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1.
J Microsc ; 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38415368

RESUMO

Long-term placement of facial implants requires avoiding the formation of fibrous tissue capsules around the artificial material by creating osteoconductive properties of the surface. Most promising approach is the deposition coatings made of materials very similar to bone mineral components, that is, calcium phosphates such as hydroxyapatite (HAp). As part of the research work, an innovative, cost-effective atmospheric pressure plasma deposition (APPD) system was used as a low-temperature coating technology for generating the HAp coatings deposition. Full microstructural characterisation of the coatings using SEM and TEM techniques was carried out in the work. It has been shown that the fully crystalline HAp powder undergoes a transformation during the coatings deposition and the material had a quasi-sintered structure after deposition. The crystalline phase content increased at the coating/substrate interface, while the surface of the HAp was amorphous. This is a very beneficial phenomenon due to the process of bioresorption. The amorphous phase undergoes much faster biodegradation than the crystalline one. In order to increase the bioactivity of the HAp, Zn particles were introduced on the surface of the coating. The TEM microstructural analysis in conjunction with the qualitative analysis of the EDS chemical composition showed that the binding of the Zn particles within the HAp matrix had diffusive character, which is very favourable from the point of view of the quality of the adhesion and the bioactivity of the coating. In the case of such a complex structure and due to its very porous nature, micromechanical analysis was carried out in situ in SEM, that is, by microhardness measurements of both the HAp matrix and the Zn particle. It was shown that the average value of HAp microhardness was 4.395 GPa ± 0.08, while the average value of Zn microhardness was 1.142 GPa ± 0.02.

2.
World J Urol ; 38(12): 3085-3090, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32103332

RESUMO

INTRODUCTION: Prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET/CT) represents the upcoming standard for the staging of prostate cancer (PCa). However, there is still an unmet need for the validation of PSMA PET/CT at primary staging and consecutive histological correlation. Consequently, we decided to analyze the prediction parameter of PSMA PET/CT at primary staging. METHODS: We relied on 90 ≥ intermediate-risk PCa patients treated with radical prostatectomy (RP) and extended pelvic lymph node dissection. All patients were administered to 68Ga-PSMA PET/CT prior to surgery. 68Ga-PSMA PET/CT data were retrospectively reevaluated by a single radiologist and consequently compared to histological results from RP. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the detection of lymph node metastases were analyzed per-patient (n = 90), per-pelvic side (n = 180), and per-anatomic-region (external iliac artery and vein left/right vs. obturator fossa left/right vs. internal iliac artery left/right) (n = 458), respectively. RESULTS: Sensitivity, specificity, PPV, and NPV per-patient were: 43.8, 96.0, 70.0, and 88.8%, respectively. Sensitivity, specificity, PPV, and NPV per-pelvic-side were: 42.9, 95.6, 56.3, and 92.7%, respectively. Sensitivity, specificity, PPV, and NPV per-anatomic-region were: 47.6, 98.9, 66.7, and 97.5%, respectively. CONCLUSIONS: Negative 68Ga-PSMA PET/CT results were highly reliable in our study. Positive 68Ga-PSMA PET/CT results, however, revealed less reliable results. Larger and ideally prospective trials are justified to clarify the potential role of PSMA PET/CT based primary staging.


Assuntos
Ácido Edético/análogos & derivados , Oligopeptídeos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Prostatectomia/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Compostos Radiofarmacêuticos , Idoso , Correlação de Dados , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Excisão de Linfonodo , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Neoplasias da Próstata/cirurgia , Estudos Retrospectivos
3.
BJOG ; 126(7): 926-934, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30461170

RESUMO

OBJECTIVE: We evaluated residual incontinence, depression, and quality of life among Malawian women who had undergone vesicovaginal fistula (VVF) repair 12 or more months previously. DESIGN: Prospective cohort study. SETTING: Fistula Care Centre in Lilongwe, Malawi. POPULATION: Women who had undergone VVF repair in Lilongwe, Malawi at least 12 months prior to enrolment. METHODS: Self-report of urinary leakage was used to evaluate for residual urinary incontinence; depression was evaluated with the Patient Health Questionnaire-9; quality of life was evaluated with the King's Health Questionnaire. MAIN OUTCOME MEASURES: Prevalence and predictors of residual incontinence, quality of life scores, and prevalence of depression and suicidal ideation. RESULTS: Fifty-six women (19.3%) reported residual urinary incontinence. In multivariable analyses, predictors of residual urinary incontinence included: pre-operative Goh type 3 [adjusted risk ratio (aRR) 2.82; 95% confidence interval (CI) 1.61-5.27) or Goh type 4 1.08-2.78), positive postoperative cough stress test (aRR = 2.42; 95% CI 1.24-4.71) and the positive 1-hour postoperative pad test (aRR = 2.20; 95% CI 1.08-4.48). Women with Goh types 3 and 4 VVF reported lower quality of life scores. Depressive symptoms were reported in 3.5% of women; all reported residual urinary incontinence. CONCLUSIONS: While the majority of women reported improved outcomes in the years following surgical VVF repair, those with residual urinary incontinence had a poorer quality of life. Services are needed to identify and treat this at-risk group. TWEETABLE ABSTRACT: Nearly one in five women reported residual urinary incontinence at follow up, 12 or months after vesicovaginal fistula repair.


Assuntos
Transtorno Depressivo/etiologia , Complicações na Gravidez/psicologia , Qualidade de Vida , Incontinência Urinária/psicologia , Fístula Vesicovaginal/cirurgia , Adolescente , Adulto , Transtorno Depressivo/epidemiologia , Feminino , Humanos , Malaui/epidemiologia , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Gravidez , Complicações na Gravidez/epidemiologia , Prevalência , Estudos Prospectivos , Incontinência Urinária/epidemiologia , Fístula Vesicovaginal/epidemiologia , Fístula Vesicovaginal/psicologia , Adulto Jovem
4.
J Fish Biol ; 91(5): 1449-1474, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29110303

RESUMO

The characterization and quantification of diets of nine commercially important Celtic Sea fish species (black-bellied angler Lophius budegassa, blue whiting Micromesistius poutassou, Atlantic cod Gadus morhua, haddock Melanogrammus aeglefinus, European hake Merluccius merluccius, megrim Lepidorhombus whiffiagonis, European plaice Pleuronectes platessa, common sole Solea solea and whiting Merlangius merlangus) was undertaken November 2014 and November 2015 to gain a better understanding of fish feeding strategies, prey preferences, competition for resources and, more generally, increases knowledge of marine ecosystem functioning. Prey were classified into 39 taxonomic groups. A feeding overlap index and multivariate analyses were used to classify the fishes into four main trophic groups where interspecific competition for resources may be important: piscivorous species, omnivorous species, planktivorous species and invertebrate benthic feeders. Ontogenetic changes in diet were also considered for L. budegassa, G. morhua, M. aeglefinus, M. merluccius and M. merlangus through partitioning into size classes. This revealed an important shift in the diet of M. merluccius from omnivory to piscivory, whereas M. aeglefinus exhibited no significant ontogenetic change in diet, remaining an invertebrate benthic feeder. Feeding strategies of these species were also investigated using the Shannon niche-breadth index and other descriptors, such as the total number of taxonomic groups of prey and the mean number of prey in gut contents.


Assuntos
Dieta , Ecossistema , Peixes/fisiologia , Animais , Comportamento Alimentar , Peixes/crescimento & desenvolvimento , França , Irlanda , Estado Nutricional , Oceanos e Mares , Reino Unido
5.
BJOG ; 124(6): 966-972, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28128507

RESUMO

OBJECTIVE: Determine whether a 1-hour pad test at discharge can identify continence status within 120 days of obstetric vesicovaginal fistula (VVF) repair. DESIGN: Prospective cohort study. SETTING: Fistula Care Centre in Lilongwe, Malawi. POPULATION: Women with VVF who underwent repair between January 2012 and December 2014. METHODS: Data on demographics, obstetric history, physical exam findings, operative management, postoperative findings, and follow up evaluations were collected on women with VVF repair. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values (PPV and NPV), and a receiver operating curve (ROC) were calculated to assess the utility of using a discharge pad test at three thresholds to identify women likely to be continent at follow up. RESULTS: After VVF repair, 346 women had a 1-hour pad test performed at the time of hospital discharge and completed follow up within 120 days of repair. Of these, 79.8% (n = 276) were completely continent, whereas 20.2% (n = 70) had some degree of incontinence. The sensitivity and specificity of a negative 1-hour pad test at predicting continence is 68.1% and 82.9%, respectively. With this prevalence, a negative pad test at a 1.5-g threshold demonstrates a high predictive value (PPV = 94.0%, 95% CI 90.0-96.9) in detecting women with continence after repair. CONCLUSIONS: At the 1.5-g threshold, a negative pad test at discharge identifies 94% of women who will remain continent after VVF repair. Adding the pad test to fistula care can identify women who are likely to remain continent and may not need further therapies in settings where resources are limited and follow up after repair is difficult. TWEETABLE ABSTRACT: A negative pad test after repair is associated with continued continence at follow up.


Assuntos
Absorventes Higiênicos , Complicações Pós-Operatórias/diagnóstico , Complicações na Gravidez/cirurgia , Incontinência Urinária/diagnóstico , Fístula Vesicovaginal/cirurgia , Adulto , Feminino , Humanos , Malaui/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Período Pós-Operatório , Valor Preditivo dos Testes , Gravidez , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade , Resultado do Tratamento , Incontinência Urinária/epidemiologia , Incontinência Urinária/etiologia
6.
BJOG ; 123(5): 831-6, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26853525

RESUMO

OBJECTIVE: To compare primiparous and multiparous women who develop obstetric fistula (OF) and to assess predictors of fistula location. DESIGN: Cross-sectional study. SETTING: Fistula Care Centre at Bwaila Hospital, Lilongwe, Malawi. POPULATION: Women with OF who presented between September 2011 and July 2014 with a complete obstetric history were eligible for the study. METHODS: Women with OF were surveyed for their obstetric history. Women were classified as multiparous if prior vaginal or caesarean delivery was reported. The location of the fistula was determined at operation: OF involving the urethra, bladder neck, and midvagina were classified as low; OF involving the vaginal apex, cervix, uterus, and ureters were classified as high. MAIN OUTCOME MEASURES: Demographic information was compared between primiparous and multiparous women using chi-squared and Mann-Whitney U-tests. Multivariate logistic regression models were implemented to assess the relationship between variables of interest and fistula location. RESULTS: During the study period, 533 women presented for repair, of which 452 (84.8%) were included in the analysis. The majority (56.6%) were multiparous when the fistula formed. Multiparous women were more likely to have laboured <1 day (62.4 versus 44.5%, P < 0.001), delivered a live-born infant (26.8 versus 17.9%, P = 0.026), and have a high fistula location (37.5 versus 11.2%, P < 0.001). Multiparity [adjusted odds ratio (aOR) = 4.55, 95% confidence interval (CI) 2.27-9.12)] and history of caesarean delivery (aOR = 4.11, 95% CI 2.45-6.89) were associated with development of a high fistula. CONCLUSIONS: Multiparity was common in our cohort, and these women were more likely to have a high fistula. Additional research is needed to understand the aetiology of high fistula including potential iatrogenic causes. TWEETABLE ABSTRACT: Multiparity and caesarean delivery were associated with a high tract fistula in our Malawian cohort.


Assuntos
Paridade , Fístula Urinária/etiologia , Doenças Uterinas/etiologia , Fístula Vaginal/etiologia , Adulto , Cesárea/efeitos adversos , Estudos Transversais , Feminino , Humanos , Modelos Logísticos , Malaui , Análise Multivariada , Razão de Chances , Gravidez , Fatores de Risco , Fístula Urinária/diagnóstico , Doenças Uterinas/diagnóstico , Fístula Vaginal/diagnóstico
7.
J Fish Biol ; 82(5): 1720-7, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23639166

RESUMO

The effects of nuptial colour, parasites and body size on reproductive success were examined in a natural population of three-spined stickleback Gasterosteus aculeatus. Reproductive males were collected, with the contents of their nests, during the embryo-guarding stage from Lynne Lake (Cook Inlet, Alaska, U.S.A.), and nuptial colour, infection status and body size were recorded. Regression analysis revealed that male body size was the only predictor, of those measured, of reproductive success in nature.


Assuntos
Tamanho Corporal , Doenças dos Peixes/parasitologia , Doenças Parasitárias em Animais/patologia , Pigmentos Biológicos/fisiologia , Smegmamorpha/fisiologia , Animais , Masculino , Análise de Regressão , Reprodução
8.
Nervenarzt ; 82(7): 880-5, 2011 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-20953756

RESUMO

Previous studies have indicated high prevalence rates of mental disorders among prisoners. Based on a sample of 98 male German long-term prisoners and 94 male German short-term prisoners, psychiatric symptoms were comparatively assessed by means of the brief symptom inventory (BSI). The study showed a considerable increased in psychological stress, especially with regard to long-term prisoners. In this context a significant difference (p<0.01) was found between short-term and long-term prisoners where 65% of long-term prisoners and 40% of short-term prisoners showed a noticeable increase in the amount of psychological stress. Furthermore, high prevalence rates of a history of attempted suicide (29.7%) and self-injurious behavior (43.2%) were found. The following clinical implications are deduced from this study: there is a general need for treatment during imprisonment, especially with respect to long-term prisoners. In addition, the high rates of attempted suicide and self-injurious behavior require a focus on a more elaborated crisis management as well as psychotherapeutic treatment for this population.


Assuntos
Prisioneiros/psicologia , Prisioneiros/estatística & dados numéricos , Comportamento Autodestrutivo/epidemiologia , Comportamento Autodestrutivo/psicologia , Estresse Psicológico/epidemiologia , Estresse Psicológico/psicologia , Adolescente , Adulto , Idoso , Comorbidade , Alemanha/epidemiologia , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prevalência , Medição de Risco , Fatores de Tempo , Adulto Jovem
9.
Fortschr Neurol Psychiatr ; 77(3): 152-9, 2009 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-19283650

RESUMO

Previous studies indicate high prevalence rates of mental disorders and trauma among prisoners. Based on a sample of 102 male German prisoners, the comorbidity and childhood trauma experiences in 72 criminals with antisocial personality disorder were investigated. Furthermore, associations of antisocial personality disorder and early traumatic experiences with the age at first conviction and the lifetime months of imprisonment were examined. Subjects had high rates of comorbid lifetime and current disorders as well as childhood trauma experiences. Physical abuse in childhood and adolescence was identified as a predictor for lifetime months of imprisonment, antisocial personality disorder was found to be a predictor for the age at first conviction. Our findings confirm the hypothesis of prisoners with antisocial personality disorder being a severely traumatized population with serious mental disorders. Traumatic childhood experiences and antisocial personality disorder are associated with criminality variables. This has important implications on preventive treatments as well as on how prison services are addressing these problems.


Assuntos
Transtorno da Personalidade Antissocial/epidemiologia , Transtorno da Personalidade Antissocial/psicologia , Transtornos Mentais/epidemiologia , Transtornos Mentais/psicologia , Prisioneiros/psicologia , Prisioneiros/estatística & dados numéricos , Ferimentos e Lesões/epidemiologia , Ferimentos e Lesões/psicologia , Adolescente , Adulto , Idoso , Criança , Maus-Tratos Infantis/psicologia , Alemanha , Humanos , Delinquência Juvenil/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Adulto Jovem
10.
Biochemistry ; 40(49): 14932-41, 2001 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-11732913

RESUMO

Soluble methane monooxygenase (sMMO) catalyzes the hydroxylation of methane by dioxygen to afford methanol and water, the first step of carbon assimilation in methanotrophic bacteria. This enzyme comprises three protein components: a hydroxylase (MMOH) that contains a dinuclear nonheme iron active site; a reductase (MMOR) that facilitates electron transfer from NADH to the diiron site of MMOH; and a coupling protein (MMOB). MMOR uses a noncovalently bound FAD cofactor and a [2Fe-2S] cluster to mediate electron transfer. The gene encoding MMOR was cloned from Methylococcus capsulatus (Bath) and expressed in Escherichia coli in high yield. Purified recombinant MMOR was indistinguishable from the native protein in all aspects examined, including activity, mass, cofactor content, and EPR spectrum of the [2Fe-2S] cluster. Redox potentials for the FAD and [2Fe-2S] cofactors, determined by reductive titrations in the presence of indicator dyes, are FAD(ox/sq), -176 +/- 7 mV; FAD(sq/hq), -266 +/- 15 mV; and [2Fe-2S](ox/red), -209 +/- 14 mV. The midpoint potentials of MMOR are not altered by the addition of MMOH, MMOB, or both MMOH and MMOB. The reaction of MMOR with NADH was investigated by stopped-flow UV-visible spectroscopy, and the kinetic and spectral properties of intermediates are described. The effects of pH on the redox properties of MMOR are described and exploited in pH jump kinetic studies to measure the rate constant of 130 +/- 17 s(-)(1) for electron transfer between the FAD and [2Fe-2S] cofactors in two-electron-reduced MMOR. The thermodynamic and kinetic parameters determined significantly extend our understanding of the sMMO system.


Assuntos
Transporte de Elétrons/fisiologia , Methylococcus capsulatus/enzimologia , Oxirredutases/metabolismo , Oxigenases/metabolismo , Concentração de Íons de Hidrogênio , Estrutura Molecular , Complexos Multienzimáticos/metabolismo , Oxirredução , Oxirredutases/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
11.
Clin Cardiol ; 24(7): 500-2, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11444640

RESUMO

BACKGROUND: Internal cardioversion of atrial fibrillation with direct current energy has become an increasingly employed technique for patients who fail external cardioversion. HYPOTHESIS: The purpose of this study was to determine whether internal cardioversion could be avoided by careful attention to cardioversion technique in a group of patients referred specifically for internal cardioversion after failed external cardioversion by community cardiologists. METHODS: We performed external cardioversion utilizing two operators applying significant pressure to the thorax with up to 360 J prior to the planned internal cardioversion in 20 patients referred for internal cardioversion after failed attempts at external cardioversion. RESULTS: Sixteen patients (80%) were successfully cardioverted and avoided the risk, inconvenience, and cost of internal cardioversion. CONCLUSION: External cardioversion with significant anterior paddle pressure by two operators can decrease the need for internal cardioversion in a significant portion of patients referred to electrophysiologists for internal cardioversion and should be considered prior to an invasive procedure.


Assuntos
Fibrilação Atrial/terapia , Cardioversão Elétrica/métodos , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Falha de Tratamento
12.
J Electrocardiol ; 34 Suppl: 143-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11781948

RESUMO

We compared the response of endocardial lead systems to radiofrequency (RF) current delivered during atrio-ventricular junction ablation (AVJA) for atrial fibrillation with uncontrolled ventricular rate in 107 patients. The mean age was 67 +/- 11 years and the mean ejection fraction 42 +/- 15%. Patients were divided into 3 groups based on the type of ventricular lead present at the time of ablation: a previously implanted defibrillator lead (group 3, n = 13), a previously implanted pacemaker lead (group 2, n = 46) or a temporary lead (group 1, n = 48), which was subsequently followed by a permanent lead implantation. During AVJA, a median of 5 RF applications (44 +/- 8 W) were given via 4-5-mm electrodes. All but 1 patient had right-sided lesions, while 6 patients also had left sided lesions. Ventricular pacing thresholds were evaluated immediately pre- and post-ablation at 24 hours and at 1 to 3 months. Increases in ventricular pacing voltage thresholds were noted in all 3 groups over time, with the greatest mean increase in group 3 patients: [table: see text]. A greater than 2-fold increase in pacing thresholds was observed only with previously implanted leads, usually within the first 48 hours. It occurred significantly more often in patients with group 3 (6/13 [46%]) compared to group 2 (6/46 [13%], odds ratio 7.6, P = 0.006). A progressive rise in pacing threshold required lead revision in 2/13 group 3 patients (15%) and 2/46 group 2 patients (4%). While RF current has only minor effects on pacing threshold in most patients with previously implanted ventricular lead systems, clinically important alterations requiring device reprogramming or lead revision may occur. Group 3 are significantly more vulnerable to RF current, though the mechanisms are unclear. Group 1 during AVJA, followed by permanent lead implantation appears advisable. Pts with a previously implanted group 3 who require AVJA should be monitored closely.


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter , Desfibriladores Implantáveis , Marca-Passo Artificial , Idoso , Nó Atrioventricular/cirurgia , Estimulação Cardíaca Artificial , Estudos de Casos e Controles , Eletrodos Implantados , Humanos , Radiação , Estudos Retrospectivos , Fatores de Tempo
14.
Radiat Res ; 154(5): 564-81, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11025653

RESUMO

Pulse-height distributions of two constant potential X-ray tubes with fixed anode tungsten targets were measured and unfolded. The measurements employed quantitative alignment of the beam, the use of two different semiconductor detectors (high-purity germanium and cadmium-zinc-telluride), two different ion chamber systems with beam-specific calibration factors, and various filter and tube potential combinations. Monte Carlo response matrices were generated for each detector for unfolding the pulse-height distributions into spectra incident on the detectors. These response matrices were validated for the low error bars assigned to the data. A significant aspect of the validation of spectra, and a detailed characterization of the X-ray tubes, involved measuring filtered and unfiltered beams at multiple tube potentials (30-150 kVp). Full corrections to ion chamber readings were employed to convert normalized fluence spectra into absolute fluence spectra. The characterization of fixed anode pitting and its dominance over exit window plating and/or detector dead layer was determined. An Appendix of tabulated benchmark spectra with assigned error ranges was developed for future reference.


Assuntos
Germânio/química , Tungstênio/química , Benchmarking , Controle de Qualidade , Reprodutibilidade dos Testes , Espectrometria por Raios X , Análise Espectral , Raios X
15.
Gerontologist ; 40(5): 587-95, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11037938

RESUMO

This study examines therapy use and discharge outcomes (community discharge, mortality, or remaining in the facility) over a 90-day period for 1,419 elderly, post-acute care nursing home admissions in South Dakota. Subjects met criteria as rehabilitation candidates (i.e., absence of serious behavioral or medical conditions that would limit rehabilitation potential). Receipt of therapies was related significantly to age (younger), Medicare coverage, hip fracture or stroke diagnosis, absence of cancer diagnosis, and resident or staff expectations for functional improvement. Therapy use was related positively to community discharge and negatively to mortality when controlling for covariates such as age, marital status, payment source, functional status, cognitive status, and major diagnoses. Also, community discharge was related positively to the facility's volume of therapy provision and percentage of Medicare-covered stays.


Assuntos
Serviços de Saúde para Idosos/estatística & dados numéricos , Mortalidade , Casas de Saúde/estatística & dados numéricos , Avaliação de Resultados em Cuidados de Saúde , Alta do Paciente/estatística & dados numéricos , Idoso , Estudos de Coortes , Interpretação Estatística de Dados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
16.
Health Phys ; 79(4): 402-6, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11007462

RESUMO

Two methods for determining ion chamber calibration factors (Nx) are presented for polychromatic tungsten x-ray beams whose spectra differ from beams with known Nx. Both methods take advantage of known x-ray fluence and kerma spectral distributions. In the first method, the x-ray tube potential is unchanged and spectra of differing filtration are measured. A primary standard ion chamber with known Nx for one beam is used to calculate the x-ray fluence spectrum of a second beam. Accurate air energy absorption coefficients are applied to the x-ray fluence spectra of the second beam to calculate actual air kerma and Nx. In the second method, two beams of differing tube potential and filtration with known Nx are used to bracket a beam of unknown Nx. A heuristically derived Nx interpolation scheme based on spectral characteristics of all three beams is described. Both methods are validated. Both methods improve accuracy over the current half value layer Nx estimating technique.


Assuntos
Radiometria/métodos , Tungstênio , Raios X , Alumínio , Calibragem , Radiometria/instrumentação , Reprodutibilidade dos Testes
17.
Circulation ; 101(3): 270-9, 2000 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-10645923

RESUMO

BACKGROUND: Data from experimental models of atrial flutter indicate that macro-reentrant circuits may be confined by anatomic and functional barriers remote from the tricuspid annulus-eustachian ridge atrial isthmus. Data characterizing the various forms of atypical atrial flutter in humans are limited. METHODS AND RESULTS: In 6 of 160 consecutive patients referred for ablation of counterclockwise and/or clockwise typical atrial flutter, an additional atypical atrial flutter was mapped to the right atrial free wall. Five patients had no prior cardiac surgery. Incisional atrial tachycardia was excluded in the remaining patient. High-density electroanatomic maps of the reentrant circuit were obtained in 3 patients. Radiofrequency energy application from a discrete midlateral right atrial central line of conduction block to the inferior vena cava terminated and prevented the reinduction of atypical atrial flutter in each patient. Atrial flutter has not recurred in any patient (follow-up, 18+/-17 months; range, 3 to 40 months). CONCLUSIONS: Atrial flutter can arise in the right atrial free wall. This form of atypical atrial flutter could account for spontaneous or inducible atrial flutter observed in patients referred for ablation and is eliminated with linear ablation directed at the inferolateral right atrium.


Assuntos
Flutter Atrial/etiologia , Idoso , Flutter Atrial/fisiopatologia , Flutter Atrial/cirurgia , Mapeamento Potencial de Superfície Corporal , Ablação por Cateter , Eletrocardiografia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade
18.
J Neurosci ; 20(23): 8771-9, 2000 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11102485

RESUMO

Competition among the several motor axons transiently innervating neonatal muscle fibers results in an increasing disparity in the quantal content and synaptic territory of each competitor, culminating in the permanent loss of all but one axon from neuromuscular junctions. We asked whether differences in the probability of neurotransmitter release also contribute to the increasing disparity in quantal content among competing inputs, and when in the process of competition changes in release probability become apparent. To address these questions, intracellular recordings were made from dually innervated neonatal mouse soleus muscle fibers, and quantal content and paired-pulse facilitation were evaluated for each input. At short interpulse intervals, paired-pulse facilitation was significantly higher for the weaker input with the smaller quantal content than the stronger input with the larger quantal content. Because neurotransmitter release probability across all release sites is inversely related to the extent of facilitation observed after paired-pulse stimulation, this result suggests that release probability is lower for weak compared with strong inputs innervating the same junction. A disparity in the probability of neurotransmitter release thus contributes to the disparity in quantal content that occurs during synaptic competition. Together, this work suggests that an input incapable of sustaining a high release probability may be at a competitive disadvantage for synaptic maintenance.


Assuntos
Junção Neuromuscular/metabolismo , Neurotransmissores/metabolismo , Sinapses/metabolismo , Animais , Animais Recém-Nascidos , Axônios/fisiologia , Cálcio/metabolismo , Estimulação Elétrica , Eletrofisiologia , Técnicas In Vitro , Magnésio/metabolismo , Potenciais da Membrana/fisiologia , Camundongos , Modelos Neurológicos , Neurônios Motores/citologia , Neurônios Motores/metabolismo , Músculo Esquelético/inervação , Junção Neuromuscular/crescimento & desenvolvimento , Análise de Regressão , Transmissão Sináptica/fisiologia
19.
Med Phys ; 27(12): 2680-7, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11190950

RESUMO

The MCNP Monte Carlo radiation transport code was modified for diagnostic medical physics applications. In particular, the modified code was thoroughly benchmarked for the production of polychromatic tungsten x-ray spectra in the 30-150 kV range. Validating the modified code for coupled electron-photon transport with benchmark spectra was supplemented with independent electron-only and photon-only transport benchmarks. Major revisions to the code included the proper treatment of characteristic K x-ray production and scoring, new impact ionization cross sections, and new bremsstrahlung cross sections. Minor revisions included updated photon cross sections, electron-electron bremsstrahlung production, and K x-ray yield. The modified MCNP code is benchmarked to electron backscatter factors, x-ray spectra production, and primary and scatter photon transport.


Assuntos
Método de Monte Carlo , Radiologia/métodos , Tungstênio , Algoritmos , Elétrons , Fótons , Espalhamento de Radiação , Software , Raios X
20.
Med Phys ; 27(12): 2688-92, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11190951

RESUMO

An improved method for an easy, rapid measurement of the intrinsic spatial resolution of a gamma camera is presented. A simplified model was previously developed based solely on mean and standard deviation measurements taken from a region of interest in bar pattern images. This led to an estimate of the modulation transfer function and the full width at half maximum (FWHM) of a line spread function (LSF). The improved method involved expanding the simplified model to incorporate input modulation, square wave input versus the assumed sinusoidal input, aperture (pixel) size, and scatter from the plastic in the bar pattern. The input square wave modulation was calculated to be unity for the typical bar patterns used for gamma camera quality control assessment. For the typical range of bar sizes available, in combination with the typical resolving capabilities of gamma cameras, the sinusoidal approximation of the bar pattern was found to be valid (<1% contribution to the measured resolution from higher harmonic frequencies present in a square wave input with an effective input modulation greater than unity by a factor of 4/pi). The aperture correction factor was calculated for numerous bar and pixel size combinations. Applying the aperture correction factor results in an improvement in the accuracy of the calculated FWHM values, especially for large apertures (pixel sizes). For a camera with a specified FWHM value of 3.5 mm, the simplified model predicts values ranging from 3.2 to 4.1 mm, when the acquisition matrix varies from 128(2) to 512(2). When the expanded model is used with the aperture correction applied, this range was reduced to 3.6-3.9 mm. The scatter correction further improved the calculated FWHM (from 3.6 to 3.8 mm). It is suggested that the expanded model should be used when more accurate measurements are desired, such as in acceptance testing.


Assuntos
Câmaras gama , Radiologia/instrumentação , Radiologia/métodos , Algoritmos , Modelos Estatísticos , Modelos Teóricos , Imagens de Fantasmas , Fótons , Espalhamento de Radiação , Software , Tecnécio/farmacocinética
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