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1.
BMC Psychiatry ; 22(1): 400, 2022 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-35705927

RESUMEN

BACKGROUND: Financial distress is thought to be a key reason why small-medium enterprise (SME) owners experience higher levels of mental health conditions compared with the broader population. Business advisors who form trusting, high-quality relationships with their SME clients, are therefore well placed to: (1) help prevent/reduce key sources of financial distress, (2) better understand the business and personal needs of their clients and, (3) recognise the signs and symptoms of mental health conditions and encourage help-seeking where appropriate. The aim of this study is to compare the effectiveness of relationship building training (RBT) combined with mental health first aid (MHFA) training for business advisors with MHFA alone, on the financial and mental health of their SME-owner clients. METHODS: This is a single blind, two-arm randomised controlled trial. Participants will be business advisors who provide information, guidance and/or assistance to SME owner clients and are in contact with them at least 3 times a year. The business advisors will invite their SME-owner clients to complete 3 online surveys at baseline, 6- and 12-months. Business advisors will be randomised to one of two conditions, using a 1:1 allocation ratio: (1) MHFA with RBT; or (2) MHFA alone, and complete 3 online surveys at baseline, 2- and 6-months. Primary outcomes will be measured in the business advisors and consist of the quality of the relationship, stigmatizing attitude, confidence to offer mental health first aid, quality of life and provision of mental health first aid. Secondary outcomes will be measured in the SME owners and includes trust in their business advisors, the quality of this relationship, financial wellbeing, financial distress, psychological distress, help-seeking behaviour, and quality of life. To complement the quantitative data, we will include a qualitative process evaluation to examine what contextual factors impacted the reach, effectiveness, adoption, implementation, and maintenance of the training. DISCUSSION: As there is evidence for the connections between client trust, quality of relationship and financial and mental wellbeing, we hypothesise that the combined RBT and MHFA training will lead to greater improvements in these outcomes in SME owners compared with MHFA alone. TRIAL REGISTRATION: ClinicalTrials.gov : NCT04982094 . Retrospectively registered 29/07/2021. The study started in February 2021 and the recruitment is ongoing.


Asunto(s)
Alfabetización en Salud , Salud Mental , Humanos , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Método Simple Ciego , Confianza
2.
Epidemiol Psychiatr Sci ; 26(3): 276-286, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-26804972

RESUMEN

AIMS: Adults who experienced the 1992 and 2008 armed conflicts in the Republic of Georgia were exposed to multiple traumatic events and stressors over many years. The aim was to investigate what coping strategies are used by conflict-affected persons in Georgia and their association with mental disorders. METHOD: A cross-sectional survey was conducted with 3600 adults, representing internally displaced persons (IDPs) from conflicts in the 1990s (n = 1200) and 2008 (n = 1200) and former IDPs who returned to their homes after the 2008 conflict (n = 1200). Post-traumatic stress disorder, depression, anxiety and coping strategies were measured using the Trauma Screening Questionnaire, Patient Health Questionnaire-9, Generalised Anxiety and adapted version of the Brief Coping Inventory, respectively. Descriptive and multivariate regression analyses were used. RESULTS: Coping strategies such as use of humour, emotional support, active coping, acceptance and religion were significantly associated with better mental health outcomes. Coping strategies of behavioural and mental disengagement, denial, venting emotions, substance abuse and gambling were significantly associated with poorer mental health outcomes. The reported use of coping strategies varied significantly between men and women for 8 of the 15 strategies addressed. CONCLUSIONS: Many conflict-affected persons in Georgia are still suffering mental health problems years after the conflicts. A number of specific coping strategies appear to be associated with better mental health and should be encouraged and supported where possible.


Asunto(s)
Adaptación Psicológica , Trastornos Relacionados con Alcohol/psicología , Conflictos Armados/psicología , Trastornos Mentales/psicología , Salud Mental , Trastornos por Estrés Postraumático/psicología , Trastornos de Estrés Traumático/psicología , Adulto , Trastornos Relacionados con Alcohol/epidemiología , Ansiedad/epidemiología , Ansiedad/etiología , Estudios Transversales , Femenino , Georgia (República)/epidemiología , Humanos , Trastornos de Estrés Traumático/epidemiología , Encuestas y Cuestionarios , Adulto Joven
3.
Osteoarthritis Cartilage ; 23(6): 940-8, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25655679

RESUMEN

OBJECTIVES: Changes in subchondral bone (SCB) and cross-talk with articular cartilage (AC) have been linked to osteoarthritis (OA). Using micro-computed tomography (micro-CT) this study: (1) examines changes in SCB architecture in a non-invasive loading mouse model in which focal AC lesions are induced selectively in the lateral femur, and (2) determines any modifications in the contralateral knee, linked to changes in gait, which might complicate use of this limb as an internal control. METHODS: Right knee joints of CBA mice were loaded: once with 2 weeks of habitual use (n = 7), for 2 weeks (n = 8) or for 5 weeks (n = 5). Both left (contralateral) and right (loaded) knees were micro-CT scanned and the SCB and trabecular bone analysed. Gait analysis was also performed. RESULTS: These analyses showed a significant increase in SCB thickness in the lateral compartments in joints loaded for 5 weeks, which was most marked in the lateral femur; the contralateral non-loaded knee also showed transient SCB thickening (loaded once and repetitively). Epiphyseal trabecular bone BV/TV and trabecular thickness were also increased in the lateral compartments after 5 weeks of loading, and in all joint compartments in the contralateral knee. Gait analysis showed that applied loading only affected gait in the contralateral himd-limb in all groups of mice from the second week after the first loading episode. CONCLUSIONS: These data indicate a spatial link between SCB thickening and AC lesions following mechanical trauma, and the clear limitations associated with the use of contralateral joints as controls in such OA models, and perhaps in OA diagnosis.


Asunto(s)
Artritis Experimental/patología , Cartílago Articular/lesiones , Fémur/patología , Osteoartritis/patología , Tibia/patología , Animales , Artritis Experimental/etiología , Artritis Experimental/fisiopatología , Epífisis/patología , Fémur/fisiopatología , Marcha/fisiología , Masculino , Ratones Endogámicos CBA , Actividad Motora/fisiología , Osteoartritis/etiología , Osteoartritis/fisiopatología , Estrés Mecánico , Tibia/fisiopatología , Soporte de Peso/fisiología , Microtomografía por Rayos X
4.
Endocrinology ; 153(5): 2254-66, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22416084

RESUMEN

To determine the effect of estrogen receptors (ER) α and ß on bones' adaptive response to loading, we subjected the right tibiae of mice lacking ERα or ERß activity to either axial loading or to disuse. Adaptive changes in architecture were assessed by comparing differences between the right (treated) and left (control) tibiae in these genotypes as assessed by microcomputed tomography. In female ERα(-/-) mice, the net-osteogenic response to loading was lower in cortical bone compared with their wild-type littermates (11.2 vs. 20.9% in ERα(+/+)), but it was higher in both cortical and cancellous bone of male ERα(-/-) mice (cortical 20.0 vs. 4.6% in ERα(+/+); cancellous 30.0 vs. 5.3% in ERα(+/+), P < 0.05). In ERß(-/-) male and female mice, the net-osteogenic response to loading was higher in cortical bone (males 10.9 vs. 3.9% in ERß(+/+); females 18.5 vs. 15.8% in ERß(+/+), P < 0.05) but no different from controls in cancellous bone. The bone loss in response to disuse was less in cancellous bone of ERα(-/-) mice than in controls (-15.9 vs. -21.3%, respectively, P < 0.05) but no different at any other site or between any other groups. Our conclusion is that functional ERα enhances the net-osteogenic response to loading in cortical but not cancellous bone in female mice but reduces it in males. ERß decreases the response to loading in cortical bone of males and females but has no effect in cancellous bone. Bone loss due to disuse in cortical bone is unaffected by ER status, but in cancellous bone, functional ERα contributes to greater disuse-related bone loss.


Asunto(s)
Adaptación Fisiológica/fisiología , Receptor alfa de Estrógeno/metabolismo , Receptor beta de Estrógeno/metabolismo , Tibia/fisiología , Animales , Peso Corporal/fisiología , Receptor alfa de Estrógeno/genética , Receptor beta de Estrógeno/genética , Femenino , Masculino , Ratones , Ratones Noqueados , Factores Sexuales , Estrés Mecánico , Tibia/metabolismo , Soporte de Peso/fisiología
5.
Pharmacol Biochem Behav ; 96(2): 148-51, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20451546

RESUMEN

Benzodiazepine withdrawal has been associated with hostile and aggressive behavior. The benzodiazepine antagonist flumazenil has reduced, increased or not affected hostility and aggression in animal and human studies. In the present study we analyzed data collected in a placebo-controlled study of the effects of the benzodiazepine antagonist flumazenil in patients previously treated for benzodiazepine dependency, and healthy controls. The aim was to analyze the effects of flumazenil on hostility and aggression. Ten patients and 10 controls received, on two separate occasions, cumulative doses of flumazenil (0.05, 0.1, 0.25, 0.5 and 1mg at 15min intervals) or placebo. Withdrawal symptoms were rated after each injection. Patients had been free from benzodiazepines for 47 (4-266) weeks on the first occasion. A three-way interaction (groupxtreatmentxdose) was found, and was explained by: 1) patients rating aggression and hostility higher than controls at all times during placebo, while 2) during the flumazenil provocation i) the initial significant difference between patients and controls was no longer significant above the 0.5mg dose, and ii) patients rated aggression and hostility significantly lower above the 0.5mg dose compared to base-line. The results suggest that self-rated aggression and hostility in patients treated for benzodiazepine dependency was reduced by the partial benzodiazepine agonist flumazenil.


Asunto(s)
Agresión/efectos de los fármacos , Benzodiazepinas/efectos adversos , Flumazenil/farmacología , Síndrome de Abstinencia a Sustancias/tratamiento farmacológico , Síndrome de Abstinencia a Sustancias/psicología , Trastornos Relacionados con Sustancias/psicología , Adulto , Relación Dosis-Respuesta a Droga , Femenino , Flumazenil/administración & dosificación , Hostilidad , Humanos , Masculino , Persona de Mediana Edad
6.
Bone ; 47(2): 309-19, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20399918

RESUMEN

Adenosine 5'-monophosphate-activated protein kinase (AMPK), a regulator of energy homeostasis, has a central role in mediating the appetite-modulating and metabolic effects of many hormones and antidiabetic drugs metformin and glitazones. The objective of this study was to determine if AMPK can be activated in osteoblasts by known AMPK modulators and if AMPK activity is involved in osteoblast function in vitro and regulation of bone mass in vivo. ROS 17/2.8 rat osteoblast-like cells were cultured in the presence of AMPK activators (AICAR and metformin), AMPK inhibitor (compound C), the gastric peptide hormone ghrelin and the beta-adrenergic blocker propranolol. AMPK activity was measured in cell lysates by a functional kinase assay and AMPK protein phosphorylation was studied by Western Blotting using an antibody recognizing AMPK Thr-172 residue. We demonstrated that treatment of ROS 17/2.8 cells with AICAR and metformin stimulates Thr-172 phosphorylation of AMPK and dose-dependently increases its activity. In contrast, treatment of ROS 17/2.8 cells with compound C inhibited AMPK phosphorylation. Ghrelin and propranolol dose-dependently increased AMPK phosphorylation and activity. Cell proliferation and alkaline phosphatase activity were not affected by metformin treatment while AICAR significantly inhibited ROS 17/2.8 cell proliferation and alkaline phosphatase activity at high concentrations. To study the effect of AMPK activation on bone formation in vitro, primary osteoblasts obtained from rat calvaria were cultured for 14-17days in the presence of AICAR, metformin and compound C. Formation of 'trabecular-shaped' bone nodules was evaluated following alizarin red staining. We demonstrated that both AICAR and metformin dose-dependently increase trabecular bone nodule formation, while compound C inhibits bone formation. When primary osteoblasts were co-treated with AICAR and compound C, compound C suppressed the stimulatory effect of AICAR on bone nodule formation. AMPK is a alphabetagamma heterotrimer, where alpha is the catalytic subunit. RT-PCR analysis of AMPK subunits in ROS17/2.8 osteoblastic cells and in mouse tibia showed that the AMPKalpha1 subunit is the dominant isoform expressed in bone. We analysed the bone phenotype of 4month-old male wild type (WT) and AMPKalpha1-/- KO mice using micro-CT. Both cortical and trabecular bone compartments were smaller in the AMPK alpha1-deficient mice compared to the WT mice. Altogether, our data support a role for AMPK signalling in skeletal physiology.


Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Huesos/citología , Huesos/enzimología , Osteogénesis/fisiología , Proteínas Quinasas Activadas por AMP/deficiencia , Proteínas Quinasas Activadas por AMP/genética , Fosfatasa Alcalina/metabolismo , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacología , Animales , Huesos/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Activadores de Enzimas/farmacología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Metformina/farmacología , Ratones , Ratones Noqueados , Sistemas Neurosecretores/enzimología , Tamaño de los Órganos/efectos de los fármacos , Osteoblastos/citología , Osteoblastos/efectos de los fármacos , Osteoblastos/enzimología , Osteogénesis/efectos de los fármacos , Fenotipo , Subunidades de Proteína/deficiencia , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ribonucleótidos/farmacología , Tibia/efectos de los fármacos , Tibia/enzimología
7.
Am J Physiol Endocrinol Metab ; 293(2): E484-91, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17535856

RESUMEN

Mechanical loading caused by physical activity can stimulate bone formation and strengthen the skeleton. Estrogen receptors (ERs) play some role in the signaling cascade that is initiated in bone cells after a mechanical load is applied. We hypothesized that one of the ERs, ER-beta, influences the responsiveness of bone to mechanical loads. To test our hypothesis, 16-wk-old male and female mice with null mutations in ER-beta (ER-beta(-/-)) had their right forelimbs subjected to short daily loading bouts. The loading technique used has been shown to increase bone formation in the ulna. Each loading bout consisted of 60 compressive loads within 30 s applied daily for 3 consecutive days. Bone formation was measured by first giving standard fluorochrome bone labels 1 and 6 days after loading and using quantitative histomorphometry to assess bone sections from the midshaft of the ulna. The left nonloaded ulna served as an internal control for the effects of loading. Mechanical loading increased bone formation rate at the periosteal bone surface of the mid-ulna in both ER-beta(-/-) and wild-type (WT) mice. The ulnar responsiveness to loading was similar in male ER-beta(-/-) vs. WT mice, but for female mice bone formation was stimulated more effectively in ER-beta(-/-) mice (P < 0.001). We conclude that estrogen signaling through ER-beta suppresses the mechanical loading response on the periosteal surface of long bones.


Asunto(s)
Huesos/fisiología , Codón sin Sentido , Receptor beta de Estrógeno/genética , Estrés Mecánico , Soporte de Peso , Animales , Densidad Ósea , Estrógenos/fisiología , Femenino , Masculino , Mecanotransducción Celular/genética , Ratones , Ratones Noqueados , Modelos Biológicos , Cúbito/fisiología
8.
J Nutr Health Aging ; 10(2): 151-3, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16554952

RESUMEN

BACKGROUND: Seasonal Affective Disorder (SAD) is a sub-type of depression that only occurs during the winter months. A reduction in vitamin D may be linked to SAD. Since vitamin D deficiency has been reported to be common in older people, vitamin D supplementation may be expected to reduce seasonal mood disturbance in this group. OBJECTIVE: To assess the effect of vitamin D supplementation on the mental health of older women. SETTING: Primary care in three areas of the UK (Herts, Newcastle, York). SUBJECTS: Women aged 70 years or more recruited to the trial in the months May-October. INTERVENTION: Eligible women were randomised to receive calcium and vitamin D supplementation or no supplementation. OUTCOME MEASURE: At baseline and the six monthly assessment the mental component score (MCS), calculated from the SF-12 questionnaire was used to assess participants' subjective psychological well-being. RESULTS: A total of 2117 women recruited to the trial had their baseline measures taken between the months of May-October (1205 woman in the control group and 912 women in the intervention group). Of these women, 1621 had a MCS score at baseline and six months. Comparison of the six month mean MCS scores, adjusting for baseline MCS score and age, showed there was no significant difference between the two scores (p = 0.262). CONCLUSIONS: Supplementing elderly women with 800 IU of vitamin D daily did not lead to an improvement in mental health scores.


Asunto(s)
Salud Mental , Psicometría/métodos , Trastorno Afectivo Estacional/prevención & control , Vitamina D/administración & dosificación , Anciano , Calcio de la Dieta/administración & dosificación , Suplementos Dietéticos , Femenino , Humanos , Resultado del Tratamiento
9.
Bone ; 36(2): 185-92, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15780944

RESUMEN

We have known for sometime that sex hormones influence the growth, preservation, and loss of bone tissue in the skeleton. However, we are only beginning to recognize how estrogen influences the responsiveness of the skeleton to exercise. Frost's mechanostat theory proposes that estrogen reduces the mechanical strain required to initiate an osteogenic response, but this may only occur at the endocortical and trabecular bone surfaces. The discovery of estrogen receptors alpha and beta may help us to understand the bone surface-specific effects of exercise. Findings from estrogen receptor knockout mice suggest that the activity of ERalpha may explain the positive interaction between estrogen and exercise on bone formation near marrow, that is, endocortical and trabecular bone surfaces. Estrogen inhibits the anabolic exercise response at the periosteal surface, and this we propose is due to the activation of ERbeta. Signaling through this receptor retards periosteal bone formation and suppresses gains in bone size and bone strength, and for these reasons it behaves as an antimechanostat.


Asunto(s)
Fenómenos Biomecánicos , Receptor beta de Estrógeno/fisiología , Ejercicio Físico/fisiología , Osteogénesis/fisiología , Estrés Mecánico , Animales , Fenómenos Biomecánicos/métodos , Humanos , Transducción de Señal/fisiología
10.
Bone ; 36(3): 454-64, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15777679

RESUMEN

After the initial adaptation to large mechanical loads, it appears as though the skeleton's responsiveness to exercise begins to wane. To counteract the waning effects of long-term mechanical loading, "time off" may be needed to improve the responsiveness of bone cells to future mechanical signals and reinitiate bone formation. The aim of this study was to determine whether bone becomes less sensitive to long-term mechanical loading and whether time off is needed to improve mechanosensitivity. Fifty-seven female Sprague-Dawley rats (7-8 months of age) were randomized to one of following groups: Group 1 loading was applied for 5 weeks followed by 10 weeks of time off (1 x 5); Group 2 loading was applied for 5 weeks, followed by time off for 5 weeks and loading again for 5 weeks (2 x 5); Group 3 loading was applied continuously for 15 weeks (3 x 5); Group 4 age-matched control group; and Group 5 baseline control group. An axial load was applied to the right ulna for 360 cycles/day, at 2 Hz, 3 days/week at 15 N. At the end of the intervention, all three loaded groups showed similar increases in bone mass, cortical area, and I(MIN) in response to mechanical loading(.) Bone formation rate of the loaded ulna was increased in the first 5 weeks of loading for all three loaded groups; however, during the last 5 weeks, it was only significantly increased in the group that had time off (2 x 5) (P < 0.05). The group that had time off (2 x 5) also showed greater improvements in work to failure compared to the group loaded for 5 weeks (1 x 5) and the entire 15 weeks (3 x 5). A second experiment showed that the waning effect of long-term loading on the skeleton is not a result of aging. In conclusion, mechanical loading of the rat ulna results in large improvements in bone formation during the first 5 weeks of loading, but continual loading decreases the osteogenic response. Having time off increases bone formation and improves the resistance to fracture.


Asunto(s)
Densidad Ósea/fisiología , Huesos/fisiología , Animales , Femenino , Ratas , Ratas Sprague-Dawley , Estrés Mecánico , Factores de Tiempo , Soporte de Peso/fisiología
11.
Bone ; 34(2): 281-7, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14962806

RESUMEN

As muscles become larger and stronger during growth and in response to increased loading, bones should adapt by adding mass, size, and strength. In this unilateral model, we tested the hypothesis that (1) the relationship between muscle size and bone mass and geometry (nonplaying arm) would not change during different stages of puberty and (2) exercise would not alter the relationship between muscle and bone, that is, additional loading would result in a similar unit increment in both muscle and bone mass, bone size, and bending strength during growth. We studied 47 competitive female tennis players aged 8-17 years. Total, cortical, and medullary cross-sectional areas, muscle area, and the polar second moment of area (I(p)) were calculated in the playing and nonplaying arms using magnetic resonance imaging (MRI); BMC was assessed by DXA. Growth effects: In the nonplaying arm in pre-, peri- and post-pubertal players, muscle area was linearly associated BMC, total and cortical area, and I(p) (r = 0.56-0.81, P < 0.09 to < 0.001), independent of age. No detectable differences were found between pubertal groups for the slope of the relationship between muscle and bone traits. Post-pubertal players, however, had a higher BMC and cortical area relative to muscle area (i.e., higher intercept) than pre- and peri-pubertal players (P < 0.05 to < 0.01), independent of age; pre- and peri-pubertal players had a greater medullary area relative to muscle area than post-pubertal players (P < 0.05 to < 0.01). Exercise effects: Comparison of the side-to-side differences revealed that muscle and bone traits were 6-13% greater in the playing arm in pre-pubertal players, and did not increase with advancing maturation. In all players, the percent (and absolute) side-to-side differences in muscle area were positively correlated with the percent (and absolute) differences in BMC, total and cortical area, and I(p) (r = 0.36-0.40, P < 0.05 to < 0.001). However, the side-to-side differences in muscle area only accounted for 11.8-15.9% of the variance of the differences in bone mass, bone size, and bending strength. This suggests that other factors associated with loading distinct from muscle size itself contributed to the bones adaptive response during growth. Therefore, the unifying hypothesis that larger muscles induced by exercise led to a proportional increase in bone mass, bone size, and bending strength appears to be simplistic and denies the influence of other factors in the development of bone mass and bone shape.


Asunto(s)
Huesos/anatomía & histología , Huesos/fisiología , Ejercicio Físico/fisiología , Músculo Esquelético/anatomía & histología , Músculo Esquelético/crecimiento & desarrollo , Adolescente , Niño , Femenino , Lateralidad Funcional , Humanos , Recién Nacido , Imagen por Resonancia Magnética , Pubertad/fisiología , Tenis
12.
J Bone Miner Res ; 17(12): 2274-80, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12469922

RESUMEN

Exercise during growth results in biologically important increases in bone mineral content (BMC). The aim of this study was to determine whether the effects of loading were site specific and depended on the maturational stage of the region. BMC and humeral dimensions were determined using DXA and magnetic resonance imaging (MRI) of the loaded and nonloaded arms in 47 competitive female tennis players aged 8-17 years. Periosteal (external) cross-sectional area (CSA), cortical area, medullary area, and the polar second moments of area (I(P), mm4) were calculated at the mid and distal sites in the loaded and nonloaded arms. BMC and I(P) of the humerus were 11-14% greater in the loaded arm than in the nonloaded arm in prepubertal players and did not increase further in peri- or postpubertal players despite longer duration of loading (both, p < 0.01). The higher BMC was the result of a 7-11% greater cortical area in the prepubertal players due to greater periosteal than medullary expansion at the midhumerus and a greater periosteal expansion alone at the distal humerus. Loading late in puberty resulted in medullary contraction. Growth and the effects of loading are region and surface specific, with periosteal apposition before puberty accounting for the increase in the bone's resistance to torsion and endocortical contraction contributing late in puberty conferring little increase in resistance to torsion. Increasing the bone's resistance to torsion is achieved by modifying bone shape and mass, not necessarily bone density.


Asunto(s)
Fenómenos Biomecánicos , Huesos/anatomía & histología , Pubertad , Tenis , Adolescente , Niño , Femenino , Humanos
14.
Circulation ; 103(25): 3092-8, 2001 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-11425774

RESUMEN

BACKGROUND: The purpose of our study was to define the incidence and mechanisms of atypical right atrial flutter. METHODS AND RESULTS: A total of 28 (8%) of 372 consecutive patients with atrial flutter (AFL) had 36 episodes of sustained atypical right AFL. Among 24 (67%) of 36 episodes of lower loop reentry (LLR), 13 (54%) of 24 episodes had early breakthrough at the lower lateral tricuspid annulus, whereas 11 (46%) of 24 episodes had early breakthrough at the high lateral tricuspid annulus, and 9 (38%) of 24 episodes showed multiple annular breaks. Bidirectional isthmus block resulted in elimination of LLR. A pattern of posterior breakthrough from the eustachian ridge to the septum was observed in 4 (14%) of 28 patients. Upper loop reentry was observed in 8 (22%) of 36 episodes and was defined as showing a clockwise orientation with early annular break and wave-front collision over the isthmus. Two patients had atypical right AFL around low voltage areas ("scars") in the posterolateral right atrium. CONCLUSIONS: Atypical right AFL is most commonly associated with an isthmus-dependent mechanism (ie, LLR or subeustachian isthmus breaks). Non-isthmus-dependent circuits include upper loop reentry or scar-related circuits.


Asunto(s)
Aleteo Atrial/fisiopatología , Atrios Cardíacos/fisiopatología , Anciano , Estudios de Cohortes , Electrocardiografía , Sistema de Conducción Cardíaco/fisiopatología , Humanos , Persona de Mediana Edad , Taquicardia/fisiopatología
15.
Psychopharmacology (Berl) ; 153(2): 231-7, 2001 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-11205424

RESUMEN

RATIONALE: Benzodiazepines have dependency-producing properties, and the majority of patients who are prescribed benzodiazepines and are treated for benzodiazepine dependency are women. Inability to cope with withdrawal symptoms may lead to continued consumption of benzodiazepines, often with the development of tolerance and dose escalation as a consequence. OBJECTIVE: In the present study we analyzed gender-related differences in reactions to placebo injections in a placebo-controlled study of the effects of the benzodiazepine antagonist flumazenil among patients previously treated for benzodiazepine dependency and healthy controls. METHODS: Ten patients and ten controls (five males and five females in each group) received two placebo injections (separated by 15 min) on two separate occasions (1-13 weeks apart). The patients had been benzodiazepine free for 47 (4-266) weeks on the first occasion. Subjective ratings of symptoms, thought to be important during/after withdrawal of benzodiazepines, were made before and after each injection, as well as registrations of blood pressure and heart rate. RESULTS: An overall difference existed between previously benzodiazepine-dependent subjects and healthy controls, with patients scoring higher on negative and somatic aggregates and lower on a positive aggregate. A four-way interaction (group x gender x occasion x time) was found for negative and somatic aggregates, which could mainly be explained by the reactions of female patients. Thus, females had the highest base-line ratings and were the only group that showed a significant reduction in symptom ratings after placebo injections on the first occasion. Gender differences were also found for systolic and diastolic blood pressure. There was no significant response to placebo among male patients or for controls (males or females) for ratings of any variable. CONCLUSIONS: The results suggest that there might be gender-specific differences in reactions to placebo injections, with female patients being more affected. Arguments for and against explanatory factors such as expectation, provider factors, habituation, regression toward the mean, and reduction of anxiety are presented.


Asunto(s)
Ansiolíticos/efectos adversos , Síndrome de Abstinencia a Sustancias/psicología , Adulto , Presión Sanguínea/efectos de los fármacos , Tolerancia a Medicamentos , Femenino , Flumazenil/farmacología , Moduladores del GABA/farmacología , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Caracteres Sexuales , Método Simple Ciego , Síndrome de Abstinencia a Sustancias/fisiopatología
16.
Alcohol ; 22(2): 69-74, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11113620

RESUMEN

Although acute tolerance (AT) to alcohol has been demonstrated in many single-dose studies, the existence of AT at steady state concentrations of alcohol has been questioned. In the present study, six subjects were examined as (1) 7.5% alcohol or (2) placebo was administered intravenously (IV). The order of the infusions was randomized. The alcohol infusions were designed to result in similar blood alcohol concentrations at 20, 60, and 140 min (approximately 0. 7 per thousand). At 20 min, the concentrations were rising; the steady state (+/-0.10 per thousand) was reached after 60 min and continued until 140 min. Three reaction time (RT) tests from the automated psychological test system were used (simple RT, two-choice RT, and two-choice RT with auditory inhibition). When the performance of the subjects was compared at rising and steady-state concentrations of alcohol, AT was shown for the most complex task requiring parallel processing, i.e., RT with failed inhibition, test. However, at steady state (i.e., 60 vs. 140 min), AT was not found for any of the tests. Further, the analysis showed that the test results of different individuals were related to their estimated normal alcohol consumption and that these differences presumably influenced the test results in accordance with our earlier findings.


Asunto(s)
Tolerancia a Medicamentos , Etanol/administración & dosificación , Adulto , Etanol/sangre , Humanos , Infusiones Intravenosas , Cinética , Masculino , Proyectos Piloto , Placebos , Tiempo de Reacción
17.
Am J Cardiol ; 86(9A): 111K-115K, 2000 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-11084109

RESUMEN

Cardiac pacing remains one of the most effective means for preventing torsade de pointes in patients with long QT syndrome (LQTS). However, fatal arrhythmias may occur despite combined therapy with beta blockers and pacing, and it is possible that failure of cardiac pacing for preventing arrhythmias in the long run is related (at least in part) to suboptimal pacemaker programming. Preventing sudden pauses may be especially important for preventing arrhythmias in the LQTS because such pauses are highly proarrhythmic in this patient population. Unfortunately, properly functioning pacemakers cannot be expected to prevent postextrasystolic pauses. The use of a pause-prevention pacing algorithm-rate smoothing-for preventing pause-dependent torsade de pointes is described in 12 patients with cardiac arrest or syncope due to congenital LQTS who were followed for 21 +/- 11 months.


Asunto(s)
Estimulación Cardíaca Artificial/métodos , Síndrome de QT Prolongado/terapia , Torsades de Pointes/terapia , Algoritmos , Paro Cardíaco/etiología , Frecuencia Cardíaca/fisiología , Humanos , Síndrome de QT Prolongado/complicaciones , Síncope/etiología , Torsades de Pointes/etiología , Torsades de Pointes/fisiopatología
18.
J Card Fail ; 6(3): 276-85, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10997756

RESUMEN

BACKGROUND: Although pharmacological therapy has ameliorated symptoms and improved the survival of patients with chronic heart failure (CHF), this chronic syndrome remains a progressive disease causing incremental morbidity and early mortality. A new therapy for the treatment of CHF should ideally decrease mortality, alleviate symptoms, and improve functional capacity. A growing body of evidence suggests that the use of implantable devices to resynchronize ventricular contraction may be a beneficial adjunct in the treatment of CHF. METHODS: The Comparison of Medical Therapy, Pacing, and Defibrillation in Chronic Heart Failure (COMPANION) trial is a randomized, open-label, 3-arm study of patients in New York Heart Association class III or IV with an ejection fraction of 35% or less and a QRS duration of 120 milliseconds or less. The COMPANION study objectives are to determine whether optimal pharmacological therapy used with (1) ventricular resynchronization therapy alone or (2) ventricular resynchronization therapy combined with cardioverter-defibrillator capability is superior to optimal pharmacological therapy alone in reducing combined all-cause mortality and hospitalizations; reducing cardiac morbidity; improving functional capacity, cardiac performance, and quality of life; and increasing total survival.


Asunto(s)
Fármacos Cardiovasculares/uso terapéutico , Insuficiencia Cardíaca/terapia , Marcapaso Artificial , Ensayos Clínicos Controlados Aleatorios como Asunto , Enfermedad Crónica , Terapia Combinada , Femenino , Insuficiencia Cardíaca/tratamiento farmacológico , Humanos , Masculino , Proyectos de Investigación , Estados Unidos
19.
J Am Coll Cardiol ; 35(5): 1221-7, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10758964

RESUMEN

OBJECTIVE: To measure ventricular contractile synchrony in patients with dilated cardiomyopathy (DCM) and to evaluate the effects of biventricular pacing on contractile synchrony and ejection fraction. BACKGROUND: Dilated cardiomyopathy is characterized by abnormal ventricular activation and contraction. Biventricular pacing may promote a more coordinated ventricular contraction pattern in these patients. We hypothesized that biventricular pacing would improve synchrony of right ventricular and left ventricular (RV/LV) contraction, resulting in improved ventricular ejection fraction. METHODS: Thirteen patients with DCM and intraventricular conduction delay underwent multiple gated equilibrium blood pool scintigraphy. Phase image analysis was applied to the scintigraphic data and mean phase angles computed for the RV and LV. Phase measures of interventricular (RV/LV) synchrony were computed in sinus rhythm and during atrial sensed biventricular pacing (BiV). RESULTS: The degree of interventricular dyssynchrony present in normal sinus rhythm correlated with LV ejection fraction (r = -0.69, p < 0.01). During BiV, interventricular contractile synchrony improved overall from 27.5 +/- 23.1 degrees to 14.1 +/- 13 degrees (p = 0.01). The degree of interventricular dyssynchrony present in sinus rhythm correlated with the magnitude of improvement in synchrony during BiV (r = 0.83, p < 0.001). Left ventricular ejection fraction increased in all thirteen patients during BiV, from 17.2 +/- 7.9% to 22.5 +/- 8.3% (p < 0.0001) and correlated significantly with improvement in RV/LV synchrony during BiV (r = 0.86, p < 0.001). CONCLUSIONS: Dilated cardiomyopathy with intraventricular conduction delay is associated with significant interventricular dyssynchrony. Improvements in interventricular synchrony during biventricular pacing correlate with acute improvements in LV ejection fraction.


Asunto(s)
Estimulación Cardíaca Artificial/métodos , Cardiomiopatía Dilatada/complicaciones , Contracción Miocárdica , Disfunción Ventricular/etiología , Disfunción Ventricular/terapia , Adulto , Anciano , Bloqueo de Rama/complicaciones , Electrocardiografía , Femenino , Imagen de Acumulación Sanguínea de Compuerta , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Volumen Sistólico , Resultado del Tratamiento , Disfunción Ventricular/diagnóstico por imagen , Disfunción Ventricular/fisiopatología
20.
J Am Coll Cardiol ; 35(5): 1276-87, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10758970

RESUMEN

OBJECTIVES: This study was directed at developing spatial 62-lead electrocardiogram (ECG) criteria for classification of counterclockwise (CCW) and clockwise (CW) typical atrial flutter (Fl) in patients with and without structural heart disease. BACKGROUND: Electrocardiographic classification of CCW and CW typical atrial Fl is frequently hampered by inaccurate and inconclusive scalar waveform analysis of the 12-lead ECG. METHODS: Electrocardiogram signals from 62 torso sites and multisite endocardial recordings were obtained during CCW typical atrial Fl (12 patients), CW typical Fl (3 patients), both forms of typical Fl (4 patients) and CCW typical and atypical atrial Fl (1 patient). All the Fl wave episodes were divided into two or three successive time periods showing stable potential distributions from which integral maps were computed. RESULTS: The initial, intermediate and terminal CCW Fl wave map patterns coincided with: 1) caudocranial activation of the right atrial septum and proximal-to-distal coronary sinus activation, 2) craniocaudal activation of the right atrial free wall, and 3) activation of the lateral part of the subeustachian isthmus, respectively. The initial, intermediate and terminal CW Fl wave map patterns corresponded with : 1) craniocaudal right atrial septal activation, 2) activation of the subeustachian isthmus and proximal-to-distal coronary sinus activation, and 3) caudocranial right atrial free wall activation, respectively. A reference set of typical CCW and CW mean integral maps of the three successive Fl wave periods was computed after establishing a high degree of quantitative interpatient integral map pattern correspondence irrespective of the presence or absence of organic heart disease. CONCLUSIONS: The 62-lead ECG of CCW and CW typical atrial Fl in man is characterized by a stereotypical spatial voltage distribution that can be directly related to the underlying activation sequence and is highly specific to the direction of Fl wave rotation. The mean CCW and CW Fl wave integral maps present a unique reference set for improved clinical detection and classification of typical atrial Fl.


Asunto(s)
Aleteo Atrial/clasificación , Aleteo Atrial/diagnóstico , Mapeo del Potencial de Superficie Corporal/métodos , Electrocardiografía/métodos , Endocardio , Sistema de Conducción Cardíaco , Anciano , Algoritmos , Aleteo Atrial/tratamiento farmacológico , Aleteo Atrial/etiología , Aleteo Atrial/fisiopatología , Mapeo del Potencial de Superficie Corporal/instrumentación , Análisis Discriminante , Electrocardiografía/instrumentación , Endocardio/fisiopatología , Femenino , Sistema de Conducción Cardíaco/fisiopatología , Cardiopatías/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Factores de Riesgo , Rotación , Sensibilidad y Especificidad , Factores de Tiempo
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