and circulating big ET-1 is still converted to active ET-1 in ESRD. Consequently, the increased plasma levels of ET-1 and big ET-1 noted in HD patients, especially in patients with ischemic heart disease, might play a role in the development of uremic cardiovascular complications.
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Endotelina-1/sangre , Endotelinas/sangre , Hemodinámica/efectos de los fármacos , Precursores de Proteínas/sangre , Diálisis Renal/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Endotelina-1/farmacología , Endotelinas/farmacología , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/sangre , Concentración Osmolar , Precursores de Proteínas/farmacología , Valores de Referencia , Circulación Esplácnica/efectos de los fármacos , Circulación Esplácnica/fisiología , Factores de TiempoRESUMEN
Vascular endothelin-receptor stimulation results in vasoconstriction and concomitant production of the vasodilators prostaglandin I2 and nitric oxide. The vascular effects of cyclooxygenase (COx) blockade (diclofenac intravenously) and the subsequent vasoconstrictor response to endothelin-1 (ET-1) infusion 30 min after diclofenac were studied in healthy men. With COx blockade, cardiac output (7%) and splanchnic (14%) and renal (12%) blood flows fell (all P < 0.001). Splanchnic blood flow returned to basal value within 30 min. Mean arterial blood pressure increased (4%, P < 0.001). Splanchnic glucose output fell (22%, P < 0.01). Subsequent ET-1 infusion caused, compared with previous ET-1 infusion without COx blockade (G. Ahlborg, E. Weitzberg, and J. M. Lundberg. J. Appl. Physiol. 77: 121-126, 1994; E. Weitzberg, G. Ahlborg, and J. M. Lundberg. Biochem. Biophys. Res. Commun. 180: 1298-1303, 1991; E. Weitzberg, G. Ahlborg, and J. M. Lundberg. Clin. Physiol. (Colch.) 13: 653-662, 1993), the same increase in mean arterial blood pressure (4%), decreases in cardiac output (13%) and splanchnic blood flow (38%), but no significant change in splanchnic glucose output. Renal blood flow reduction was potentiated (33 +/- 3 vs. 23 +/- 2%, P < 0.02), with a total reduction corresponding to 43 +/- 3% (P < 0.01 vs. 23 +/- 3%). We conclude that COx inhibition induces renal and splanchnic vasoconstriction. The selectively increased renal vascular responsiveness to ET-1 emphasizes the importance of endogenous arachidonic acid metabolites (i.e., prostaglandin I2) to counteract ET-1-mediated renal vasoconstriction.
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Inhibidores de la Ciclooxigenasa/farmacología , Endotelina-1/farmacología , Circulación Renal/efectos de los fármacos , Adulto , Glucemia/metabolismo , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Gasto Cardíaco/efectos de los fármacos , Diclofenaco/farmacología , Endotelina-1/sangre , Glucagón/sangre , Frecuencia Cardíaca/efectos de los fármacos , Frecuencia Cardíaca/fisiología , Humanos , Insulina/sangre , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Masculino , Consumo de Oxígeno/efectos de los fármacos , Circulación Esplácnica/efectos de los fármacos , Resistencia Vascular/efectos de los fármacosRESUMEN
We have previously demonstrated that the brain contains about 80% of the 24S-hydroxycholesterol in the human body and that there is a net flux of this steroid from the brain into the circulation (Lütjohann, D. et al. 1996. Proc. Natl. Acad. Sci. USA. 93: 9799-9804). Combining previous data with new data on 12 healthy volunteers, the arteriovenous difference between levels of this oxysterol in the internal jugular vein and in a peripheral artery was found to be -10.2 +/- 2.8 ng/ml (mean +/- SEM) corresponding to a net flux of 24S-hydroxycholesterol from the brain of about 6.4 mg/24 h. The arteriovenous difference between levels of 24S-hydroxycholesterol in the hepatic vein and a peripheral artery of 12 other volunteers was found to be 7.4 +/- 2.2 ng/ml, corresponding to a hepatic uptake of about 7.6 mg/24 h. The concentrations of 24S-hydroxycholesterol in the renal vein were about the same as those in a peripheral artery, indicating that a renal elimination is not of importance. Intravenously injected deuterium-labeled racemic 24-hydroxycholesterol was eliminated from the circulation of two human volunteers with half-lives of 10 h and 14 h, respectively. A positive correlation was found between the levels of circulating cholesterol and 24S-hydroxycholesterol. The results are consistent with a cerebral origin of most of the circulating 24S-hydroxycholesterol and suggest that the liver is the major eliminating organ. It is concluded that conversion into 24S-hydroxycholesterol is a quantitatively important mechanism for elimination of cholesterol from human brain. The possibility is discussed that circulating levels of 24S-hydroxycholesterol can be used as a marker for pathological and/or developmental changes in the brain.
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Encéfalo/metabolismo , Colesterol/metabolismo , Hidroxicolesteroles/sangre , Hidroxicolesteroles/metabolismo , Adulto , Biomarcadores , Colesterol/sangre , Deuterio , Semivida , Homeostasis , Humanos , Riñón/metabolismo , Cinética , Hígado/metabolismo , Masculino , Valores de Referencia , Circulación Esplácnica , Esteroide Hidroxilasas/metabolismoRESUMEN
The aim was to study the cardiovascular effects of the C-terminal (22-38) fragment of big endothelin-1, which is produced by the cleavage of big endothelin-1 (big ET-1) to endothelin-1 (ET-1). An intravenous infusion of the (22-38) fragment (4, 8 and 12 pmol kg-1 min-1, each dose for 10 min) was given to 10 healthy subjects. Four control subjects received 0.9% saline. Two additional subjects received ET-1 1 (0.2 and 4 pmol kg-1 min-1, each dose for 20 min) alone or combined with an equimolar infusion of the (22-38) fragment on two separate occasions. The fragment infusion did not alter heart rate, mean arterial blood pressure, cardiac output, systemic or pulmonary vascular resistance, splanchnic, cerebral or forearm blood flow. Renal blood flow showed a slight fall (11%, P < 0.001) in the fragment group of the same magnitude as in a previous control study. After the fragment infusion, a decrease in mean pulmonary arterial pressure (MPAP) by 12% (P < 0.01) and in pulmonary capillary wedge pressure (PCWP) by 31% (P < 0.001) was noted, which did not differ from the pulmonary pressures in the saline-infused control group. The (22-38) fragment, when combined with ET-1, was not able to modify the effects of ET-1 on heart rate, mean arterial blood pressure, splanchnic and renal blood flow. Consequently, the exogenous (22-38) fragment does not seem to cause any significant cardiovascular effects in healthy humans.
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Endotelinas/farmacología , Hemodinámica/efectos de los fármacos , Precursores de Proteínas/farmacología , Adulto , Presión Sanguínea/efectos de los fármacos , Catecolaminas/sangre , Circulación Cerebrovascular/efectos de los fármacos , Sinergismo Farmacológico , Endotelina-1 , Humanos , Masculino , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Circulación Pulmonar/efectos de los fármacos , Circulación Renal/efectos de los fármacos , Circulación Esplácnica/efectos de los fármacos , Factores de TiempoRESUMEN
In states of insulin resistance, increased plasma levels of endothelin-1 and a disturbed vascular reactivity have been reported. In order to investigate the effects of endothelin-1 on peripheral insulin sensitivity and the vasoactive interactions between insulin and endothelin-1, six healthy subjects were studied on two different occasions with the euglycaemic hyperinsulinaemic clamp technique combined with an intravenous infusion of either endothelin-1 (4 pmol kg-1 min-1) or 0.9% sodium chloride. During the endothelin-1 infusion, arterial plasma endothelin-1 levels rose 10-fold. The endothelin-1 infusion reduced insulin sensitivity as demonstrated by a 31 +/- 7% decrease in whole-body glucose uptake (P < 0.05) and a 26 +/- 11% fall in leg glucose uptake (P < 0.05) compared with the control protocol. During the state of hyperinsulinaemia, exogenous endothelin-1 increased mean arterial blood pressure by 8 +/- 1% (P < 0.05) and decreased splanchnic and renal blood flow by 30 +/- 6% (P < 0.001) and 20 +/- 4% (P < 0.001), respectively. However, the endothelin-1 infusion did not lower skeletal muscle blood flow measured as leg and forearm blood flow. In summary, exogenous endothelin-1 induced insulin resistance in healthy humans by reducing insulin-dependent glucose uptake in skeletal muscle without decreasing skeletal muscle blood flow. Furthermore, endothelin-1 also preserved its vasoactive potency in the presence of hyperinsulinaemia.
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Endotelina-1/farmacología , Resistencia a la Insulina/fisiología , Adulto , Glucemia/metabolismo , Electrólitos/sangre , Endotelina-1/administración & dosificación , Endotelina-1/sangre , Glucosa/metabolismo , Técnica de Clampeo de la Glucosa , Hemodinámica/efectos de los fármacos , Humanos , Infusiones Intravenosas , Insulina/sangre , Circulación Hepática/efectos de los fármacos , Circulación Hepática/fisiología , Pruebas de Función Hepática , MasculinoRESUMEN
PURPOSE: Two different methods of rigid fixation were compared for postoperative stability 6 months after mandibular advancement for treatment of Class II malocclusion. MATERIAL AND METHODS: Sixty (30 + 30) patients from two different oral and maxillofacial units treated for a Class II malocclusion by bilateral saggital split osteotomy (BSSO), and two different methods of internal rigid fixation were prospectively investigated. Two groups (S1, n = 15; S2, n = 15) had bicortical noncompressive screws inserted in the gonial area through a transcutaneous approach, and the other two groups (P1, n = 15; P2, n = 15) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively and 6 months after the operation. A computer program was used to superimpose the three cephalograms and to register the mandibular advancement and postoperative change both sagittally and vertically. RESULTS: These were minor differences in the advancement and postoperative changes between the four groups, but statistically no significant difference was shown in either sagittal or vertical directions. However, statistically verified differences proved that increasing age was associated with a smaller amount of postsurgical relapse. Low-angle cases (ML/NSL < 25 degrees) had a bigger amount of surgical (P = .0008) and postsurgical (P = .0195) movement compared with the patients in the high-angle group (ML/NSL < 38 degrees). Using a multiple regression test, a positive correlation was also shown between the amount of surgical advancement and the amount of postsurgical instability (P = .018). CONCLUSIONS: This prospective dual-center study indicates that the two different methods of internal rigid fixation after surgical advancement of the mandible by BSSO did not significantly differ from each other, and it is up to the individual operator to choose the method for internal rigid fixation.
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Técnicas de Fijación de Maxilares , Maloclusión Clase II de Angle/cirugía , Avance Mandibular/métodos , Adolescente , Adulto , Placas Óseas , Tornillos Óseos , Cefalometría , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Evaluación de Procesos y Resultados en Atención de Salud , Estudios Prospectivos , Recurrencia , Reproducibilidad de los ResultadosRESUMEN
Healthy men received NG-monomethyl-L-arginine (L-NMMA) intravenously to study cardiovascular and metabolic effects of nitric oxide synthase blockade and whether this alters the response to endothelin-1 (ET-1) infusion. Controls only received ET-1. L-NMMA effects were that heart rate (17%) cardiac output (17%), and splanchnic and renal blood flow (both 33%) fell promptly (all P < 0.01). Mean arterial blood pressure (6%), and systemic (28%) and pulmonary (40%) vascular resistance increased (P < 0.05 to 0.001). Arterial ET-1 levels (21%) increased due to a pulmonary net ET-1 release (P < 0.05 to 0.01). Splanchnic glucose output (SGO) fell (26%, P < 0.01). Arterial insulin and glucagon were unchanged. Subsequent ET-1 infusion caused no change in mean arterial pressure, heart rate, or cardiac output, as found in the present controls, or in splanchnic and renal blood flow or splanchnic glucose output as previously found with ET-1 (G. Ahlborg, E. Weitzberg, and J. M. Lundberg. J. Appl. Physiol. 79: 141-145, 1995). In conclusion, L-NMMA like ET-1, induces prolonged cardiovascular effects and suppresses SGO. L-NMMA causes pulmonary ET-1 release and blocks responses to ET-1 infusion. The results indicate that nitric oxide inhibits ET-1 production and thereby interacts with ET-1 regarding increase in vascular tone and reduction of SGO in humans.
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Endotelina-1/sangre , Óxido Nítrico/metabolismo , Adulto , Análisis de los Gases de la Sangre , Glucemia , Presión Sanguínea/efectos de los fármacos , Gasto Cardíaco/efectos de los fármacos , Inhibidores Enzimáticos/administración & dosificación , Glucagón/sangre , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Inyecciones Intravenosas , Insulina/sangre , Masculino , Contracción Muscular/fisiología , Músculo Liso/efectos de los fármacos , Músculo Liso/enzimología , Óxido Nítrico/biosíntesis , Óxido Nítrico Sintasa/antagonistas & inhibidores , Circulación Pulmonar/efectos de los fármacos , Circulación Pulmonar/fisiología , Circulación Renal/efectos de los fármacos , Circulación Renal/fisiología , Respiración/fisiología , Circulación Esplácnica/efectos de los fármacos , Circulación Esplácnica/fisiología , Resistencia Vascular/efectos de los fármacos , omega-N-Metilarginina/administración & dosificaciónRESUMEN
The effect of intravenous administration of the endothelium derived vasoconstrictor peptide endothelin-1 (ET-1 0.2. 1 and 8 pmol kg-1 min-1) on coronary blood flow in relation to plasma ET-1 as well as blood lactate and glucose levels were investigated in six healthy volunteers. Coronary sinus blood flow was measured by thermodilution. Administration of ET-1 elevated arterial plasma ET 35-fold, dose-dependently increased mean arterial blood pressure from 95 +/- 5 mmHg to 110 +/- 6 mmHg (P < 0.01) and reduced heart rate from 64 +/- 4 beats min-1 to 58 +/- 4 beats min-1 (P < 0.05) at 8 pmol kg-1 min-1. Coronary sinus blood flow was reduced maximally by 23 +/- 4% (P < 0.01) and coronary vascular resistance increased by 48 +/- 11% (P < 0.01). Coronary sinus oxygen saturation decreased from 35 +/- 1% to 22 +/- 2% at 2 min after the infusion (P < 0.01). A coronary constrictor response was observed at a 4-fold elevation in plasma ET. The reduction is coronary sinus blood flow lasted 20 min and coronary sinus oxygen saturation was still reduced 60 min after the infusion. Myocardial oxygen uptake or arterial oxygen saturation were not affected by ET-1. Myocardial lactate net uptake decreased by 40% whereas glucose uptake was unaffected. At the highest infusion rate there was a net removal of plasma ET by 24 +/- 3% over the myocardium (P < 0.05). The results show that ET-1 induces long-lasting reduction in coronary sinus blood flow via a direct coronary vasoconstrictor effect in healthy humans observable at a 4-fold elevation in plasma ET-1. Furthermore, there is a net removal of circulating ET-1 by the myocardium.
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Circulación Coronaria/efectos de los fármacos , Endotelina-1/farmacología , Endotelina-1/farmacocinética , Miocardio/metabolismo , Vasoconstrictores/farmacología , Adulto , Glucemia/análisis , Endotelina-1/sangre , Hemodinámica/efectos de los fármacos , Humanos , Ácido Láctico/sangre , Masculino , Factores de TiempoRESUMEN
BACKGROUND: Endothelin-1 (ET-1) is a potent vasoconstrictor produced from the precursor big ET-1 in endothelial cells. The coronary effects of these peptides in humans in vivo are unknown. Therefore, the effects of ET-1 and big ET-1 on coronary blood flow in relation to plasma ET-1 and big ET-1 levels were compared in healthy subjects. METHODS AND RESULTS: The peptides were infused intravenously at the rates of 0.2, 1, and 8 pmol/kg per minute. Each dose administered for 20 minutes except the highest dose of ET-1, which was administered for 10 minutes. ET-1 and big ET-1 evoked dose-related increases in mean arterial blood pressure from 93 +/- 4 to 107 +/- 4 mm Hg and from 89 +/- 2 to 122 +/- 5 mm Hg, respectively, at the highest dose. ET-1 and big ET-1 reduced coronary sinus blood flow, measured with thermodilution by a maximum of 25 +/- 4% and 28 +/- 8% and increased coronary vascular resistance by 50 +/- 9% and 107 +/- 26%, respectively. Coronary sinus, but not arterial, oxygen saturation was reduced in parallel with the coronary sinus blood flow. The effects of ET-1 and big ET-1 were similar at corresponding time points. During infusion of ET-1, a 19 +/- 5% extraction of ET-1 was observed over the coronary vascular bed (P < .05). Administration of big ET-1 elevated arterial plasma ET-1 levels by 2.4-fold, and after correction for the local extraction of ET-1, a myocardial production of ET-1 was observed. CONCLUSIONS: ET-1 and big ET-1 induce comparable increases in blood pressure and coronary constriction in humans in vivo. The results also suggest a net local removal of circulating ET-1 and big ET-1 and a local conversion of big ET-1 into ET-1 within the coronary vascular bed.
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Vasos Coronarios/efectos de los fármacos , Endotelina-1/farmacología , Endotelinas/farmacología , Precursores de Proteínas/farmacología , Vasoconstricción/efectos de los fármacos , Adulto , Circulación Coronaria/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Endotelina-1/biosíntesis , Endotelina-1/sangre , Endotelinas/sangre , Endotelinas/metabolismo , Hemodinámica/efectos de los fármacos , Humanos , Masculino , Precursores de Proteínas/sangre , Precursores de Proteínas/metabolismoRESUMEN
In search of early signs of autonomic and vascular dysfunction in diabetic subjects, six young men with type I diabetes and six healthy subjects were investigated regarding arterial levels of noradrenaline (NA), neuropeptide Y- (NPY) and endothelin-1-(ET-1) like immunoreactivity (Li) during and after 1 h of exercise at 70% of peak oxygen uptake. Basal NA, NPY-Li and ET-1-Li levels did not differ between groups. NA and NPY-Li rose during exercise in diabetic subjects to only 60% of the control values (P < 0.05, interaction group x time P < 0.001). Disappearance rates for NA and NPY-Li did not differ between groups. Plasma ET-1-Li did not differ between groups during exercise. Values returned to basal levels within 5 min in the diabetic but not in the control group. In conclusion, diabetic subjects show lower NPY-Li and NA levels than control subjects during exercise but similar disappearance rates after exercise, indicating lower releases. Furthermore, plasma ET-1 levels did not differ between groups during exercise.
Asunto(s)
Diabetes Mellitus Tipo 1/sangre , Endotelina-1/sangre , Ejercicio Físico/fisiología , Neuropéptido Y/sangre , Norepinefrina/sangre , Adulto , Glucemia/metabolismo , Diabetes Mellitus Tipo 1/fisiopatología , Metabolismo Energético/fisiología , Prueba de Esfuerzo , Glicerol/sangre , Frecuencia Cardíaca/fisiología , Humanos , Ácido Láctico/sangre , Masculino , Posición Supina/fisiologíaRESUMEN
We have investigated whether side chain-hydroxylated cholesterol species are important for elimination of cholesterol from the brain. Plasma concentrations of 24-hydroxycholesterol (24-OH-Chol) in the internal jugular vein and the brachial artery in healthy volunteers were consistent with a net flux of this steroid from the brain into the circulation, corresponding to elimination of approximately 4 mg cholesterol during a 24-h period in adults. Results of experiments with rats exposed to 18O2 were also consistent with a flux of 24-OH-Chol from the brain into the circulation. No other oxysterol measured showed a similar behavior as 24-OH-Chol. These results and the finding that the concentration of 24-OH-Chol was 30- to 1500-fold higher in the brain than in any other organ except the adrenals indicate that the major part of 24-OH-Chol present in the circulation originates from the brain. Both the 24-OH-Chol present in the brain and in the circulation were the 24S-stereoisomer. In contrast to other oxysterols, levels of plasma 24-OH-Chol were found to be markedly dependent upon age. The ratio between 24-OH-Chol and cholesterol in plasma was approximately 5 times higher during the first decade of life than during the sixth decade. There was a high correlation between levels of 24-OH-Chol in plasma and cerebrospinal fluid. It is suggested that the flux of 24-OH-Chol from the brain is important for cholesterol homeostasis in this organ.