311 research outputs found
Association of Endogenous Hormones and Bone Mineral Density in Postmenopausal Women
Aim: The aim of this study was to examine the association between endogenous hormones and bone mineral density (BMD) in postmenopausal women. Materials and Methods: This was a cross-sectional study of 798 postmenopausal women aged 47-85 years. Data were collected on age, age at menopause, years since menopause, smoking status, body mass index, adiposity, BMD, physical activity, and Vitamin D supplementation. Measured hormonal parameters were: follicle-stimulating hormone (FSH), estradiol, testosterone, dehydroepiandrosterone sulfate, 4-androstenedione, cortisol, insulin-like growth factor-1, 25-hydroxyvitamin D, and parathormone (PTH) levels. BMD was measured at the lumbar spine, femoral neck, and total hip using dual-energy X-ray absorptiometry. A directed acyclic graph was used to select potential confounding variables. Results: Multivariable analysis showed significant associations between cortisol and femoral neck BMD (β: -0.02, 95% confidence interval [CI]: -0.03 - 0.00), and PTH with femoral neck BMD (β: -0.01, 95% CI: -0.02 - 0.01) and total hip BMD (β: -0.01, 95% CI: -0.01 - 0.00). Hormonal factors more likely associated with a higher risk of low BMD (osteopenia or osteoporosis) were FSH (odds ratio [OR]: 1.02, 95% CI: 1.01-1.03) and PTH (OR: 1.02, 95% CI: 1.01-1.04). Conclusions: Higher cortisol and PTH levels were inversely associated with BMD. Postmenopausal women with higher FSH or PTH levels were likely to have low BMD. © 2023 Journal of Mid-life Health
A new type of doubly silylamido-bridged\ud cyclopentadienyl group 4 metal complexes
Doubly bridged di(silyl-η-amido)cyclopentadienyltitanium and -zirconium complexes and their related cations as the [(PhCH 2)B(C 6F 5) 3] - salts have been isolated (see structure of the Ti derivative). The neutral benzylzirconium complex was a very efficient catalyst in the presence of methylaluminoxane for producing high molecular weight polyethylene and ethylene-1-hexene copolymer
Zirconium and hafnium complexes with (allylsilyl)(η-amidosilyl)-η5-cyclopentadienyl ligands: synthesis, structure and reactivity
The disubstituted cyclopentadiene C5H4(SiMe2Cl)[SiMe2(CH2CH=CH2)] was isolated by reaction of the lithium salt [Li{C5H4SiMe2(CH2CH=CH2)}] with SiMe2Cl2. It was then treated with NH2tBu and LiNH(2,6-Me2C6H3) to give the (aminosilyl)cyclopentadienes C5H4[SiMe2(CH2CH=CH2)][SiMe2(NHR)], which were further deprotonated to their dilithium salts [Li2{1-SiMe2NR-3-SiMe2(CH2CH=CH2)C5H3}] (R = tBu, 2,6-Me2C6H3). Reactions of the metal halides ZrCl4(THF)2 and HfCl4 with these dilithium salts, followed by alkylation of the resulting dichloro complexes, afforded the (η1-amidosilyl)-η5-cyclopentadienyl complexes [M{η5-C5H3(SiMe2-η1-NR)[SiMe2(CH2CH=CH2)]}X2] (R = tBu, 2,6-Me2C6H3; X = Cl, Me, CH2Ph; M = Zr, Hf). Only the bis(iminoacyl) complexes [M{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}{η2-CR=N(2,6-Me2C6H3)}2] (M = Zr, Hf; R = Me, CH2Ph) could be isolated when the dialkylzirconium and -hafnium complexes were treated with CN(2,6-Me2C6H3); these were slowly transformed into the C–C-coupled diazametallacyclopentene compounds [M{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}{η1-N(2,6-Me2C6H3)-CR=CR-η1-N(2,6-Me2C6H3)}] (R = Me, CH2Ph, M = Zr; R = Me, M = Hf) when their toluene solutions were heated to 70 °C–80 °C for long periods (2–4 d). The structural characterisation of all of the new compounds is described and the molecular structure of the dimeric dichlorozirconocene [ZrCl(μ-Cl){η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}]2, was determined by X-ray diffraction methods. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005
Steroid avoidance or withdrawal for kidney transplant recipients
Background: Steroid-sparing strategies have been attempted in recent decades to avoid morbidity from long-term steroid intake among kidney transplant recipients. Previous systematic reviews of steroid withdrawal after kidney transplantation have shown a significant increase in acute rejection. There are various protocols to withdraw steroids after kidney transplantation and their possible benefits or harms are subject to systematic review. This is an update of a review first published in 2009. OBJECTIVES: To evaluate the benefits and harms of steroid withdrawal or avoidance for kidney transplant recipients. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Specialised Register to 15 February 2016 through contact with the Information Specialist using search terms relevant to this review. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials (RCTs) in which steroids were avoided or withdrawn at any time point after kidney transplantation were included. DATA COLLECTION AND ANALYSIS: Assessment of risk of bias and data extraction was performed by two authors independently and disagreement resolved by discussion. Statistical analyses were performed using the random-effects model and dichotomous outcomes were reported as relative risk (RR) and continuous outcomes as mean difference (MD) with 95% confidence intervals. MAIN RESULTS: We included 48 studies (224 reports) that involved 7803 randomised participants. Of these, three studies were conducted in children (346 participants). The 2009 review included 30 studies (94 reports, 5949 participants). Risk of bias was assessed as low for sequence generation in 19 studies and allocation concealment in 14 studies. Incomplete outcome data were adequately addressed in 22 studies and 37 were free of selective reporting.The 48 included studies evaluated three different comparisons: steroid avoidance or withdrawal compared with steroid maintenance, and steroid avoidance compared with steroid withdrawal. For the adult studies there was no significant difference in patient mortality either in studies comparing steroid withdrawal versus steroid maintenance (10 studies, 1913 participants, death at one year post transplantation: RR 0.68, 95% CI 0.36 to 1.30) or in studies comparing steroid avoidance versus steroid maintenance (10 studies, 1462 participants, death at one year after transplantation: RR 0.96, 95% CI 0.52 to 1.80). Similarly no significant difference in graft loss was found comparing steroid withdrawal versus steroid maintenance (8 studies, 1817 participants, graft loss excluding death with functioning graft at one year after transplantation: RR 1.17, 95% CI 0.72 to 1.92) and comparing steroid avoidance versus steroid maintenance (7 studies, 1211 participants, graft loss excluding death with functioning graft at one year after transplantation: RR 1.09, 95% CI 0.64 to 1.86). The risk of acute rejection significantly increased in patients treated with steroids for less than 14 days after transplantation (7 studies, 835 participants: RR 1.58, 95% CI 1.08 to 2.30) and in patients who were withdrawn from steroids at a later time point after transplantation (10 studies, 1913 participants, RR 1.77, 95% CI 1.20 to 2.61). There was no evidence to suggest a difference in harmful events, such as infection and malignancy, in adult kidney transplant recipients. The effect of steroid withdrawal in children is unclear. AUTHORS' CONCLUSIONS: This updated review increases the evidence that steroid avoidance and withdrawal after kidney transplantation significantly increase the risk of acute rejection. There was no evidence to suggest a difference in patient mortality or graft loss up to five year after transplantation, but long-term consequences of steroid avoidance and withdrawal remain unclear until today, because prospective long-term studies have not been conducted
Steroid avoidance or withdrawal for kidney transplant recipients
Background: Steroid-sparing strategies have been attempted in recent decades to avoid morbidity from long-term steroid intake among kidney transplant recipients. Previous systematic reviews of steroid withdrawal after kidney transplantation have shown a significant increase in acute rejection. There are various protocols to withdraw steroids after kidney transplantation and their possible benefits or harms are subject to systematic review. This is an update of a review first published in 2009. OBJECTIVES: To evaluate the benefits and harms of steroid withdrawal or avoidance for kidney transplant recipients. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Specialised Register to 15 February 2016 through contact with the Information Specialist using search terms relevant to this review. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials (RCTs) in which steroids were avoided or withdrawn at any time point after kidney transplantation were included. DATA COLLECTION AND ANALYSIS: Assessment of risk of bias and data extraction was performed by two authors independently and disagreement resolved by discussion. Statistical analyses were performed using the random-effects model and dichotomous outcomes were reported as relative risk (RR) and continuous outcomes as mean difference (MD) with 95% confidence intervals. MAIN RESULTS: We included 48 studies (224 reports) that involved 7803 randomised participants. Of these, three studies were conducted in children (346 participants). The 2009 review included 30 studies (94 reports, 5949 participants). Risk of bias was assessed as low for sequence generation in 19 studies and allocation concealment in 14 studies. Incomplete outcome data were adequately addressed in 22 studies and 37 were free of selective reporting.The 48 included studies evaluated three different comparisons: steroid avoidance or withdrawal compared with steroid maintenance, and steroid avoidance compared with steroid withdrawal. For the adult studies there was no significant difference in patient mortality either in studies comparing steroid withdrawal versus steroid maintenance (10 studies, 1913 participants, death at one year post transplantation: RR 0.68, 95% CI 0.36 to 1.30) or in studies comparing steroid avoidance versus steroid maintenance (10 studies, 1462 participants, death at one year after transplantation: RR 0.96, 95% CI 0.52 to 1.80). Similarly no significant difference in graft loss was found comparing steroid withdrawal versus steroid maintenance (8 studies, 1817 participants, graft loss excluding death with functioning graft at one year after transplantation: RR 1.17, 95% CI 0.72 to 1.92) and comparing steroid avoidance versus steroid maintenance (7 studies, 1211 participants, graft loss excluding death with functioning graft at one year after transplantation: RR 1.09, 95% CI 0.64 to 1.86). The risk of acute rejection significantly increased in patients treated with steroids for less than 14 days after transplantation (7 studies, 835 participants: RR 1.58, 95% CI 1.08 to 2.30) and in patients who were withdrawn from steroids at a later time point after transplantation (10 studies, 1913 participants, RR 1.77, 95% CI 1.20 to 2.61). There was no evidence to suggest a difference in harmful events, such as infection and malignancy, in adult kidney transplant recipients. The effect of steroid withdrawal in children is unclear. AUTHORS' CONCLUSIONS: This updated review increases the evidence that steroid avoidance and withdrawal after kidney transplantation significantly increase the risk of acute rejection. There was no evidence to suggest a difference in patient mortality or graft loss up to five year after transplantation, but long-term consequences of steroid avoidance and withdrawal remain unclear until today, because prospective long-term studies have not been conducted
Steroid avoidance or withdrawal for pancreas and pancreas with kidney transplant recipients
Background Pancreas or kidney‐pancreas transplantation improves survival and quality of life for people with type 1 diabetes mellitus and kidney failure. Immunosuppression after transplantation is associated with complications. Steroids have adverse effects on cardiovascular risk factors such as hypertension, hyperglycaemia or hyperlipidaemia, increase risk of infection, obesity, cataracts, myopathy, bone metabolism alterations, dermatologic problems and cushingoid appearance. Whether avoiding steroids changes outcomes is unclear. Objectives We aimed to assess the safety and efficacy of steroid early withdrawal (treatment for less than 14 days after transplantation), late withdrawal (after 14 days after transplantation) or steroid avoidance in patients receiving a pancreas (including a vascularized organ) alone (PTA), simultaneous with a kidney (SPK) or after kidney transplantation (PAK). Search methods We searched the Cochrane Renal Group's Specialised Register (to 18 June 2014) through contact with the Trials' Search Co‐ordinator. We handsearched: reference lists of nephrology textbooks, relevant studies, recent publications and clinical practice guidelines; abstracts from international transplantation society scientific meetings; and sent emails and letters seeking information about unpublished or incomplete studies to known investigators. Selection criteria We included randomised controlled trials (RCTs) or cohort studies of steroid avoidance (including early withdrawal) versus steroid maintenance or versus late withdrawal in pancreas or pancreas with kidney transplant recipients. We defined steroid avoidance as complete avoidance of steroid immunosuppression, early steroid withdrawal as steroid treatment for less than 14 days after transplantation and late withdrawal as steroid withdrawal after 14 days after transplantation. Data collection and analysis Two authors independently assessed the retrieved titles and abstracts, and where necessary the full text reports to determine which studies satisfied the inclusion criteria. Authors of included studies were contacted to obtain missing information. Statistical analyses were performed using random effects models and results expressed as risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). Cohort studies were not meta‐analysed, but their findings summarised descriptively. Main results Three RCTs enrolling 144 participants met our inclusion criteria. Two compared steroid avoidance versus late steroid withdrawal and one compared late steroid withdrawal versus steroid maintenance. All studies included SPK and only one also included PTA. All studies had an overall moderate risk of bias and presented only short‐term results (six to 12 months). Two studies (89 participants) compared steroid avoidance or early steroid withdrawal versus late steroid withdrawal. There was no clear evidence of an impact on mortality (2 studies, 89 participants: RR 1.64, 95% CI 0.21 to 12.75), risk of kidney loss censored for death (2 studies, 89 participants: RR 0.35, 95% CI 0.04 to 3.09), risk of pancreas loss censored for death (2 studies, 89 participants: RR 1.05, 95% CI 0.36 to 3.04), or acute kidney rejection (1 study, 49 participants: RR 2.08, 95% CI 0.20 to 21.50), however results were uncertain and consistent with no difference or important benefit or harm of steroid avoidance/early steroid withdrawal. The study that compared late steroid withdrawal versus steroid maintenance observed no deaths, no graft loss or acute kidney rejection at six months in either group and reported uncertain effects on acute pancreas rejection (RR 0.88, 95% CI 0.06 to 13.35). Of the possible adverse effects only infection was reported by one study. There were significantly more UTIs reported in the late withdrawal group compared to the steroid avoidance group (1 study, 25 patients: RR 0.41, 95% CI 0.26 to 0.66). We also identified 13 cohort studies and one RCT which randomised tacrolimus versus cyclosporin. These studies in general showed that steroid‐sparing and withdrawal strategies had benefits in lowering HbAc1 and risk of infections (BK virus and CMV disease) and improved blood pressure control without increasing the risk of rejection. However, two studies found an increased incidence of acute pancreas rejection (HR 2.8, 95% CI 0.89 to 8.81, P = 0.066 in one study and 43.3% in the steroid withdrawal group versus 9.3% in the steroid maintenance, P < 0.05 at three years in the other) and one study found an increased incidence of acute kidney rejection (18.7% in the steroid withdrawal group versus 2.8% in the steroid maintenance, P < 0.05) at three years. Authors' conclusions There is currently insufficient evidence for the benefits and harms of steroid withdrawal in pancreas transplantation in the three RCTs (144 patients) identified. The results showed uncertain results for short‐term risk of rejection, mortality, or graft survival in steroid‐sparing strategies in a very small number of patients over a short period of follow‐up. Overall the data was sparse, so no firm conclusions are possible. Moreover, the 13 observational studies findings generally concur with the evidence found in the RCTs
Preparation of imido pentamethylcyclopentadienyl molybdenum(IV) complexes. X-ray molecular structure of cis-[MoCp*CI(η-NtBu)]2·C6H6
The reduction of [MoCp * Cl2(NtBu)] 1 with 1 equiv. of 10% sodium amalgam in the presence of CN(2,6-Me2C6H3) yields the green crystalline compound [MoCp * Cl(NtBuCN(2,6-Me2C6H3)] 2 which can be alkylated by MgClMe to give [MoCp * Me(NtBu)CN(2,6-Me2C6H3)] 3. The same reduction in the absence of ligands leads to an almost equimolar mixture of compounds identified as cis- and trans-[MoCp* (μ-Cl)(NtBu)]24 which are slowly and irreversibly transformed into cis-[MoCp * Cl(μ-NtBu)]25 by heating a toluene solution at 90°C. Compounds (cis + trans)-4 and cis-5 are alkylated by MgClMe leading to the same final methyl derivative [MoCp * Me(μ-NtBu)]26, and react with ethylene to yield the adduct [MoCp * Cl(NtBu)(C2H4)] 7. All new complexes were characterized by their analytical composition, IR and NMR spectroscopy and mass spectrometry, and the structure of the benzene solvate of cis-[MoCp * Cl(μ-NtBu)]25 was determined by X-ray diffraction methods.Italian Consiglio Nazionale delle Ricerch
tert-Butylsilylcyclopentadienyl Group 4 metal complexes
New Group 4 metal t-butyldimethylsilylcyclopentadienyl complexes [MCpCp′Cl2] (Cp=η5-C5H5; Cp′=η5-C5H4SiMe2tBu; M=Ti 4, Zr 5, Hf 6) were prepared by reaction of 1 equiv. of the lithium (2) and thallium (3) salts of t-butyldimethylsilylcyclopentadiene 1 with the monocyclopentadienyl complexes [MCpCl3·DME] (M=Zr, Hf) and [TiCpCl3], respectively. A similar reaction using ZrCl4(THF)2 and HfCl4 with 2 equiv. of the lithium salt 2 gave the symmetric [MCp′2Cl2] ( M=Zr 7, Hf 8) metallocenes. Alkylation of these compounds with 2 equiv. of MgRCl (R=Me, CH2Ph) and Li(CH2CMe2Ph) afforded the dialkyl complexes [MCpCp′R2] (R=Me, M=Zr 9, Hf 10; R=CH2Ph, M=Ti 11, Zr 12, Hf 13), [ZrCp′2(CH2Ph)2] 14 and [ZrCpCp′(CH2CMe2Ph)2] 17. A Similar reaction of 5 with 1 equiv. of Mg(CH2Ph)Cl gave the monobenzyl compound [ZrCpCp′Cl(CH2Ph)] (15). Hydrolysis of 15 with a stoichiometric amount of water afforded the dinuclear μ-oxo compound [(ZrCpCp′Cl)2(μ-O)] (16). All of the new complexes reported were characterized by elemental analysis and 1H and 13C NMR spectroscopy and the molecular structures of 4 and 16 were determined by X-ray diffraction methods. Ethylene polymerization activities were measured for compounds 4–7.Financial support of our work by MCyT (project MAT2001-1309) is gratefully acknowledged. R.W. and C.R. are grateful to DFG, MEC and Repsol S.A. for fellowships
Recurrence Rate and Morbidity after Ultrasound-guided Transvaginal Aspiration of Ultrasound Benign-appearing Adnexal Cystic Masses with and without Sclerotherapy: A Systematic Review and Meta-analysis
To determine the pooled recurrence rate of benign adnexal masses/cysts (namely simple cyst, endometrioma, hydrosalpinx, peritoneal cyst) after transvaginal ultrasound-guided aspiration, with or without sclerotherapy
Aprendizaje colaborativo: interacción oral y percepción del discente. Memoria de la red docente universitaria (2991)
El proyecto de investigación interuniversitario que, desde 2009, está desarrollando una actividad de aprendizaje colaborativo para ejercitar la conversación nativo- no nativo entre discentes italófonos e hispanófonos (Universidad de Alicante, Università Suor Orsola Benincasa de Nápoles y Università degli Studi di Salerno) continúa profundizando en cuestiones que giran en torno a este tema desde ópticas diferentes y confluyentes. La red 2991 de docencia universitaria del ICE de la UA que ha actuado durante el curso 2013-2014, focaliza la atención en un aspecto concreto de la evaluación (ya tratada parcialmente en ediciones anteriores). Se centra en la percepción y la reflexión de los discentes acerca de todo el proceso, desde la organización de la propuesta hasta los elementos lingüísticos y conversacionales que ponen en práctica. Todo ello ha sido planteado basándose en una encuesta que facilitase la comunicación docente/discente y unificara los puntos de interés, en unas ocasiones ofreciendo el uso de respuestas múltiples y en otras dejando abierto el comentario del alumno. La red ha dado origen, además, a dos comunicaciones presentadas en las XII Jornadas de redes de investigación en docencia universitaria celebradas en la UA este 2014, que atendiendo a la lengua de estudio de los discentes, español o italiano, recogen y exponen los resultados generados
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