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OBJECTIVE: To report diaphyseal fractures of the proximal tibia following tibial tuberosity advancement without plate stabilisation for the management of cranial cruciate ligament rupture in dogs. METHODS: Members of the British Veterinary Orthopaedic Association's online discussion forum were invited to submit revision cases of tibial diaphyseal fracture following tibial tuberosity advancement without plate fixation. Data collected included signalment, surgical revision technique, pre- and postoperative revision radiographic findings, complications and veterinary assessment. Owners were invited to complete the Liverpool Osteoarthritis in Dogs questionnaire. RESULTS: A total of 17 dogs were included in the study. Eleven dogs had OrthoFoam-wedge modified Maquet procedures and six had the tibial tuberosity advancement rapid procedure. Tibial tuberosity advancement was maintained in 14/17 cases. Postrevision surgery complications occurred in eight cases: minor complications in 3/17 dogs; major in 5/17 and no catastrophic complications. Surgical site infection was the most common complication (4/8). Final clinical outcome found 8/17 of dogs to have excellent, 8/17 satisfactory and 1/17 poor clinical outcome. The median Liverpool Osteoarthritis in Dogs score was 12/52 (range 2 to 28). Final outcome was 6/13 owners that were very satisfied, 2/13 owners indifferent and 5/13 owners very disappointed. CLINICAL SIGNIFICANCE: This is the first case series reporting tibial diaphyseal fractures following tibial tuberosity advancement without plate stabilisation. The authors report here a wide spectrum of potential fixation strategies should one of these fractures occur.
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Lesiones del Ligamento Cruzado Anterior/veterinaria , Ligamento Cruzado Anterior/cirugía , Perros , Fracturas de la Tibia/veterinaria , Animales , Lesiones del Ligamento Cruzado Anterior/cirugía , Diáfisis , Perros/lesiones , Perros/cirugía , Femenino , Masculino , Complicaciones Posoperatorias/veterinaria , Estudios Retrospectivos , Rodilla de Cuadrúpedos/cirugía , Tibia , Fracturas de la Tibia/cirugíaRESUMEN
OBJECTIVES: To evaluate complications, short- and medium-term outcomes following treatment of lameness associated with cranial cruciate ligament insufficiency in dogs using the "TTA-Rapid" technique. METHODS: Patient records from two veterinary clinics were retrospectively examined to collect data from cases treated over a period of 21 months. An owner postal questionnaire using a clinical metrology instrument (Liverpool Osteoarthritis in Dogs) evaluated medium-term outcome of at least six months. RESULTS: In total 152 procedures were carried out in 141 dogs by two surgeons. Major complications, requiring further intervention, were identified in 11 (7%). Nine of these involved "late" meniscal injuries and two sustained tibial fractures postoperatively, one requiring internal fixation and the other external coaptation. The 3-month outcome was considered satisfactory in 99% of 135 procedures whilst the medium-term outcome (mean 16 months) was considered satisfactory in 86% of 108 dogs. CLINICAL SIGNIFICANCE: "TTA-Rapid" offers a treatment option for cranial cruciate-deficient stifles with good short- and medium-term outcomes. The complication rate was low in our hands.
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Ligamento Cruzado Anterior/cirugía , Enfermedades de los Perros/cirugía , Cojera Animal/cirugía , Osteotomía/veterinaria , Rodilla de Cuadrúpedos/cirugía , Animales , Ligamento Cruzado Anterior/diagnóstico por imagen , Perros , Femenino , Masculino , Osteotomía/métodos , Evaluación de Resultado en la Atención de Salud , Complicaciones Posoperatorias/veterinaria , Radiografía/veterinaria , Estudios Retrospectivos , Rodilla de Cuadrúpedos/diagnóstico por imagen , Rodilla de Cuadrúpedos/lesionesRESUMEN
Anaphylaxis is a severe, life-threatening, generalised hypersensitivity reaction. It affects 1 in 1,333 (~0.08%) of the English population during their lives, with 1% of cases being fatal. Management, underpinned by guidance from the Resuscitation Council (UK), focuses on a thorough clinical assessment and prompt administration of intramuscular adrenaline. Symptoms may recur, so patients must be observed for a period of no less than six hours. In a deployed environment evacuation must be swift and into a safe environment capable of providing critical care support. There are clear occupational implications following a case of anaphylaxis, and a confirmed case may affect service personnel's fitness to deploy. This article will summarise the management of anaphylaxis in Royal Naval personnel.
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Anafilaxia/tratamiento farmacológico , Epinefrina/uso terapéutico , Medicina Naval/métodos , Simpatomiméticos/uso terapéutico , Albuterol/uso terapéutico , Broncodilatadores/uso terapéutico , Manejo de la Enfermedad , Glucocorticoides/uso terapéutico , Antagonistas de los Receptores Histamínicos/uso terapéutico , Humanos , Inyecciones Intramusculares , Planificación de Atención al Paciente , Guías de Práctica Clínica como Asunto , Derivación y Consulta , Autocuidado , Automanejo , Triptasas/sangreRESUMEN
Super-Typhoon Haiyan struck the Philippines on 7 November 2013. The initial reports estimated 10 000 fatalities and four million displaced persons. As the United Kingdom's initial response to this disaster, HMS DARING was diverted from her deployment to take part in humanitarian aid, named Operation PATWIN. This article will outline the medical aspects of the relief effort undertaken and aim to identify any lessons that may inform future operations.
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Tormentas Ciclónicas , Planificación en Desastres , Medicina Militar , Personal Militar , Altruismo , Tormentas Ciclónicas/estadística & datos numéricos , Planificación en Desastres/organización & administración , Trastornos de Estrés por Calor/epidemiología , Humanos , Medicina Militar/organización & administración , Evaluación de Necesidades , Filipinas , Reino Unido , Heridas y Lesiones/epidemiologíaRESUMEN
OBJECTIVE: To report the signalment and clinical features of dogs with non-traumatic lateral patellar luxation and to report the complications and outcomes following surgery. METHODS: A multicentre retrospective study was performed. Medical records were reviewed and the signalment, clinical features, and treatment of dogs presenting with lateral patellar luxation were recorded. In dogs treated surgically, the outcome and complications were investigated. RESULTS: Sixty-five dogs (95 stifles) were included; 39 were male and median age at presentation was 10 months. Breeds were classified as small (n = 6), medium (n = 23), large (n = 27), and giant (n = 9). Lateral patellar luxation was classified as grade I (n = 14), II (n = 41), III (n = 29), and IV (n = 11). Conformational abnormalities were noted in 34 stifles; genu valgum was the most common (n = 28). Higher-grade luxation was associated with a younger age at presentation (p = 0.032) and genu valgum (p = 0.01). Surgery was performed on 58 stifles, 22 of which sustained one or more complications; 16 complications were managed conservatively, four with implant removal and six with revision surgery. Surgeon-assessed outcome was good or excellent in 47 of the 51 dogs available for review. CONCLUSIONS: Non-traumatic lateral patellar luxation is a disease of predominantly medium and large breed dogs. It has several similar clinical features and can be surgically treated in a similar manner to medial patellar luxation with similar types of complications and outcomes expected.
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Perros/lesiones , Luxaciones Articulares/veterinaria , Rótula/lesiones , Animales , Perros/cirugía , Femenino , Luxaciones Articulares/cirugía , Masculino , Rótula/cirugía , Estudios Retrospectivos , Rodilla de Cuadrúpedos/lesiones , Rodilla de Cuadrúpedos/cirugía , Resultado del TratamientoRESUMEN
The Intermediate Command and Staff Course (Maritime) is an eight-week residential course held at the Joint Services Command and Staff College, Shrivenham. It is designed to prepare mid-late-seniority Lieutenants and newly-promoted Lieutenant Commanders of the Royal Navy for command, charge and staff appointments, and also to assess their suitability for further staff training. This paper aims to assist officers in the Royal Navy Medical Services in their preparation for attending this course, and also to familiarise them with aspects of the course.
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Educación Profesional/organización & administración , Personal Militar/educación , Comunicación , Humanos , Liderazgo , Reino UnidoAsunto(s)
Artrodesis/veterinaria , Huesos del Carpo/lesiones , Carpo Animal/lesiones , Gatos/cirugía , Perros/cirugía , Fracturas Óseas/veterinaria , Luxaciones Articulares/veterinaria , Animales , Huesos del Carpo/cirugía , Carpo Animal/cirugía , Femenino , Fracturas Óseas/cirugía , Luxaciones Articulares/cirugía , Cojera Animal/etiología , Cojera Animal/cirugía , Masculino , Resultado del TratamientoRESUMEN
Islet transplantation is a promising treatment for diabetes but long-term success is limited by progressive graft loss. Aggregates of the beta cell peptide islet amyloid polypeptide (IAPP) promote beta cell apoptosis and rapid amyloid formation occurs in transplanted islets. Porcine islets are an attractive alternative islet source as they demonstrate long-term graft survival. We compared the capacity of transplanted human and porcine islets to form amyloid as an explanation for differences in graft survival. Human islets were transplanted into streptozotocin-diabetic immune-deficient mice. Amyloid deposition was detectable at 4 weeks posttransplantation and was associated with islet graft failure. More extensive amyloid deposition was observed after 8 weeks. By contrast, no amyloid was detected in transplanted neonatal or adult porcine islets that had maintained normoglycemia for up to 195 days. To determine whether differences in IAPP sequence between humans and pigs could explain differences in amyloid formation and transplant viability, we sequenced porcine IAPP. Porcine IAPP differs from the human sequence at 10 positions and includes substitutions predicted to reduce its amyloidogenicity. Synthetic porcine IAPP was considerably less amyloidogenic than human IAPP as determined by transmission electron microscopy, circular dichroism, and thioflavin T binding. Viability assays indicated that porcine IAPP is significantly less toxic to INS-1 beta cells than human IAPP. Our findings demonstrate that species differences in IAPP sequence can explain the lack of amyloid formation and improved survival of transplanted porcine islets. These data highlight the potential of porcine islet transplantation as a therapeutic approach for human diabetes.
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Amiloide/metabolismo , Trasplante de Islotes Pancreáticos , Islotes Pancreáticos/metabolismo , Secuencia de Aminoácidos , Amiloide/química , Amiloide/fisiología , Animales , Dicroismo Circular , Rechazo de Injerto , Humanos , Polipéptido Amiloide de los Islotes Pancreáticos , Ratones , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Especificidad de la Especie , PorcinosRESUMEN
OBJECTIVES: The aim of this study was to determine if internal fixation of the anconeus combined with a proximal ulnar osteotomy was more likely to result in fusion of the anconeus to the ulna compared with a proximal ulnar osteotomy alone. METHODS: A total of 12 orthopaedic referral clinics reviewed their clinical databases for cases of ununited anconeal process. Demographic and clinical parameters were collected along with radiographic follow-up at a minimum of four weeks. Cases treated with proximal ulnar osteotomy alone were compared with those treated with proximal ulnar osteotomy + internal fixation. Both groups were compared for background and disease variables. We tested for an association between treatment method and whether radiographic anconeal union had occurred. RESULTS: A total of 47 elbows (44 dogs) were identified. Of these, 28 cases (average age 7.6 months) were treated with proximal ulnar osteotomy (of which eight were stabilised with an intramedullary pin) alone. Nineteen cases (average age 7.1 months) were treated with proximal ulnar osteotomy + internal fixation. The two groups were not significantly different in age (P=0.638, Mann-Whitney U test). Fourteen of 28 cases with proximal ulnar osteotomy alone displayed anconeal union at follow-up compared with 16 of 19 cases of proximal ulnar osteotomy + internal fixation, and this difference was statistically significant (P=0.029, Fisher's exact test). CLINICAL SIGNIFICANCE: These data suggest that use of a lag screw to stabilise and compress the ununited anconeal process in addition to proximal ulnar osteotomy produces a better radiographic outcome. It is argued that radiographic union of the anconeus is likely to be associated with better long-term clinical outcome but further studies are required to confirm this.
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Tornillos Óseos/veterinaria , Perros/lesiones , Fijación Interna de Fracturas/veterinaria , Osteotomía/veterinaria , Fracturas del Cúbito/veterinaria , Animales , Perros/cirugía , Femenino , Fijación Interna de Fracturas/instrumentación , Fijación Interna de Fracturas/métodos , Curación de Fractura/fisiología , Cojera Animal/diagnóstico por imagen , Cojera Animal/cirugía , Masculino , Radiografía , Fracturas del Cúbito/diagnóstico por imagen , Fracturas del Cúbito/cirugíaRESUMEN
The medical records of 155 dogs with patellar luxation (PL) from three different centres were analysed. Each case was classified according to the nature of its luxation and any concurrent orthopaedic conditions plus the age at diagnosis were also noted. Measurements relating to angle of inclination (AOI) of the femoral neck and medio-lateral bowing of the femur and tibia at the stifle were also recorded. The femoral and tibial data were compared to dogs with another orthopaedic condition in a case-control assessment. Labradors were most commonly affected (21%). Most luxations were medial (92%) and 54% of affected dogs were female. The mean AOI of the hip was 148.95 degrees . There was a statistically significant difference between the stifles of dogs with PL compared to a control population. This study concluded that PL in large breeds is increasing. Lateral luxation was uncommon and was not associated exclusively with large breeds. Females were more likely to have PL than males and being female was a risk factor associated with coxa valga. There are significant differences in medio-lateral stifle conformation between dogs with PL and control dogs.
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Peso Corporal/fisiología , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/patología , Rótula/patología , Luxación de la Rótula/veterinaria , Animales , Cruzamiento , Enfermedades de los Perros/diagnóstico por imagen , Perros , Femenino , Masculino , Rótula/anatomía & histología , Rótula/diagnóstico por imagen , Luxación de la Rótula/diagnóstico por imagen , Luxación de la Rótula/epidemiología , Luxación de la Rótula/patología , Prevalencia , Radiografía , Factores de Riesgo , Factores Sexuales , Rodilla de Cuadrúpedos/anatomía & histología , Rodilla de Cuadrúpedos/diagnóstico por imagen , Rodilla de Cuadrúpedos/patologíaRESUMEN
ABSTRACT Two fungi were isolated from grapevines in Michigan vineyards with Eutypa dieback symptoms: Eutypa lata and Eutypella vitis. These fungi are difficult to distinguish morphologically but are genetically distinct as determined by sequencing of the internal transcribed spacer (ITS) regions. The ITS regions of 25 Eutypa lata and 15 Eutypella vitis isolates were sequenced. Eutypa lata sequences were more variable than those of Eutypella vitis. Polymerase chain reaction (PCR) primers were designed for each species and evaluated against isolates of both fungi as well as 11 closely related Diatrypaceous fungi and 23 isolates of other fungi representing various pathogenic, saprophytic, and endophytic genera on grape and other small fruit crops. The primers were specific for their intended species. A nested multiplex PCR protocol was developed and used to successfully detect these fungi in wood samples from cankers with and without stromata from naturally infected vines as well as in artificially inoculated, potted canes. The primers developed in this study will assist in our abilities to diagnose and study the roles of Eutypa lata and Eutypella vitis in Eutypa dieback development.
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The mucin MUC7 is a glycoprotein that plays a role in bacterial clearance and has candidacidal activity. There are two common allelic forms with 5 or 6 tandem repeats (TR) of a 23 amino acid motif within the highly glycosylated (mucin) domain. The MUC7*5 allele has previously been shown to be less prevalent in patients with asthma, suggesting a protective role in respiratory function. Here we report the characterisation of other frequent genetic variation within and in the vicinity of the gene MUC7. A total of 26 polymorphisms were identified of which 5 are located in transcribed regions. A subset of 8 polymorphisms was selected to represent the major haplotypes, and allelic association was studied in individuals of Northern European ancestry, including known asthmatics. There was low haplotype diversity and strong association between each of the loci, and the MUC7*5 allele-carrying haplotype remained the one most strongly associated with asthma. Five of these polymorphisms have also been tested in the 1946 longitudinal birth cohort, for whom developmental, environmental and respiratory health data are available. We show that the haplotype carrying MUC7*5 is associated with higher FEV1 at 53 years, reduced age-related decline of FEV1, and also reduced incidence of wheeze.
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Asma/genética , Mucinas/genética , Polimorfismo de Nucleótido Simple , Trastornos Respiratorios/genética , Adolescente , Adulto , Niño , Preescolar , Estudios de Cohortes , Europa (Continente)/epidemiología , Femenino , Volumen Espiratorio Forzado/genética , Frecuencia de los Genes , Haplotipos , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Proteínas y Péptidos SalivalesRESUMEN
BACKGROUND: Jacobs and Bovasso reported (Psychological Medicine 2000, 30, 669-678) that maternal death in childhood and chronic severe depression in adulthood were associated with subsequent breast cancer. We have examined the effects of parental loss in childhood and psychiatric disorder in adult life on breast cancer risk using a national birth cohort study. METHOD: Eighty-three cases of breast cancer were diagnosed in a study of 2253 women followed from birth to age 59 years. Cox proportional hazards models were used to test whether breast cancer rates were higher in women who experienced parental death and divorce before age 16, psychiatric disorders between 15 and 32 years, symptoms of anxiety and depression at 36 years, or use of antidepressant medication at 31 or 36 years than in women who did not have these experiences. RESULTS: There was no overall association between parental death, parental divorce or psychiatric disorder and the incidence of breast cancer. There was some evidence that women with more severe psychiatric disorders between the ages of 15 and 32 years were more likely to develop breast cancer early. The interaction between parental divorce and severe psychiatric disorder was non-significant (p=0.1); however, the group who experienced both these events had an increased breast cancer risk compared with those who experienced neither [hazard ratio (HR) 2.64, 95% confidence interval (CI) 1.13-6.19]. CONCLUSIONS: Our study does not provide strong support for the hypothesis that early loss or adult psychiatric disorders are associated with breast cancer. A meta-analysis is needed that uses data from all available cohort studies and investigates possible interactive effects on breast cancer risk.
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Neoplasias de la Mama/epidemiología , Divorcio/estadística & datos numéricos , Acontecimientos que Cambian la Vida , Trastornos Mentales/epidemiología , Padres , Adolescente , Adulto , Factores de Edad , Niño , Preescolar , Estudios de Cohortes , Femenino , Humanos , Incidencia , Lactante , Recién Nacido , Persona de Mediana Edad , Prevalencia , Reino Unido/epidemiologíaRESUMEN
AIMS/HYPOTHESIS: We assessed whether low birthweight or early adiposity rebound was more strongly associated with type 2 diabetes, and whether any effect of low birthweight or early adiposity rebound was explained by adult BMI, adult height, social class of subject or of his/her father, or maternal or paternal diabetes. METHODS: Cox's proportional hazard models were used on data from the National Birth Cohort Study (the MRC National Survey of Health and Development), which was begun in 1946 and had self-reported physician-diagnosed diabetes with age at onset ranging from 31 to 53 years (n=78 cases, and n=47 cases in the multivariate analysis) as the outcome. RESULTS: A U-shaped association between birthweight and type 2 diabetes rates was close to statistical significance (quadratic term p value=0.08). Younger age at adiposity rebound was associated with increased rates of type 2 diabetes (test for trend p=0.002), the association being robust to adjustment for each of sex, birthweight, weight at 2 years, father's social class, parental diabetes, and own social class. The effect of early adiposity rebound was very slightly reduced by adjustment for sex and adult height (p=0.003), but considerably reduced after adjustment for sex and adult BMI (test for trend p=0.1), and further reduced (p=0.4) after additional adjustment for birthweight, weight at 2 years, adult height, social class of subject and of his/her father, and parental diabetes. CONCLUSIONS/INTERPRETATION: Early adiposity rebound was associated with an increased rate of type 2 diabetes independently of birthweight, but its effect was mostly through high adult BMI. Parental diabetes and possibly low weight at 2 years were also risks.
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Adiposidad , Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/fisiopatología , Crecimiento/fisiología , Recién Nacido de Bajo Peso , Adolescente , Adulto , Peso al Nacer/fisiología , Estatura , Índice de Masa Corporal , Niño , Preescolar , Estudios de Cohortes , Diabetes Mellitus Tipo 2/etiología , Femenino , Predisposición Genética a la Enfermedad , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Masculino , Síndrome Metabólico/complicaciones , Síndrome Metabólico/epidemiología , Persona de Mediana Edad , Análisis Multivariante , Obesidad/complicaciones , Obesidad/epidemiología , Prevalencia , Modelos de Riesgos Proporcionales , Factores de Riesgo , Caracteres Sexuales , Clase Social , Reino Unido/epidemiologíaRESUMEN
OBJECTIVES: To investigate cardiovascular risk factors and changes in risk factor levels in relation to menopausal stage, hysterectomy status and hormone replacement therapy use in a cohort of women aged 53 years with prospective data on smoking, lifetime socio-economic circumstances, and blood pressure and obesity at age 43 years. DESIGN: A prospective study. SETTING: England, Scotland and Wales. POPULATION: A cohort of women from the Medical Research Council Survey of Health and Development. METHODS: A total of 1303 women, aged 53 years, from a UK birth cohort study with measures of cardiovascular risk factors were classified by five menopausal status groups (premenopause, perimenopause, postmenopause, hysterectomy and hormone replacement therapy user). Body mass index, glycosolated haemoglobin, blood pressure, high density lipoprotein, low density lipoprotein and total cholesterol measurements were taken, and analysed within the groups taking confounding variables into account. Changes in body mass index and blood pressure measurement in the same women obtained when 43 years of age were also compared. MAIN OUTCOME MEASURES: Body mass index, glycosolated haemoglobin, blood pressure, high density lipoprotein, low density lipoprotein and total cholesterol. RESULTS: At 53 years, body mass index, waist circumference, total and low density lipoprotein cholesterol, and glycosolated haemoglobin (HbA1c) varied by menopausal status group, but blood pressure did not. Levels of total cholesterol and HbA1c increased across the natural menopause transition, before and after adjustment for body mass index, smoking and lifetime socio-economic circumstances. After adjustment for confounders, levels of risk factors for hysterectomised women were similar to those of naturally postmenopausal women. Women on hormone replacement therapy had lower levels of total and low density lipoprotein cholesterol, HbA1c, and were less obese than postmenopausal women. The lower obesity levels were partly due to these women already being less obese at age 43 years. CONCLUSIONS: This study showed that naturally postmenopausal or hysterectomised women had higher levels of metabolic risk factors compared with premenopausal or perimenopausal women of the same age. The long term stability of these differences and their translation into variations in incidence of cardiovascular disease remain to be seen. The lower levels of metabolic risk factors for women on hormone replacement therapy may protect against future cardiovascular disease or may be overwhelmed by other adverse, and as yet unknown, effects of hormone replacement therapy.
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Enfermedades Cardiovasculares/inducido químicamente , Terapia de Reemplazo de Hormonas/efectos adversos , Menopausia/fisiología , Presión Sanguínea/fisiología , Índice de Masa Corporal , Enfermedades Cardiovasculares/epidemiología , Estudios de Cohortes , Femenino , Hemoglobina Glucada/análisis , Humanos , Histerectomía/estadística & datos numéricos , Lípidos/sangre , Persona de Mediana Edad , Estudios Prospectivos , Análisis de Regresión , Factores de Riesgo , Reino Unido/epidemiologíaRESUMEN
In a retrospective review of 43 femoral fractures, three dogs had separation of the femoral capital epiphysis from the metaphysis in the absence of trauma. Two of these dogs also had evidence of pathology in the contralateral femoral neck including, in one dog, displacement of the capital epiphysis in relation to the metaphysis without actual separation. The case histories, radiographic features and histopathological findings of these cases were reviewed and compared with previous cases of slipped capital femoral epiphysis (SCFE) reported in dogs and also with SCFE in children. Pre-slip, acute, chronic and acute-on-chronic slips were Identified. Based on the cases reviewed, the authors advise internal fixation of stable slipped epiphyses in dogs. This may also be appropriate for unstable separations, although resorption of the femoral neck may preclude stable fixation and necessitate femoral head and neck excision.
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Epífisis Desprendida/veterinaria , Fracturas del Fémur/veterinaria , Animales , Niño , Perros , Epífisis Desprendida/diagnóstico por imagen , Epífisis Desprendida/patología , Epífisis Desprendida/cirugía , Femenino , Fracturas del Fémur/diagnóstico por imagen , Fracturas del Fémur/patología , Fracturas del Fémur/cirugía , Cabeza Femoral/diagnóstico por imagen , Cabeza Femoral/patología , Cabeza Femoral/cirugía , Cuello Femoral/diagnóstico por imagen , Cuello Femoral/patología , Cuello Femoral/cirugía , Humanos , Fijadores Internos/veterinaria , Masculino , Radiografía , Estudios Retrospectivos , Heridas y Lesiones/veterinariaRESUMEN
Although the life course prospective study design has many benefits, and information from such studies is in increasing demand for scientific and policy purposes, it has potential inherent design problems associated with its longevity. These are in particular the fixed sample structure and the data collected in early life, which are each determined by the scientific principles of another time and the risk over time of increased sample loss and distortion through loss. The example of a national birth cohort in Britain, studied from birth so far to age 53 years is used to address these questions. Although the response rate is high, avoidable loss, which was low in childhood, increased in adulthood, and was highest in those in adverse socio-economic circumstances and those with low scores on childhood cognitive measures. Recent permanent refusal rate rises may be the result of better tracing and/or a response to increased requests for biological measurement. Nevertheless, the responding sample continues in most respects to be representative of the national population of a similar age. Consistency of response over the study's 20 data collections has been high. The size of the sample responding in adulthood is adequate for the study of the major costly diseases, and for the study of functional ageing and its precursors. This study's continuation has depended not only on scientific value but also policy relevance. Although the problems inherent in the prospective design are unavoidable they are not, in the study described, a barrier to scientific and policy value. That seems also likely in Britain's two later born national birth cohort studies that have continued into adulthood.
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Demografía , Estudios Longitudinales , Vigilancia de la Población/métodos , Adolescente , Adulto , Niño , Preescolar , Emigración e Inmigración/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mortalidad , Pacientes Desistentes del Tratamiento , Factores Socioeconómicos , Factores de Tiempo , Reino Unido/epidemiologíaRESUMEN
A method of simultaneously measuring the changes in cerebral blood volume (CBV) and T(*) (2) that occur on brain activation with high temporal resolution was developed. The method involves measuring the change in the longitudinal relaxation time (T(1)) that occurs following a bolus injection of Gd-DTPA and converting this measurement to a change in blood volume assuming fast exchange. The sequence was optimized for the measurement of changes in CBV with high temporal resolution. A change in CBV of 27 +/- 4% on activation of the primary visual cortex (V1) was measured across four subjects. The time course of changes in T(*) (2) showed a poststimulus undershoot (P = 0.008) corresponding approximately to a period over which CBV was still elevated above baseline, but falling (P = 0.01). The effects of perfusion, nonfulfillment of the assumption of fast exchange and of intrinsic T(1) changes on activation on the model used to calculate the change in CBV are discussed.
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Circulación Cerebrovascular , Medios de Contraste/administración & dosificación , Imagen Eco-Planar/métodos , Gadolinio DTPA/administración & dosificación , Corteza Visual/irrigación sanguínea , Adulto , Volumen Sanguíneo , Humanos , Procesamiento de Imagen Asistido por Computador , MasculinoRESUMEN
This work aimed to investigate the effects of administering Gd-DTPA on the BOLD effect, and to determine the feasibility of using this approach to measure fractional changes in blood volume and blood oxygenation on neuronal activation during a visual paradigm. A linear relationship between cortical R(2)(*) and the intravascular concentration of Gd-DTPA was demonstrated. The change in R(2)(*) in the visual cortex on activation at 3 T (in the absence of Gd-DTPA) was found to be 1.38 +/- 0.31 s(-1) (N = 4). The fractional change in total blood volume during visual activation was calculated to be 28% +/- 7% (N = 4). The absolute increase in venous blood oxygenation on activation (DeltaY) was estimated to be 21% +/- 4% (N = 4) (assuming HCT = 0.4, resting blood oxygenation = 60%, fraction of volume change that was venous = 36%, and the resting venous fraction of the blood volume = 70%). Simulations showed that the estimated change in venous blood oxygenation was sensitive to the assumed venous blood fraction, and that the estimated fractional change in blood oxygenation was insensitive to whether the change in blood volume occurred in the arterial or venous network.