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1.
Brain ; 133(Pt 1): 139-60, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19897544

RESUMO

Magnetic resonance imaging provides evidence for loss of both white and grey matter, in terms of tissue volume, from the cerebral hemispheres after traumatic brain injury. However, quantitative histopathological data are lacking. From the archive of the Department of Neuropathology at Glasgow, the cerebral cortex of 48 patients was investigated using stereology. Patients had survived 3 months after traumatic brain injury and were classified using the Glasgow Outcome Scale as follows: moderately disabled (n = 13), severely disabled (n = 12) and vegetative state (n = 12); and controls. Some patients from the archive were diagnosed with diffuse axonal injury post-mortem. Comparisons of changes in cortical neuron population across Glasgow Outcome Scale groups between diffuse axonal injury and non-diffuse axonal injury patients were undertaken using effect size analyses. The hypotheses tested were that (i) thinning of the cerebral cortex occurred after traumatic brain injury; (ii) changes in thickness of cortical layers in Brodmann areas 11, 10, 24a and 4 differed; and (iii) different changes occurred for neuronal number, their size and nearest neighbour index across Glasgow Outcome Scale groups. There was a greater loss of large pyramidal and large non-pyramidal neurons with a more severe score on the Glasgow Outcome Scale from all four cortical regions, with the greatest loss of neurons from the prefrontal cortex of patients with diffuse axonal injury. There were differences in the changes of number of medium and small pyramidal and non-pyramidal neurons between different cortical regions, and between patients with and without diffuse axonal injury. Generally, a decrease in the somatic diameter of pyramidal and non-pyramidal neurons was associated with a more severe clinical outcome. However, in the motor cortex a more severe Glasgow Outcome Scale was associated with an increased diameter of medium pyramidal neurons and small non-pyramidal cells. Pyramidal and non-pyramidal neurons did not follow a Poisson distribution within the neuropil of control patients. Pyramidal neurons were usually scattered while medium and small non-pyramidal neurons were clustered. An increased spacing between remaining neurons usually occurred across Glasgow Outcome Scale groups. It is concluded that loss of neurons resulted in reduced executive and integrative capability in patients after traumatic head injury.


Assuntos
Lesões Encefálicas/patologia , Córtex Cerebral/patologia , Escala de Resultado de Glasgow/normas , Adolescente , Adulto , Idoso , Lesões Encefálicas/diagnóstico , Contagem de Células/métodos , Contagem de Células/normas , Lesão Axonal Difusa/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto Jovem
2.
Kidney Int Rep ; 6(3): 675-684, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33732982

RESUMO

INTRODUCTION: Chronic kidney disease (CKD) has a prevalence of 9.1% globally, and frequently results in elevated serum phosphate, increasing cardiovascular morbidity and mortality risk in hemodialysis (HD) patients. DS-2330b, an oral NaPi-IIb inhibitor, reduced intestinal phosphate absorption in preclinical studies, but its effect in patients with CKD is unknown. This 2-part, randomized, placebo- and active-controlled, single- and repeated-dose, phase 1b study evaluated safety and efficacy of DS-2330b in patients with CKD on HD. METHODS: Part A, a 2-period, 2-way study, evaluated safety and pharmacokinetics of DS-2330b 250 mg in solution and tablet formulations. Part B assessed the safety of DS-2330b in solution (chosen based on results of part A) and its effect on serum phosphate. Patients were randomized to placebo 3 times daily (TID), DS-2330b 400 mg TID, DS-2330b 400 mg with sevelamer 1.6 g TID, and sevelamer 1.6 g with placebo TID for 14 days. Safety endpoints included adverse event (AE) monitoring. RESULTS: Six patients completed part A. Two patients experienced serious AEs considered unrelated to DS-2330b treatment. Thirty-two patients enrolled and completed part B. Serum phosphate mean change from baseline ± SD was -2.2±1.5 mg/dl versus -1.9 ± 1.1 mg/dl for DS-2330b monotherapy versus placebo. Patients receiving DS-2330b with sevelamer or sevelamer with placebo experienced the greatest serum phosphate decrease from baseline. Nine patients (28.1%) experienced ≥1 treatment-emergent AE (TEAE); 7 patients experienced drug-related TEAEs. The TEAE incidence was comparable between DS-2330b and control groups. CONCLUSIONS: DS-2330b, alone or in combination with sevelamer, was safe and well tolerated but did not demonstrate clinically meaningful efficacy in HD patients.

3.
JOR Spine ; 3(3): e1119, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33015580

RESUMO

OBJECTIVE: The emergence of distraction-based growing rods has provided the means to reduce the progression of spinal deformity in early onset scoliosis (EOS). The current protocols for evaluating spinal implants (ie, ASTM-F1717 and ISO-12189) were developed for fusion/dynamic devices. These protocols do not feature long unsupported rod lengths subjected to distraction. Due to the unsuitability of the existing guidelines for the evaluation of growing rods, a new distraction-based finite element protocol is presented herein for the first time. METHOD: A vertebrectomy (VO) model from current protocols was modified to accommodate multi-spinal segments (ie, MS model) in which springs with appropriate stiffness were simulated in between the plastic blocks. To assess the efficacy of the protocol, two different computational studies were conducted: (a) compression-bending (MS-CB) with no distraction, and (b) distraction followed by compression-bending (MS-D + CB). In each study, the model with no axial connector (rods-only) was modified to include a) 80-mm long tandem (LT) connectors, and b) side-by-side (SBS) connectors. Stiffness and yield loads were calculated as per ASTM-F1717 guidelines and compared with the corresponding VO models with no distraction. In the MS-D + CB models, distraction was applied at the top block, stretching the spring-block construct in a simulation of scoliosis surgery prior to locking the construct at the connector-rods' interface. RESULTS: MS-CB models predicted higher stiffness and yield loads, compared to the VO models. The locking mechanism produced pre-existing stresses on the rod-connector interface, which caused a shift in the location of high-stress regions to the distraction site. Distraction led to a decrease in the construct's stiffness and yield load. DISCUSSION: The proposed protocol enables the simulation of clinical parameters that are not feasible in the F1717 models and predicted stress patterns in the hardware consistent with observed clinical failures.

4.
J Cataract Refract Surg ; 34(11): 1855-61, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19006730

RESUMO

PURPOSE: To demonstrate the value, from the patient's perspective, of an apodized, diffractive, presbyopia-correcting multifocal intraocular lens (MF-IOL) compared to a conventional monofocal intraocular lens (CM-IOL). SETTING: Open-label, multi-site U.S. clinical trial. METHODS: A cost-benefit analysis was conducted using cataract patients' willingness-to-pay (WTP) for spectacle independence as the measure of economic benefit. WTP was elicited from participants in a clinical trial comparing a MF-IOL and a CM-IOL. Costs borne by patients were obtained from standard reference sources. A 14-year analytical timeframe was used, and a 3% annual discount rate was applied to both costs and benefits. The outcome of interest was net benefit (difference between benefits and costs). A probabilistic sensitivity analysis was used to confirm the robustness of the economic results. RESULTS: Four hundred ninety-five patients provided WTP estimates for spectacle independence (MF-IOL, n = 339; CM-IOL, n = 156). Eighty percent of all patients were willing to pay at least $5 per day to be spectacle independent. The incremental acquisition cost associated with bilateral implantation of 2 MF-IOLs was estimated at $4,000. Eighty percent in the MF-IOL group and 8% in the CM-IOL group reported post-operative spectacle independence. The net benefit was $11,670 in the MF-IOL group and $155 in the CM-IOL group. The probabilistic sensitivity analysis confirmed the robustness of the economic outcomes. CONCLUSION: The net benefit of the MF-IOL exceeded its acquisition cost and the net benefit of the CM-IOL, demonstrating its value to select cataract patients willing to pay a premium for spectacle independence.


Assuntos
Efeitos Psicossociais da Doença , Financiamento Pessoal , Lentes Intraoculares/economia , Presbiopia/economia , Idoso , Análise Custo-Benefício , Feminino , Humanos , Implante de Lente Intraocular , Masculino , Presbiopia/cirurgia , Qualidade de Vida , Estados Unidos
5.
Prog Brain Res ; 161: 263-91, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17618984

RESUMO

Minor traumatic brain injury (mTBI) is caused by inertial effects, which induce sudden rotation and acceleration forces to and within the brain. At less severe levels of injury, for example in mTBI, there is probably only transient disturbance of ionic homeostasis with short-term, temporary disturbance of brain function. With increased levels of severity, however, studies in animal models of TBI and in humans have demonstrated focal intra-axonal alterations within the subaxolemmal, neurofilament and microtubular cytoskeletal network together with impairment of axoplasmic transport. These changes have, until very recently, been thought to lead to progressive axonal swelling, axonal detachment or even cell death over a period of hours or days, the so-called process of "secondary axotomy". However, recent evidence has suggested that there may be two discrete pathologies that may develop in injured nerve fibers. In the TBI scenario, disturbances of ionic homeostasis, acute metabolic changes and alterations in cerebral blood flow compromise the ability of neurons to function and render cells of the brain increasingly vulnerable to the development of pathology. In ice hockey, current return-to-play guidelines do not take into account these new findings appropriately, for example allow returning to play in the same game. It has recently been hypothesized that the processes summarized above may predispose brain cells to assume a vulnerable state for an unknown period after mild injury (mTBI). Therefore, we recommend that any confused player with or without amnesia should be taken off the ice and not be permitted to play again for at least 72h.


Assuntos
Traumatismos em Atletas/complicações , Traumatismos em Atletas/patologia , Lesões Encefálicas/complicações , Lesões Encefálicas/patologia , Doenças do Sistema Nervoso/etiologia , Doenças do Sistema Nervoso/patologia , Animais , Traumatismos em Atletas/epidemiologia , Biomarcadores , Lesões Encefálicas/epidemiologia , Humanos , Doenças do Sistema Nervoso/epidemiologia , Doenças do Sistema Nervoso/prevenção & controle
6.
J Neuropathol Exp Neurol ; 65(5): 478-88, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16772871

RESUMO

Paraffin-embedded blocks from the thalamus of 9 control patients, 9 moderately disabled, 12 severely disabled, and 10 vegetative head-injured patients assessed using the Glasgow Outcome Scale and identified from the Department of Neuropathology archive. Neurons, astrocytes, macrophages, and activated microglia were differentiated by Luxol fast blue/cresyl violet, GFAP, CD68, and CR3/43 staining and stereological techniques used to estimate cell number in a 28-microm-thick coronal section. Counts were made in subnuclei of the mediodorsal, lateral posterior, and ventral posterior nuclei, the intralaminar nuclei, and the related internal lamina. Neuronal loss occurred from mediodorsal parvocellularis, rostral center medial, central lateral and paracentral nuclei in moderately disabled patients; and from mediodorsal magnocellularis, caudal center medial, rhomboid, and parafascicular nuclei in severely disabled patients; and all of the above and the centre median nucleus in vegetative patients. Neuronal loss occurred primarily from cognitive and executive function nuclei, a lesser loss from somatosensory nuclei and the least loss from limbic motor nuclei. There was an increase in the number of reactive astrocytes, activated microglia, and macrophages with increasing severity of injury. The study provides novel quantitative evidence for differential neuronal loss, with survival after human head injury, from thalamic nuclei associated with different aspects of cortical activation.


Assuntos
Traumatismos Cranianos Fechados/patologia , Núcleos Talâmicos/patologia , Adolescente , Adulto , Análise de Variância , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Contagem de Células , Distribuição de Qui-Quadrado , Estudos Transversais , Avaliação da Deficiência , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Traumatismos Cranianos Fechados/classificação , Traumatismos Cranianos Fechados/metabolismo , Humanos , Imuno-Histoquímica/métodos , Antígeno de Macrófago 1/metabolismo , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Neurônios/patologia , Núcleos Talâmicos/metabolismo
7.
Nat Commun ; 7: 13294, 2016 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-27827358

RESUMO

Pre-surgical studies allow study of the relationship between mutations and response of oestrogen receptor-positive (ER+) breast cancer to aromatase inhibitors (AIs) but have been limited to small biopsies. Here in phase I of this study, we perform exome sequencing on baseline, surgical core-cuts and blood from 60 patients (40 AI treated, 20 controls). In poor responders (based on Ki67 change), we find significantly more somatic mutations than good responders. Subclones exclusive to baseline or surgical cores occur in ∼30% of tumours. In phase II, we combine targeted sequencing on another 28 treated patients with phase I. We find six genes frequently mutated: PIK3CA, TP53, CDH1, MLL3, ABCA13 and FLG with 71% concordance between paired cores. TP53 mutations are associated with poor response. We conclude that multiple biopsies are essential for confident mutational profiling of ER+ breast cancer and TP53 mutations are associated with resistance to oestrogen deprivation therapy.


Assuntos
Antineoplásicos/farmacologia , Inibidores da Aromatase/farmacologia , Neoplasias da Mama/genética , Resistencia a Medicamentos Antineoplásicos/genética , Proteína Supressora de Tumor p53/genética , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/uso terapêutico , Inibidores da Aromatase/uso terapêutico , Biópsia/métodos , Mama/patologia , Neoplasias da Mama/sangue , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Análise Mutacional de DNA/métodos , Estrogênios/metabolismo , Feminino , Proteínas Filagrinas , Humanos , Antígeno Ki-67/análise , Pessoa de Meia-Idade , Mutação , Receptores de Estrogênio/metabolismo , Resultado do Tratamento , Sequenciamento do Exoma/métodos
8.
J Neurotrauma ; 22(8): 873-84, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16083354

RESUMO

It was hypothesized that rapid rather than slow re-warming following traumatic brain injury (TBI) and short-term hypothermia results in secondary, ultrastructural pathology. After stretch injury to the right optic nerve, adult guinea pigs were randomly allocated to one of six experimental groups. Either (1) sham (all procedures but not stretch-injured; n = 4); injured and (2) maintained at normal temporalis core temperature (38.5 degrees C) for 8 hours (n = 6); (3) cooled rapidly to 32.5 degrees C (temporalis temperature), maintained for 4 h and re-warmed to 38.5 degrees C at 1 degrees C rise every 10 min (fast; n = 6); (4) cooled and re-warmed at 1 degrees C rise every 20 min (medium; n = 6); (5) cooled and rewarmed at 1 degrees C rise every 40 min (slow; n = 6) before being killed 8 h after injury; and (6) uninjured animals (n = 6) cooled to 32.5 degrees C for 4 h and then re-warmed at 1 degrees C every 10 min before killing 4 h later. Tissue was processed for light immunocytochemistry (beta-APP and RMO-14) and ultrastructural stereology. In both uninjured and injured fast re-warmed animals, there was almost total loss of axonal microtubules (MT) and an increased number of neurofilaments (NF) within the axoplasm. In the former, there was also compaction of NF. The number of MT was reduced to 40% of control values, NFs were increased but were not compacted after medium rate re-warming. Following slow re-warming the axonal cytoskeleton did not differ from that in control animals. It is concluded that re-warming faster than 1 degrees C every 40 min following mild post-traumatic hypothermia induces secondary axonal pathology.


Assuntos
Temperatura Corporal/fisiologia , Lesões Encefálicas/terapia , Hipotermia Induzida/métodos , Degeneração Neural/prevenção & controle , Traumatismos do Nervo Óptico/terapia , Citoesqueleto de Actina/patologia , Citoesqueleto de Actina/ultraestrutura , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Axônios/patologia , Axônios/ultraestrutura , Biomarcadores , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Modelos Animais de Doenças , Cobaias , Imuno-Histoquímica , Masculino , Microscopia Eletrônica de Transmissão , Microtúbulos/patologia , Microtúbulos/ultraestrutura , Degeneração Neural/patologia , Degeneração Neural/fisiopatologia , Nervo Óptico/patologia , Nervo Óptico/fisiopatologia , Nervo Óptico/ultraestrutura , Traumatismos do Nervo Óptico/patologia , Traumatismos do Nervo Óptico/fisiopatologia , Fatores de Tempo
9.
Brain ; 127(Pt 11): 2470-8, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15456707

RESUMO

In vivo imaging techniques have indicated for many years that there is loss of white matter after human traumatic brain injury (TBI) and that the loss is inversely related to cognitive outcome. However, correlated, quantitative evidence for loss of neurons from either the cerebral cortex or the diencephalon is largely lacking. There is some evidence in models of TBI that neuronal loss occurs within the thalamus, but no systematic studies of such loss have been undertaken in the thalamus of humans after blunt head injury. We have undertaken a stereological analysis of changes in numbers of neurons within the dorsomedial, ventral posterior and lateral posterior thalamic nuclei in patients assessed by the Glasgow Outcome Scale as moderately disabled (n = 9), severely disabled (n = 12) and vegetative (n = 10) head-injured patients who survived between 6 h and 3 years, and controls (n = 9). In histological sections at the level of the lateral geniculate body, the cross-sectional area of each nucleus and the number and the mean size of neurons within each nucleus was quantified. A statistically significant loss of cross-sectional area and number of neurons occurred in the dorsomedial nucleus in moderately disabled, and both the dorsomedial and ventral posterior thalamic nuclei in severely disabled and vegetative head-injured patients. However, there was no change in neuronal cell size. In the lateral posterior nucleus, despite a reduction in mean cell size, there was not a significant change in either nuclear area or number of neurons in cases of moderately disabled, severely disabled or vegetative patients. We posit, although detailed neuropsychological outcome for the patients included within this study was not available, that neuronal loss in the dorsomedial thalamus in moderately and severely disabled and vegetative patients may be the structural basis for the clinical assessment in the Glasgow Outcome Scale. In severely disabled and vegetative patients, loss of neurons from the ventral posterior thalamic nucleus may also reflect loss of response to afferent stimuli.


Assuntos
Traumatismos Cranianos Fechados/patologia , Núcleos Talâmicos/patologia , Adolescente , Adulto , Idoso , Avaliação da Deficiência , Feminino , Escala de Resultado de Glasgow , Humanos , Núcleos Laterais do Tálamo/patologia , Masculino , Núcleo Mediodorsal do Tálamo/patologia , Pessoa de Meia-Idade , Neurônios/patologia , Estado Vegetativo Persistente/patologia , Núcleos Ventrais do Tálamo/patologia
11.
Theriogenology ; 63(2): 615-24, 2005 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-15626420

RESUMO

It is estimated that as many as 30,000 offspring, mostly cattle, have been produced in the past 5 years using AI or some other means of transport with spermatozoa sexed by flow cytometric sperm sorting and DNA as the marker of differentiation. It is well documented that the only marker in sperm that can be effectively used for the separation of X- and Y-chromosome bearing spermatozoa is DNA. The method, as it is currently used worldwide, is commonly known as the Beltsville Sperm Sexing Technology. The method is based on the separation of sperm using flow cytometric sorting to sort fluorescently (Hoechst 33342) labeled sperm based on their relative content of DNA within each population of X- and Y-spermatozoa. Currently, sperm can be produced routinely at a rate of 15 million X- and an equal number of Y-sperm per hour. The technology is being applied in livestock, laboratory animals, and zoo animals; and in humans with a success rate of 90-95% in shifting the sex ratio of offspring. Delivery of sexed sperm to the site of fertilization varies with species. Conventional AI, intrauterine insemination, intra-tubal insemination, IVF with embryo transfer and deep intrauterine insemination are effectively used to obtain pregnancies dependent on species. Although sperm of all species can be sorted with high purity, achieving pregnancies with the low numbers of sperm needed for commercial application remains particularly elusive in swine. Deep intrauterine insemination with 50-100 million sexed boar sperm per AI has given encouragement to the view that insemination with one-fiftieth of the standard insemination number will be sufficient to achieve pregnancies with sexed sperm when specialized catheters are used. Catheter design, volume of inseminate, number of sexed sperm are areas where further development is needed before routine inseminations with sexed sperm can be conducted in swine. Cryopreservation of sex-sorted sperm has been routinely applied in cattle. Although piglets have been born from frozen sex-sorted boar sperm, freezing and processing protocols in combination with sex-sorted sperm are not yet optimal for routine use. This review will discuss the most recent results and advances in sex-sorting swine sperm with emphasis on what developments must take place for the sexing technology to be applied in commercial practice.


Assuntos
Pré-Seleção do Sexo/veterinária , Suínos , Animais , Separação Celular/métodos , Separação Celular/veterinária , Criopreservação/veterinária , Feminino , Masculino , Técnicas Reprodutivas/veterinária , Preservação do Sêmen/veterinária , Pré-Seleção do Sexo/métodos , Espermatozoides/ultraestrutura , Cromossomo X , Cromossomo Y
12.
J Neurotrauma ; 32(11): 780-90, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25333317

RESUMO

Patients with chronic traumatic encephalopathy (CTE) show loss of central white matter, central gray matter, and cortical gray matter with increasing post-traumatic survival. The majority of experimental studies using animals have, however, discussed only the ultrastructural pathophysiology of injured central white matter leading to secondary axotomy and the formation of axonal terminal bulbs. Using the stretch-injured optic nerve model in adult guinea pigs, the present study provides novel quantitative data concerning Wallerian degeneration of disconnected axonal fragments following secondary axotomy out to 12 weeks after injury to an optic nerve. The time course of Wallerian degeneration at the level of an individual nerve fiber is comparable to that reported in earlier studies over 48 h to two weeks after secondary axotomy. But only a relatively small proportion of nerve fibers within the optic tract degenerate via Wallerian degeneration during the first two weeks. Rather, examples of each of the three stages of Wallerian degeneration-acute axonal degeneration, latency of the distal axonal segment, and granular fragmentation-occur within the optic tract across the entire experimental survival of 12 weeks used in the present study. This data suggests that some nerve fibers initiate Wallerian degeneration days and weeks after the initial time of mechanical injury to an optic nerve. The number of intact nerve fibers continues to fall over at least three months after injury in the stretch-injury model of traumatic axonal injury. It is suggested that these novel findings relate to the mechanism(s) whereby central white matter volume decreases over months and years in CTE patients.


Assuntos
Lesões Encefálicas/patologia , Modelos Animais de Doenças , Traumatismos do Nervo Óptico/patologia , Técnicas Estereotáxicas , Estresse Mecânico , Degeneração Walleriana/patologia , Animais , Cobaias , Masculino
13.
J Neurotrauma ; 20(2): 151-68, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12675969

RESUMO

All previous analyses of axonal responses to traumatic axonal injury (TAI) have described the ultrastructure of changes in the cytoskeleton and axolemma within 6 h of injury. In the present study we tested the hypothesis that there are, in addition, ultrastructural pathological changes up to 1 week after injury. TAI was induced in the adult guinea pig optic nerve of nine animals. Three animals were killed at either 4 h, 24 h, or 7 days (d) after injury. Quantitative analysis of the number or proportion of axons within 0.5-micro m-wide bins showed an increase in the number of axons with a diameter of less than 0.5 micro m at 4 h, 24 h, and 7 d, the presence of lucent axons at 24 h and 7 d and that the highest number of injured axons occurred about half way along the length of the nerve. A spectrum of pathological changes occurred in injured fibers-pathology of mitochondria; dissociation of myelin lamellae but little damage to the axon; loss of linear register of the axonal cytoskeleton; differential responses between microtubules (MT) and neurofilaments (NF) in different sizes of axon; two different sites of compaction of NF; loss of both NF (with an increase in their spacing) and MT (with a reduction in their spacing); replacement of the axoplasm by a flocculent precipitate; and an increased length of the nodal gap. These provide the first ultrastructural evidence for Wallerian degeneration of nerve fibers in an animal model of TAI.


Assuntos
Axônios/ultraestrutura , Citoesqueleto/ultraestrutura , Traumatismos do Nervo Óptico/patologia , Animais , Cobaias , Masculino , Fibras Nervosas/patologia , Valores de Referência , Degeneração Walleriana/patologia
14.
J Bone Joint Surg Am ; 96(4): e31, 2014 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-24553900

RESUMO

BACKGROUND: An investigation was conducted to establish the hospital-wide prevalence of cast saw injuries and to identify variables that put patients at increased risk, with the goal of reducing the injury rate. METHODS: Information was collected from January 2010 through December 2012 on all patients who had a cast removed or cut at our institution. Locations included the operating suites, emergency department, ambulatory clinics, and hospital floors. A cast cutting log was used to capture the total number of casts cut. An adverse event form was used to document each injury. A continuous quality improvement approach was used throughout the study period to implement incremental improvements to our program. Changes included an education and certification program on cast saw use for all providers, a protocol for a plastic surgery consultation, and a cast saw blade inspection protocol with maintenance logs. RESULTS: Twenty-nine injuries occurred in 23,615 cast cuttings over the three years, for an overall rate of 1.23 (95% confidence interval [CI], 0.86 to 1.76) per 1000. A minor decrease in cast saw injuries was recorded over the course of the study (eleven of 8043 [1.37 per 1000] in 2010, ten of 7885 [1.27 per 1000] in 2011, and eight of 7687 [1.04 per 1000] in 2012), but the decrease was not significant (p = 0.87). The emergency department had the highest rate of cast saw injuries (p < 0.0001), with a significantly greater rate during the night compared with the day (eleven of 1293 [8.51 per 1000] compared with fifteen of 19,419 [0.77 per 1000], respectively; p < 0.0001). The injuries were all minor. Key risk factors for a cast saw injury included provider inexperience, patient sedation, and poor cast saw blade condition. CONCLUSIONS: The rate of cast saw injuries in a busy pediatric orthopaedic department was small, but a considerably increased risk existed for those patients cared for in the emergency department by orthopaedic residents. Improving education and training in cast saw use has the potential to decrease the prevalence of cast saw injuries over time.


Assuntos
Moldes Cirúrgicos/efeitos adversos , Complicações Intraoperatórias/epidemiologia , Complicações Intraoperatórias/prevenção & controle , Instrumentos Cirúrgicos/efeitos adversos , Competência Clínica , Serviço Hospitalar de Emergência , Humanos , Incidência , Prevalência , Melhoria de Qualidade , Fatores de Risco
15.
Brain Sci ; 3(3): 1374-94, 2013 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-24961533

RESUMO

There is increasing evidence in the experimental and clinical traumatic brain injury (TBI) literature that loss of central myelinated nerve fibers continues over the chronic post-traumatic phase after injury. However, the biomechanism(s) of continued loss of axons is obscure. Stretch-injury to optic nerve fibers in adult guinea-pigs was used to test the hypothesis that damage to the myelin sheath and oligodendrocytes of the optic nerve fibers may contribute to, or facilitate, the continuance of axonal loss. Myelin dislocations occur within internodal myelin of larger axons within 1-2 h of TBI. The myelin dislocations contain elevated levels of free calcium. The volume of myelin dislocations increase with greater survival and are associated with disruption of the axonal cytoskeleton leading to secondary axotomy. Waves of Ca2+ depolarization or spreading depression extend from the initial locus injury for perhaps hundreds of microns after TBI. As astrocytes and oligodendrocytes are connected via gap junctions, it is hypothesized that spreading depression results in depolarization of central glia, disrupt axonal ionic homeostasis, injure axonal mitochondria and allow the onset of axonal degeneration throughout an increasing volume of brain tissue; and contribute toward post-traumatic continued loss of white matter.

17.
Int J Dev Neurosci ; 30(3): 167-83, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22212603

RESUMO

In the middle of the last century it had been thought that a good recovery of function and behavior would occur after traumatic brain injury (TBI) in very young human beings. A recent major change in thinking states that early childhood TBI may result in a severe compromise of normal brain growth and development such that TBI, rather, may compromise later normal development resulting in a need for very long term patient care and management. The mechanisms of injury and pathology within the injured brain are reviewed and compared between when injury occurs at or close to the time of birth, in an infant, in a young child, in a child between ages 5 and 10, in young and older adolescents and in young adulthood. Our understanding of pathophysiological responses by cells of the human central nervous system has recently greatly increased but has really only served to illustrate the great complexity of interactions between different types of cell within the growing and developing CNS. The hypothesis is developed that the outcome for a very young patient differs with the relative state of development of injured cells at the locus of injury. And that the potential for either repair, re-instatement of normal cellular and organ function or for continued normal development is much reduced after an early brain insult (EBI) compared with TBI in a slightly older child or young adult patient. The advent of increasingly sophisticated non-invasive imaging technology has allowed assessment of the influence and time course of brain pathology both early and late after TBI. This has generated greater confidence on the part of clinicians in forecasting outcomes for an injured patient. But our increased understanding has still not allowed development of therapeutic strategies that might ameliorate the effect of an injury. It is suggested that an improved integration of major clinical and scientific effort needs to be made to appreciate the import of multiple interactions between cells forming the neurovascular unit in order to improve any potential for post-traumatic recovery after TBI in neonates and young children.


Assuntos
Envelhecimento/patologia , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Adolescente , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido
18.
Brain Imaging Behav ; 6(2): 108-36, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22434552

RESUMO

Neuroimaging identified abnormalities associated with traumatic brain injury (TBI) are but gross indicators that reflect underlying trauma-induced neuropathology at the cellular level. This review examines how cellular pathology relates to neuroimaging findings with the objective of more closely relating how neuroimaging findings reveal underlying neuropathology. Throughout this review an attempt will be made to relate what is directly known from post-mortem microscopic and gross anatomical studies of TBI of all severity levels to the types of lesions and abnormalities observed in contemporary neuroimaging of TBI, with an emphasis on mild traumatic brain injury (mTBI). However, it is impossible to discuss the neuropathology of mTBI without discussing what occurs with more severe injury and viewing pathological changes on some continuum from the mildest to the most severe. Historical milestones in understanding the neuropathology of mTBI are reviewed along with implications for future directions in the examination of neuroimaging and neuropathological correlates of TBI.


Assuntos
Lesões Encefálicas/diagnóstico , Encéfalo/patologia , Neuroimagem/métodos , Humanos
19.
NeuroRehabilitation ; 28(2): 63-74, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21447905

RESUMO

Neuroimaging at all stages of a traumatic brain injury (TBI) provides information about gross brain pathology. In this review, post-mortem TBI cases are matched to neuroimaging findings from TBI survivors to demonstrate the close correlation between observable pathology with in vivo neuroimaging to the underlying neuropathology. An emphasis of this review focuses on neuroimaging identification of trauma induced cortical and white matter degeneration along with hydrocephalus ex vacuo expansion of the ventricular system as the injured brain exhibits atrophic changes. The role of hippocampal atrophy and thalamic injury along with the vulnerability of the corpus callosum in TBI are also reviewed. The aim of this review is to provide pathological confirmation of observable neuroimaging abnormalities that relate directly to trauma-induced effects of the injury.


Assuntos
Lesões Encefálicas/diagnóstico , Mapeamento Encefálico , Encéfalo/patologia , Diagnóstico por Imagem/métodos , Encéfalo/fisiopatologia , Lesões Encefálicas/fisiopatologia , Humanos
20.
Indian J Surg ; 73(5): 363-5, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23024543

RESUMO

Primary Osteosarcoma of the breast is an aggressive and relatively rare tumour whose prognosis is very poor.It is often a diagnostic dilemma to the pathologists and the surgeons are perplexed due to its aggressive behaviour as its pathology and prognostic factors are unclear. Due to its rarity we suggest pooling of tissue samples from various centres in biobanks for future studies (including molecular biological studies) so that its behaviour can be better understood.

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