Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Public Health ; 235: 15-25, 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39033718

RESUMEN

OBJECTIVES: The COVID-19 pandemic and associated lockdowns disrupted health care worldwide. High-income countries observed a decrease in preterm births during lockdowns, but maternal pregnancy-related outcomes were also likely affected. This study investigates the effect of the first COVID-19 lockdown (March-June 2020) on provision of maternity care and maternal pregnancy-related outcomes in the Netherlands. STUDY DESIGN: National quasi-experimental study. METHODS: Multiple linked national registries were used, and all births from a gestational age of 24+0 weeks in 2010-2020 were included. In births starting in midwife-led primary care, we assessed the effect of lockdown on provision of care. In the general pregnant population, the impact on characteristics of labour and maternal morbidity was assessed. A difference-in-regression-discontinuity design was used to derive causal estimates for the year 2020. RESULTS: A total of 1,039,728 births were included. During the lockdown, births to women who started labour in midwife-led primary care (49%) more often ended at home (27% pre-lockdown, +10% [95% confidence interval: +7%, +13%]). A small decrease was seen in referrals towards obstetrician-led care during labour (46%, -3% [-5%,-0%]). In the overall group, no significant change was seen in induction of labour (27%, +1% [-1%, +3%]). We found no significant changes in the incidence of emergency caesarean section (9%, -1% [-2%, +0%]), obstetric anal sphincter injury (2%, +0% [-0%, +1%]), episiotomy (21%, -0% [-2%, +1%]), or post-partum haemorrhage: >1000 ml (6%, -0% [-1%, +1%]). CONCLUSIONS: During the first COVID-19 lockdown in the Netherlands, a substantial increase in homebirths was seen. There was no evidence for changed available maternal outcomes, suggesting that a maternity care system with a strong midwife-led primary care system may flexibly and safely adapt to external disruptions.

2.
J Perinatol ; 44(2): 217-223, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37853089

RESUMEN

OBJECTIVE: To investigate trends in low Apgar scores in (near) term singletons using the Dutch Perinatal Registry. METHODS: In a cohort of 1,583,188 singletons liveborn ≥35 weeks of gestation in the period 2010-2019, we studied trends in low 5-min Apgar scores (<7 and <4) using Cochrane Armitage trend tests. RESULTS: The proportion of infants with low Apgar scores <7 and <4 increased significantly between 2010-2019 (1.04-1.42% (p < 0.001), 0.17-0.19% (p = 0.009), respectively). Neonatal mortality remained unchanged. Induction of labour, epidural analgesia and planned caesarean section showed an increasing trend. Instrumental vaginal delivery and emergency caesarean section were performed less frequently over time, but these intervention subgroups showed the highest relative increase in infants with low Apgar scores. CONCLUSIONS: In the Netherlands, the risk of a low 5-min Apgar score increased over the last decade. The highest relative increase was observed in subgroups of instrumental vaginal delivery and emergency caesarean section.


Asunto(s)
Enfermedades del Recién Nacido , Trabajo de Parto , Lactante , Recién Nacido , Embarazo , Humanos , Femenino , Cesárea , Estudios de Cohortes , Puntaje de Apgar , Parto Obstétrico
3.
BMC Pregnancy Childbirth ; 21(1): 767, 2021 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-34772364

RESUMEN

BACKGROUND: The COVID-19 pandemic led to regional or nationwide lockdowns as part of risk mitigation measurements in many countries worldwide. Recent studies suggest an unexpected and unprecedented decrease in preterm births during the initial COVID-19 lockdowns in the first half of 2020. The objective of the current study was to assess the effects of the two months of the initial national COVID-19 lockdown period on the incidence of very and extremely preterm birth in the Netherlands, stratified by either spontaneous or iatrogenic onset of delivery, in both singleton and multiple pregnancies. METHODS: Retrospective cohort study using data from all 10 perinatal centers in the Netherlands on very and extremely preterm births during the initial COVID-19 lockdown from March 15 to May 15, 2020. Incidences of very and extremely preterm birth were calculated using an estimate of the total number of births in the Netherlands in this period. As reference, we used data from the corresponding calendar period in 2015-2018 from the national perinatal registry (Perined). We differentiated between spontaneous versus iatrogenic onset of delivery and between singleton versus multiple pregnancies. RESULTS: The incidence of total preterm birth < 32 weeks in singleton pregnancies was 6.1‰ in the study period in 2020 versus 6.5‰ in the corresponding period in 2015-2018. The decrease in preterm births in singletons was solely due to a significant decrease in iatrogenic preterm births, both < 32 weeks (OR 0.71; 95%CI 0.53 to 0.95) and < 28 weeks (OR 0.53; 95%CI 0.29 to 0.97). For multiple pregnancies, an increase in preterm births < 28 weeks was observed (OR 2.43; 95%CI 1.35 to 4.39). CONCLUSION: This study shows a decrease in iatrogenic preterm births during the initial COVID-19-related lockdown in the Netherlands in singletons. Future studies should focus on the mechanism of action of lockdown measures and reduction of preterm birth and the effects of perinatal outcome.


Asunto(s)
COVID-19/prevención & control , Trabajo de Parto Inducido/tendencias , Nacimiento Prematuro/epidemiología , Nacimiento Prematuro/etiología , Femenino , Política de Salud , Humanos , Enfermedad Iatrogénica/epidemiología , Incidencia , Recien Nacido Extremadamente Prematuro , Recién Nacido , Modelos Logísticos , Países Bajos/epidemiología , Embarazo , Atención Prenatal/métodos , Atención Prenatal/tendencias , Factores Protectores , Estudios Retrospectivos , Factores de Riesgo
4.
BMC Pregnancy Childbirth ; 19(1): 4, 2019 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-30606140

RESUMEN

BACKGROUND: The postpartum period is an important period for preventive strategies as common maternal and child health risks may become manifest. Women with a lower socioeconomic status tend to have lower maternal empowerment. Increasing their risks of adverse maternal and child health outcomes. This study aims to assess the effectiveness of a primary care level intervention. Delivered to maternity care assistants, aiming to increase maternal empowerment postpartum. METHODS: This study is part of the Dutch nationwide "Healthy Pregnancy 4 All-2" (HP4All-2) program, which aims to identify vulnerable mothers and young children at risk of adverse health outcomes, and subsequently improve their care. This program targets women from deprived neighborhoods. A pragmatic cluster randomized controlled trial will be undertaken in 12 maternity care organizations. Maternity care organizations in urban municipalities (i.e. the clusters) will be randomized to either a systematic risk assessment during pregnancy with emphasis on identification of non-medical risk factors for adverse maternal and neonatal health outcomes, and subsequent adaptation of care towards a client-tailored approach during pregnancy and the postpartum period, or solely the systematic risk assessment. The primary outcome is the prevalence of a low maternal empowerment score postpartum. Secondary maternal outcomes cover health-related quality of life, postnatal depression, smoking, alcohol consumption, illicit drug use. Finally, maternal and neonatal health care utilization postpartum are recorded. All outcomes will be analyzed according to the intention-to-treat principle, using multi-level mixed effects models. DISCUSSION: The study will contribute to evidence regarding the effectiveness of client-tailored, risk-based maternity care to increase maternal empowerment postpartum. TRIAL REGISTRATION: Netherlands Trial Registry (NTR) 6311 , registered 03-27-2017.


Asunto(s)
Participación del Paciente/métodos , Atención Dirigida al Paciente/métodos , Atención Posnatal/métodos , Atención Prenatal/métodos , Atención Primaria de Salud/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto , Ciudades , Análisis por Conglomerados , Depresión Posparto/epidemiología , Depresión Posparto/etiología , Femenino , Humanos , Países Bajos , Ensayos Clínicos Pragmáticos como Asunto , Embarazo , Complicaciones del Embarazo/epidemiología , Complicaciones del Embarazo/etiología , Resultado del Embarazo , Evaluación de Programas y Proyectos de Salud , Calidad de Vida , Medición de Riesgo , Factores de Riesgo , Población Urbana
5.
JDR Clin Trans Res ; 3(1): 10-27, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30370334

RESUMEN

Periodontal disease is very common during pregnancy. Although it has been linked to adverse pregnancy outcomes, systematic reviews have reached discrepant conclusions on these links. Therefore, we conducted a systematic overview of systematic reviews studying the association between periodontal disease and adverse pregnancy outcomes. We searched 6 online databases up to November 2016 and hand-searched references and citations of eligible papers. Systematic reviews of studies comparing pregnancy outcomes among women with and without periodontal disease were eligible for inclusion. Primary outcomes were maternal mortality, preterm birth, and perinatal mortality. Two reviewers extracted data and assessed risk of bias of individual systematic reviews. Findings are described in tabular and narrative form. Twenty-three systematic reviews (including between 3 and 45 studies) were included. None reported the association between periodontal disease and maternal or perinatal mortality. Systematic reviews with the lowest risk of bias consistently demonstrated positive associations between periodontal disease and preterm birth (relative risk, 1.6; 95% confidence interval, 1.3 to 2.0; 17 studies, 6,741 participants), low birth weight (LBW; relative risk, 1.7; 95% CI, 1.3 to 2.1; 10 studies, 5,693 participants), preeclampsia (odds ratio, 2.2; 95% CI, 1.4 to 3.4; 15 studies, 5,111 participants), and preterm LBW (relative risk 3.4; 95% CI, 1.3 to 8.8; 4 studies, 2,263 participants). Based on these figures, estimated population-attributable fractions for periodontal disease were 5% to 38% for preterm birth, 6% to 41% for LBW, and 10% to 55% for preeclampsia. In terms of limitations, as several primary studies did not adjust for confounding, meta-analyses may have overestimated the strength of the associations under study. Due to substantial overlap in included primary studies, we could not aggregate results across reviews. Consistent evidence from systematic reviews with low risk of bias indicates that pregnant women with periodontal disease are at increased risk of developing preeclampsia and delivering a preterm and/or LBW baby (PROSPERO: CRD42015030132). Knowledge Transfer Statement: This study highlights that periodontal disease is an important risk factor for several common adverse pregnancy outcomes. Clinicians should be aware of this link to guide risk selection. Research is needed to develop novel preventive and treatment strategies.

6.
Ned Tijdschr Geneeskd ; 160: D869, 2017.
Artículo en Holandés | MEDLINE | ID: mdl-28098043

RESUMEN

- In this article we give a short overview of new insights into the effects of smoking on health, both on smokers themselves and on those who are exposed to other people's tobacco smoke.- The number of diseases and conditions that are known to be caused by active smoking has now risen to over thirty.- The risk of premature death is not, as previously thought, twice as high in smokers as in non-smokers, but actually three times as high.- Passive smoking too has been shown to have a whole range of negative effects on health.- Further, the causal mechanisms of, amongst other things, the development of cancer, ischaemic heart disease and nicotine dependence under the influence of smoking have been largely unravelled.- Various issues require further investigation; these include the effect of smoking on psychological health and the effects of 'third-hand' smoke. In the meantime, a concerted campaign against this consumer product with its deleterious effects of the health of the population is overdue.


Asunto(s)
Estado de Salud , Fumar/efectos adversos , Humanos , Cese del Hábito de Fumar , Contaminación por Humo de Tabaco , Fumar Tabaco , Tabaquismo
7.
Ned Tijdschr Geneeskd ; 161: D563, 2017.
Artículo en Holandés | MEDLINE | ID: mdl-28120730

RESUMEN

OBJECTIVE: Study the association between the introduction of tobacco control policies in the Netherlands and changes in perinatal outcomes. DESIGN: National quasi-experimental study. METHOD: We used Netherlands Perinatal Registry data (now called Perined) for the period 2000-2011. We studied whether the introduction of smoke-free legislation in workplaces plus a tobacco tax increase and mass media campaign in January 2004, and extension of the smoke-free law to the hospitality industry accompanied by another tax increase and media campaign in July 2008, was associated with changes in perinatal outcomes. We studied all singleton births (gestational age: 24+0 to 42+6 weeks). Our primary outcome measures were: perinatal mortality, preterm birth and being small-for-gestational-age (SGA). Interrupted time series logistic regression analyses were performed to investigate changes in these outcomes occurred after the introduction of the aforementioned tobacco control policies (ClinicalTrials.gov: NCT02189265). RESULTS: Among 2,069,695 singleton births, 13,027 (0.6%) perinatal deaths, 116,043 (5.6%) preterm live-births and 187,966 (9.1%) SGA live-births were observed. The policies introduced in January 2004 were not associated with significant changes in any of the primary outcome measures. A -4.4% (95% CI: -6.4 to -2.4; p < 0.001) decrease in odds of a SGA birth was observed after the policy extension in July 2008 to include a smoke-free hospitality industry, a further tax increase and another media campaign. This translates to an estimated over 500 cases of SGA being averted per year. CONCLUSION: A reduction in SGA births, but not preterm birth or perinatal mortality, was observed in the Netherlands after extension of the smoke-free workplace law to include bars and restaurants, in conjunction with a tax increase and media campaign in 2008.

8.
BJOG ; 118(2): 113-22, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21054759

RESUMEN

BACKGROUND: There is debate concerning the safety and efficacy of antenatal steroids in preterm labour with suspected intrauterine infection (chorioamnionitis). OBJECTIVES: We performed a systematic literature review and meta-analysis aimed at evaluating the efficacy and safety of antenatal steroids in clinical and histological chorioamnionitis. SEARCH STRATEGY: MEDLINE, EMBASE, BioMed Central and the Cochrane databases were searched using the terms 'chorioamnionitis OR intrauterine infection' and '*steroids OR *corticoids'. SELECTION CRITERIA: Studies that reported selected neonatal outcome measures in preterm infants with clinical or histological chorio-amnionitis, according to antenatal steroid exposure, were eligible. DATA COLLECTION AND ANALYSIS: Study selection, data extraction and data analysis were performed by two independent investigators. The meta-analysis techniques used included: Mantel-Haenszel analysis; an assessment of study heterogeneity using the Q statistic; and Egger's regression test and funnel plots, to assess publication bias. MAIN RESULTS: Seven observational studies were included. In histological chorioamnionitis (five studies), antenatal steroids were associated with reduced mortality (OR = 0.45; 95% CI = 0.30-0.68; P = 0.0001), respiratory distress syndrome (OR = 0.53; 95% CI = 0.40-0.71; P < 0.0001), patent ductus arteriosus (OR = 0.56; 95% CI = 0.37-0.85; P = 0.007), intraventricular haemorrhage (IVH; OR = 0.35; 95% CI = 0.18-0.66; P = 0.001) and severe IVH (OR = 0.39; 95% CI = 0.19-0.82; P = 0.01). In clinical chorioamnionitis (four studies), antenatal steroids were associated with reduced severe IVH (OR = 0.29; 95% CI = 0.10-0.89; P = 0.03) and periventricular leucomalacia (OR = 0.35; 95% CI = 0.14-0.85; P = 0.02). CONCLUSIONS: Antenatal steroids may be safe and reduce adverse neonatal outcome after preterm birth associated with chorioamnionitis. There is a need for randomised clinical trials to address this issue.


Asunto(s)
Corticoesteroides/efectos adversos , Corioamnionitis/tratamiento farmacológico , Enfermedades del Prematuro/inducido químicamente , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Atención Prenatal/métodos , Esteroides/efectos adversos , Femenino , Humanos , Recién Nacido , Recien Nacido Prematuro , Embarazo , Resultado del Embarazo
9.
J Perinatol ; 30 Suppl: S21-30, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20877404

RESUMEN

The bacterial infection of chorion and amnion is a common finding in premature delivery and is referred to as chorioamnionitis. As the mother rarely shows symptoms of a systemic inflammation, the course of chorioamnionitis is frequently asymptomatic and chronic. In contrast, the fetal inflammatory response syndrome represents a separate phenomenon, including umbilical inflammation and increased serum levels of proinflammatory cytokines in the fetus. Ascending maternal infections frequently lead to systemic fetal inflammatory reaction. Clinical studies have shown that antenatal exposure to inflammation puts the extremely immature neonates at a high risk for worsening pulmonary, neurological and other organ development. Interestingly, the presence of chorioamnionitis is associated with a lower rate of neonatal mortality in extremely immature newborns. In the following review, the pathogeneses of inflammation-associated perinatal morbidity are outlined. The concept of fetal multiorganic disease during intrauterine infection is introduced and discussed.


Asunto(s)
Corioamnionitis/microbiología , Animales , Infecciones Bacterianas/fisiopatología , Infecciones Bacterianas/transmisión , Corioamnionitis/metabolismo , Corioamnionitis/patología , Corioamnionitis/fisiopatología , Modelos Animales de Enfermedad , Femenino , Feto/anomalías , Feto/fisiopatología , Humanos , Recién Nacido , Recien Nacido Prematuro , Transmisión Vertical de Enfermedad Infecciosa , Interleucina-6/sangre , Malformaciones del Sistema Nervioso/etiología , Malformaciones del Sistema Nervioso/fisiopatología , Embarazo , Complicaciones Infecciosas del Embarazo/fisiopatología , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología , Síndrome de Dificultad Respiratoria del Recién Nacido/fisiopatología
12.
Arch Dis Child Fetal Neonatal Ed ; 94(3): F218-25, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19131431

RESUMEN

A considerable body of human and animal experimental evidence links antenatal inflammation to both accelerated maturation and adverse development of the lung. Initial reports suggest that in preterm infants histological chorioamnionitis is associated with a decreased incidence of respiratory distress syndrome (RDS), while the incidence of bronchopulmonary dysplasia (BPD) is increased. Considerable variation exists in the findings of subsequent human studies, largely dependent on differences in inclusion and exclusion criteria. Taking these differences into account, recent studies generally seem to confirm the effect of chorioamnionitis on RDS incidence, while no effect on BPD is seen. The increased use of antenatal steroids and the diminished effects of secondary pro-inflammatory hits seem to explain part of this change. Additional research is needed to explore these complex interactions and their underlying mechanisms, and evaluate the long term pulmonary effects of antenatal inflammation.


Asunto(s)
Displasia Broncopulmonar/etiología , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología , Antiinflamatorios/administración & dosificación , Displasia Broncopulmonar/epidemiología , Corioamnionitis/epidemiología , Corioamnionitis/patología , Femenino , Madurez de los Órganos Fetales , Humanos , Hidrocortisona/administración & dosificación , Recién Nacido , Recien Nacido Prematuro , Pulmón/fisiopatología , Embarazo , Atención Prenatal , Síndrome de Dificultad Respiratoria del Recién Nacido/epidemiología
13.
Ned Tijdschr Geneeskd ; 152(43): 2341-5, 2008 Oct 25.
Artículo en Holandés | MEDLINE | ID: mdl-19024066

RESUMEN

OBJECTIVE: To evaluate the different methods of detection of breast cancer in women who at time of diagnosis underwent screening mammographies as participants in the Dutch National Breast Cancer Screening Programme (BOB group), and in women who participated in an intensive screening programme for a familial or genetic predisposition to breast cancer (FAM group). DESIGN: Partly retrospective, partly prospective, descriptive. METHOD: All patients who had surgery for invasive breast cancer at the VU University Medical Center, Amsterdam, the Netherlands, from 1 January 1995 to 30 June 2006 and who were participating in one of the abovementioned screening programmes at the time of diagnosis, were included. Data concerning the palpability of the tumour at time of diagnosis and the diagnostic method that first led to breast cancer being diagnosed, were collected. RESULTS: The BOB group consisted of 397 women with invasive carcinoma of which 57% (227/397) tumours were palpable at the time of diagnosis. The majority (64%; 146/227) of the palpable tumours were discovered by breast self-examination as an interval carcinoma. 31% (71/227) were detected by screening mammography and were also palpable. During the same period, 490 women participated in the high risk screening programme; in this FAM group, 23 invasive tumours were detected. A total of 61% (14/23) of these lesions were found during breast self-examination; 7 lesions (30%) were found by imaging. CONCLUSION: In women who participated in one of the 2 screening programmes, the majority of invasive breast cancers were palpable and more than half were detected by breast self-examination. Performing breast self-examination on a regular basis may contribute to early detection of breast cancer. Therefore, the teaching of breast self-examination to women should be encouraged, even if they are participating in a breast cancer screening programme.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/genética , Autoexamen de Mamas/métodos , Mamografía/métodos , Anciano , Femenino , Predisposición Genética a la Enfermedad , Pruebas Genéticas , Humanos , Tamizaje Masivo , Persona de Mediana Edad , Vigilancia de la Población , Sensibilidad y Especificidad , Factores de Tiempo
14.
Arch Dis Child ; 90(12): 1293-6, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16159904

RESUMEN

BACKGROUND: Pyridoxine dependent epilepsy is a rare cause of seizures in childhood. The diagnosis is made on clinical criteria, that in many cases are never met. Therefore, epidemiological data on pyridoxine dependency are scarce. AIMS: To study the epidemiology of pyridoxine dependent epilepsy in the Netherlands, and to determine whether the diagnosis is based on the appropriate criteria. METHODS: Nationwide all departments of paediatrics (n = 113) and of paediatric or neonatal neurology (n = 17) were asked to report cases of pyridoxine dependent seizures. Birth incidences were calculated using national data on live births from 1991 to 2003. RESULTS: Response was received from 67% of paediatric departments, including all university hospitals and 94% of child neurology departments. Thirteen patients were reported. Four definite (31%), three probable (23%), and four possible cases (31%) were identified. Two cases (15%) did not meet criteria for either of these groups. The birth incidence was 1:396,000 for definite and probable cases and 1:252,000 when possible cases are included. CONCLUSIONS: Thus far, epidemiological data on pyridoxine dependent seizures were only available from the UK and Ireland. A higher incidence was found in the Netherlands, in accordance with earlier suggestions of a regional difference. The study shows that the diagnosis is often made without performance of a formal trial of withdrawal. The importance of confirming the diagnosis, concerning the consequences as for individual prognosis, the potential side effects of prolonged pyridoxine substitution, and the possibility of treating the mother in case of future pregnancies are emphasised.


Asunto(s)
Epilepsia/epidemiología , Piridoxina/uso terapéutico , Complejo Vitamínico B/uso terapéutico , Epilepsia/diagnóstico , Epilepsia/tratamiento farmacológico , Femenino , Humanos , Incidencia , Recién Nacido , Masculino , Países Bajos/epidemiología
15.
Acta Orthop Belg ; 67(1): 24-31, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11284268

RESUMEN

The objective of this study was to define the role, indications and outcome of plating in femur shaft fractures. All femoral shaft fractures admitted and treated by the authors during a 2-year period were analysed. The authors personally treated a total of 135 femur fractures. Of these 135 fractures, 15 (11%) were treated with primary plating. The femoral fractures were classified as grade I (n = 4), grade III (n = 3), grade IV (n = 4), grade V (n = 3), and grade VII (n = 1) (OTA classification). Three patients sustained open fractures (one grade I and two grade II, Gustilo and Anderson classification). Pelvic (6) or ipsilateral lower extremity injuries (4) occurred in 10 of the 15 patients. A total of 23 body areas were injured, most commonly the chest (n = 10), abdomen (n = 5), head (n = 6) and blood vessels (n = 3). There were no infections reported. Two implant failures were noted. Femur plating is a useful technique in polytrauma patients for specific indications where intramedullary nailing (IMN) may be contra-indicated or technically not feasible. Although the postoperative morbidity (ARDS, death) in our study seems to be lower after plating than after intramedullary nailing, the rate of complications of fracture healing (30%) is significantly greater with femur plating than with intramedullary nailing (12%).


Asunto(s)
Placas Óseas/efectos adversos , Placas Óseas/normas , Fracturas del Fémur/cirugía , Fijación Interna de Fracturas/efectos adversos , Fijación Interna de Fracturas/instrumentación , Adolescente , Adulto , Anciano , Femenino , Fracturas del Fémur/clasificación , Fracturas del Fémur/diagnóstico por imagen , Fijación Interna de Fracturas/métodos , Curación de Fractura , Humanos , Masculino , Persona de Mediana Edad , Morbilidad , Radiografía , Estudios Retrospectivos , Resultado del Tratamiento
16.
Clin Orthop Relat Res ; (343): 213-23, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9345227

RESUMEN

A sheep study was performed to compare the in vivo performance of bone plates of 316L stainless steel and a new titanium alloy, titanium + 13% niobium + 13% zirconium (Ti-13Nb-13Zr), which had been subjected to a diffusion hardening treatment to produce a blue, wear resistant surface. Bone plates and screws of stainless steel and diffusion hardened Ti-13Nb-13Zr were implanted in adult sheep, in one group (with unosteotomized femurs) for 16 weeks, and in the other (with osteotomized femurs) for 8 weeks. At harvest, the diffusion hardened Ti-13Nb-13Zr devices had superior fixation strength, with greater screw torque out strength and fewer loose screws. In the osteotomized animals, the femurs with diffusion hardened Ti-13Nb-13Zr plates had higher torsional strength after removal of the implants; however, the difference was not statistically significant. In the unosteotomized animals, the torsional strength of the femurs was identical for both materials. There was a slightly reduced incidence of infection (bacterial adhesion) for the sheep with diffusion hardened Ti-13Nb-13Zr implants. In a parallel in vitro study, the magnetic resonance imaging compatibility of Ti-13Nb-13Zr was significantly superior to that of stainless steel. This indicates that diffusion hardened Ti-13Nb-13Zr may be an attractive alternative material for osteosynthesis.


Asunto(s)
Aleaciones , Placas Óseas , Acero Inoxidable , Titanio , Aleaciones/química , Animales , Adhesión Bacteriana , Tornillos Óseos , Fenómenos Químicos , Química Física , Color , Difusión , Modelos Animales de Enfermedad , Contaminación de Equipos , Fémur/fisiopatología , Fémur/cirugía , Fijación Interna de Fracturas/instrumentación , Granuloma de Cuerpo Extraño/etiología , Incidencia , Imagen por Resonancia Magnética , Magnetismo , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Osteotomía/instrumentación , Osteotomía/métodos , Ovinos , Acero Inoxidable/química , Estrés Mecánico , Propiedades de Superficie , Infección de la Herida Quirúrgica/etiología , Titanio/química , Torque
17.
Gastroenterology ; 76(3): 548-55, 1979 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-428709

RESUMEN

Electron microprobe analysis, x-ray diffraction, and infrared spectroscopy have been used to investigate the nature and arrangement of materials present in gallstones. Calcium phosphate and carbonate deposits present centrally in many stones were mixed with a pigmented phase containing copper and protein. In several stones, the central calcium deposits were surrounded by discrete adjacent layers of calcium bilirubinate and cholesterol. The calcium bilirubinate layer was distinguished from other pigmented layers by its higher protein content and increased iron/copper ratio. This sequence of calcium salt and cholesterol deposition occurred in the outer layers of some stones. The phase relationships shown by the present study are consistent with a biphasic mechanism of stone growth in which calcium salts and lipid were alternately deposited. Calcium salt precipitation has been inferred to initiate the sequence as calcium salts were found at the stone centers. The layer sequence has been discussed in terms of some possible effects of damage to the gallbladder wall caused by the calcium salt deposits.


Asunto(s)
Colelitiasis , Adulto , Anciano , Apatitas/análisis , Bilirrubina/análisis , Carbonato de Calcio/análisis , Fosfatos de Calcio/análisis , Colesterol/análisis , Cobre/análisis , Cristalografía , Femenino , Humanos , Hierro/análisis , Magnesio/análisis , Masculino , Persona de Mediana Edad , Fósforo/análisis , Proteínas/análisis , Azufre/análisis
18.
Gut ; 18(10): 836-42, 1977 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-590843

RESUMEN

Detailed information on the structure and composition of gallstones was obtained using an electron probe microanalyser in conjunction with the other methods. Gallstones were studied layer by layer without greatly disturbing the arrangement of the materials present. Elements, including trace elements such as copper, iron, and manganese, were identified and their distributions mapped. The range of the method was extended to determine the character and distribution of certain chemical groups present by treating sections of gallstone with reagents which contained easily detected elements. The nature of the bonding of the sulphur in the stones was studied by examining the sulphur-X-ray spectrum. Pigmented sulphur-containing deposits were found to contain sulphur in a low valence state but taurine conjugates and the sulphate groups of mucosubstances were not detected. Microcrystalline apatite present in the stones contained some manganese and seemed to be implicated in the absorption of the low valence sulphur compound and in the nucleation of some stones.


Asunto(s)
Colelitiasis/metabolismo , Microanálisis por Sonda Electrónica , Calcio/análisis , Humanos , Microscopía Electrónica de Rastreo , Fósforo/análisis , Azufre/análisis , Difracción de Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...