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1.
Epidemiol Infect ; 145(14): 2980-2990, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28903784

RESUMEN

Each year in the United States, an estimated 525 000 infections, 2900 hospitalizations, and 82 deaths are attributed to consumption of pork. We analyzed the epidemiology of outbreaks attributed to pork in the United States reported to the Centers for Disease Control and Prevention (CDC) 1998-2015. During that period, 288 outbreaks were attributed to pork, resulting in 6372 illnesses, 443 hospitalizations, and four deaths. The frequency of outbreaks attributed to pork decreased by 37% during this period, consistent with a decline in total foodborne outbreaks. However, outbreaks attributed to pork increased by 73% in 2015 (19 outbreaks) compared with the previous 3 years (average of 11 outbreaks per year), without a similar increase in total foodborne outbreaks. Most (>99%) of these outbreaks occurred among people exposed in the same state. The most frequent etiology shifted from Staphylococcus aureus toxin during 1998-2001 (19%) to Salmonella during 2012-2015 (46%). Outbreaks associated with ham decreased from eight outbreaks per year during 1998-2001, to one per year during 2012-2015 (P < 0·01). Additional efforts are necessary to reduce outbreaks and sporadic illnesses associated with pork products.


Asunto(s)
Brotes de Enfermedades , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos/epidemiología , Carne Roja/microbiología , Animales , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/mortalidad , Incidencia , Sus scrofa , Estados Unidos/epidemiología
2.
J Chem Phys ; 146(19): 194501, 2017 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-28527447

RESUMEN

In a recent paper [C. E. Bertrand et al., J. Chem. Phys. 145, 014502 (2016)], we have shown that the collective dynamics of methanol shows a fast relaxation process related to the standard density-fluctuation heat mode and a slow non-Fickian mode originating from the hydrogen bonded molecular associates. Here we report on the length scale dependence of this slow relaxation process. Using quasielastic neutron scattering and molecular dynamics simulations, we show that the dynamics of the slow process is affected by the structuring of the associates, which is accessible through polarized neutron diffraction experiments. Using a series of partially deuterated samples, the dynamics of the associates is investigated and is found to have a similar time scale to the lifetime of hydrogen bonding in the system. Both the structural relaxation and the dynamics of the associates are thermally activated by the breaking of hydrogen bonding.

3.
J Chem Phys ; 145(1): 014502, 2016 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-27394112

RESUMEN

Quasielastic neutron scattering measurements and molecular dynamics simulations were combined to investigate the collective dynamics of deuterated methanol, CD3OD. In the experimentally determined dynamic structure factor, a slow, non-Fickian mode was observed in addition to the standard density-fluctuation heat mode. The simulation results indicate that the slow dynamical process originates from the hydrogen bonding of methanol molecules. The qualitative behavior of this mode is similar to the previously observed α-relaxation in supercooled water [M. C. Bellissent-Funel et al., Phys. Rev. Lett. 85, 3644 (2000)] which also originates from the formation and dissolution of hydrogen-bonded associates (supramolecular clusters). In methanol, however, this mode is distinguishable well above the freezing transition. This finding indicates that an emergent slow mode is not unique to supercooled water, but may instead be a general feature of hydrogen-bonding liquids and associating molecular liquids.

5.
Int J Tuberc Lung Dis ; 28(5): 231-236, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38659143

RESUMEN

BACKGROUNDCulture-based diagnostics are the gold standard for diagnosing pulmonary TB (PTB). We characterized culture practices by comparing cases with documented sputum culture to those without.METHODSUsing multivariable logistic regression, we examined associations between PTB case characteristics and no documented sputum culture reported to the U.S. National TB Surveillance System during 2011-2021.RESULTSAmong 69,538 PTB cases analyzed, no sputum culture attempt was documented for 5,869 (8%). Non-sputum culture specimens were documented for 54%, 80%, and 89% of cases without documented sputum culture attempts among persons aged <15 years, 15-64, and 65+ years, respectively; bronchial fluid and lung tissue were common non-sputum specimens among cases in persons >15 years old. Having no documented sputum culture was associated with age <15 years (aOR 23.84, 99% CI 20.09-28.27) or ≥65 years (aOR 1.22, 99% CI 1.07-1.39), culture of a non-sputum specimen (aOR 6.57, 99% CI 5.93-7.28), residence in a long-term care facility (aOR 1.58, 99% CI 1.23-2.01), and receiving TB care outside of a health department (aOR 1.79, 99% CI 1.61-1.98).CONCLUSIONSInability to obtain sputum from children and higher diagnostic suspicion for disease processes that require tissue-based diagnostics could explain these findings..


Asunto(s)
Esputo , Tuberculosis Pulmonar , Humanos , Esputo/microbiología , Estados Unidos , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/microbiología , Adolescente , Masculino , Persona de Mediana Edad , Adulto , Adulto Joven , Femenino , Anciano , Niño , Preescolar , Lactante , Modelos Logísticos , Mycobacterium tuberculosis/aislamiento & purificación
6.
Eye (Lond) ; 37(10): 2089-2094, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36316557

RESUMEN

BACKGROUND: The COVID-19 pandemic has impacted negatively on many areas of biomedical research and there is concern that academic recovery will take several years. This survey aimed to define the impact of the COVID-19 pandemic on UK ophthalmologists' research activities and understand the implications for recovery. METHODS: An online survey comprising multiple choice and free-text questions was designed, piloted and then distributed to Royal College of Ophthalmologists (RCOphth) members in January 2021. Respondent characteristics, research expectations and experiences through the pandemic were captured. Descriptive and comparative statistics were applied to quantitative data alongside content analysis of qualitative data. RESULTS: In total, 148 respondents (3.7% of RCOphth membership) comprised 46 trainees (31.1%), 97 consultants (65.5%) and 5 SAS doctors (3.4%); 54 had clinical-academic roles (36.5%) and 65/94 (69.1%) ophthalmologists with fully clinical posts identified as research-active. Of 114 research-active respondents, 104 (91.2%) reported an impact on their research from COVID-19; negative impacts included loss of research time (n = 69), research delays (n = 96) and funding shortfalls (n = 63). Content analysis identified five common themes; type of research activity, clinical demands, institutional challenges, COVID-19 alignment and work-life balance. CONCLUSIONS: UK ophthalmology research has been adversely impacted by the pandemic. A substantial proportion of UK ophthalmologists are research active, but 20.4% of those surveyed felt that the pandemic had made research less attractive. Strategic steps must be taken to nurture UK ophthalmologists' engagement with research, especially for those who currently do no research, if the profession is to align itself with the Government vision of 'Research for All'.


Asunto(s)
Investigación Biomédica , COVID-19 , Oftalmólogos , Humanos , COVID-19/epidemiología , Pandemias , Encuestas y Cuestionarios , Reino Unido/epidemiología
7.
Strabismus ; 31(1): 26-30, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36529745

RESUMEN

BACKGROUND: Acute acquired concomitant esotropia (AACE) is usually a benign form of strabismus that infrequently is associated with intracranial pathology. Clinicians have noted an increase in its incidence and theorize that it may be related to public health "lockdown" measures taken in response to the COVID-19 pandemic. With an increased incidence of AACE clinicians must firstly differentiate AACE from common accommodative esotropia and secondly recognize AACE as a possible sign of serious neuropathology.Diffuse Intrinsic Pontine Glioma (DIPG) is a devastating diagnosis for affected families. Children typically present at age 6-7 years with cranial nerve palsies, long tract signs, and/or cerebellar signs. Diagnosis is made from characteristic findings on magnetic resonance brain imaging (MRI brain) and treatment includes radiotherapy and palliative care. Two years from diagnosis, 90% of affected children will have died from their disease. CASE SERIES: We present four cases that attended our pediatric ophthalmology clinic with AACE either as a presenting sign of DIPG or as a clinical finding following a DIPG diagnosis. Patient A (age 5 years) presented to the emergency eye clinic with sudden onset diplopia and intermittent esotropia. Suppression later developed, they had 0.00 logMAR visual acuity either eye, and bilateral physiological hypermetropia. MRI brain imaging requested as a result of the unusual presentation led to the DIPG diagnosis. The other 3 cases (ages 11, 5 & 5 years) were assessed post DIPG diagnosis and found to have an esotropia measuring bigger on 1/3-meter fixation than 6-meter fixation, full ocular motility, physiological hypermetropia or emmetropia, and visual acuity normal for age. Other than patient B (age 11 years), who had papilledema and gaze evoked nystagmus when they were assessed 2 weeks prior to death, no patient had any other clinical eye findings. CONCLUSIONS: This small series of 4 patients attending our clinic within a 12-month period supports the notion that children presenting with AACE should routinely be offered brain MRI. Not all children with DIPG-associated AACE have significant ophthalmic findings indicative of intracranial pathology. With the potential for increased incidence of AACE related to lockdowns, clinicians should be reminded of the infrequent possibility their patient has a more serious condition.


Asunto(s)
COVID-19 , Glioma Pontino Intrínseco Difuso , Esotropía , Hiperopía , Estrabismo , Niño , Humanos , Preescolar , Esotropía/diagnóstico , Esotropía/etiología , Esotropía/cirugía , Glioma Pontino Intrínseco Difuso/complicaciones , Pandemias , COVID-19/complicaciones , Control de Enfermedades Transmisibles , Estrabismo/complicaciones , Enfermedad Aguda , Estudios Retrospectivos
9.
Curr Eye Res ; 45(6): 713-717, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-31876191

RESUMEN

Background: Nystagmus is a disorder of rhythmic, involuntary oscillations of the eyes and can be classified as either infantile or acquired. Whether it occurs in isolation or as a part of other visual or neurological disorders, it causes significant visual dysfunction and problems with social functioning. In this study, we seek to understand ways in which people with nystagmus are currently supported across the UK and identify any geographical variations or disconnects between current practice and best practice, as judged by patients and their carers.Methods: A nationwide, qualitative, cross-sectional, questionnaire study of people with nystagmus and their carers. Recruitment was achieved through specialist clinics, charity events, online advertisements and social media calls. Data was gathered using five, age-appropriate questionnaires which were completed and returned to the research team between November 2016 and August 2018.Results: 184 respondents were included (89 carers, 47 patients aged 4-10 years, 5 aged 11-14 years, 4 aged 15-17 years and 39 > 18 years). Notably, respondents rated social media as the best source of information they have received, even compared with face-to-face consultation with medical professionals. Additionally, only 33% of the respondents had been offered visual impairment support. Notably, patterns of clinical practice and patient experience emerged according to geographical location, particularly provision of initial information and ongoing VI support.Conclusions: This study highlights a significant variation in the support and information received by people in the UK with nystagmus. It also supports the role of charities and increasingly, social media in the provision of patient information. The study also highlights the need for standardized guidelines for the management of patients with nystagmus, particularly with regard to support and information.


Asunto(s)
Cuidadores/psicología , Sistemas de Información en Salud/organización & administración , Nistagmo Patológico/enfermería , Apoyo Social , Baja Visión/enfermería , Adolescente , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Masculino , Nistagmo Patológico/epidemiología , Evaluación de Resultado en la Atención de Salud , Planificación de Atención al Paciente , Calidad de Vida , Encuestas y Cuestionarios , Reino Unido/epidemiología , Baja Visión/epidemiología , Adulto Joven
10.
Eye (Lond) ; 34(9): 1515-1534, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-31919431

RESUMEN

Nystagmus is an eye movement disorder characterised by abnormal, involuntary rhythmic oscillations of one or both eyes, initiated by a slow phase. It is not uncommon in the UK and regularly seen in paediatric ophthalmology and adult general/strabismus clinics. In some cases, it occurs in isolation, and in others, it occurs as part of a multisystem disorder, severe visual impairment or neurological disorder. Similarly, in some cases, visual acuity can be normal and in others can be severely degraded. Furthermore, the impact on vision goes well beyond static acuity alone, is rarely measured and may vary on a minute-to-minute, day-to-day or month-to-month basis. For these reasons, management of children with nystagmus in the UK is varied, and patients report hugely different experiences and investigations. In this review, we hope to shine a light on the current management of children with nystagmus across five specialist centres in the UK in order to present, for the first time, a consensus on investigation and clinical management.


Asunto(s)
Nistagmo Patológico , Trastornos de la Motilidad Ocular , Estrabismo , Adulto , Niño , Humanos , Nistagmo Patológico/diagnóstico , Nistagmo Patológico/terapia , Reino Unido , Agudeza Visual
11.
Eye (Lond) ; 34(12): 2197-2218, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32778738

RESUMEN

Congenital and childhood cataracts are uncommon but regularly seen in the clinics of most paediatric ophthalmology teams in the UK. They are often associated with profound visual loss and a large proportion have a genetic aetiology, some with significant extra-ocular comorbidities. Optimal diagnosis and treatment typically require close collaboration within multidisciplinary teams. Surgery remains the mainstay of treatment. A variety of surgical techniques, timings of intervention and options for optical correction have been advocated making management seem complex for those seeing affected children infrequently. This paper summarises the proceedings of two recent RCOphth paediatric cataract study days, provides a literature review and describes the current UK 'state of play' in the management of paediatric cataracts.


Asunto(s)
Extracción de Catarata , Catarata , Oftalmología , Catarata/terapia , Niño , Humanos , Reino Unido/epidemiología , Trastornos de la Visión/terapia
12.
Eye (Lond) ; 34(9): 1717, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32467640

RESUMEN

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

14.
Eye (Lond) ; 33(2): 261-273, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30353137

RESUMEN

Abnormal eye movements in children, including nystagmus, present a significant challenge to ophthalmologists and other healthcare professionals. Similarly, examination of supranuclear eye movements and nystagmus in children and interpretation of any resulting clinical signs can seem very complex. A structured assessment is often lacking although in many cases, simple clinical observations, combined with a basic understanding of the underlying neurology, can hold the key to clinical diagnosis. As the range of underlying diagnoses for children with abnormal eye movements is broad, recognising clinical patterns and understanding their neurological basis is also imperative for ongoing management. Here, we present a review and best practice guide for a structured, methodical clinical examination of supranuclear eye movements and nystagmus in children, a guide to clinical interpretation and age-appropriate norms. We also detail the more common specific clinical findings and how they should be interpreted and used to guide further management. In summary, this review will encourage clinicians to combine a structured assessment and a logical interpretation of the resulting clinical signs, in order to recognise patterns of presentation and avoid unnecessary investigations and protracted delays in diagnosis and clinical care.


Asunto(s)
Movimientos Oculares/fisiología , Nistagmo Patológico/diagnóstico , Nistagmo Patológico/fisiopatología , Examen Físico , Valores de Referencia , Factores de Edad , Niño , Humanos , Seguimiento Ocular Uniforme/fisiología , Reflejo Vestibuloocular/fisiología
15.
Eur J Surg Oncol ; 32(7): 719-24, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16784834

RESUMEN

INTRODUCTION: The value of special screening for women at moderate breast cancer risk with a family history of breast cancer remains controversial. Little is known about recall rates, false negative outcomes and the impact on clinical service. Despite this, surveillance programmes within breast units have been established in the United Kingdom. PATIENTS AND METHODS: In our institution, screening of women at moderate (lifetime risk, 17-30%) and high risk (>30%) consisted of annual clinical examination and mammography from the age of 35 years. The active study period ran for four months and each patient was followed through a further screening cycle (whole study period), providing information on interval cancers and detection at the subsequent screen. RESULTS: One thousand one hundred and thirty-two women attended for their incident screen: 137 at high risk, 803 at moderate risk and 192 at standard risk. The median age at cancer diagnosis in the moderate risk group was 54 (range, 45-68) years and the high-risk group 51 (46-52) years, compared to 63 (45-69) years in the standard risk group. Seven cancers were diagnosed during the four-month active study period. Two patients were diagnosed with interval cancers and eight at the next screen, giving a cancer incidence in the whole study period of 17/1132 (1.5%). Thirteen patients had invasive cancer and four had ductal carcinoma in situ (DCIS) The median invasive tumour size was 15 had (range, 7-28)mm and the median DCIS size was 4 (2-30)mm. 10/13 (76.9%) invasive cancers were < or =20mm and 2/13 patients (15.4%) with invasive cancer were lymph node positive. The sensitivity and specificity of mammography were 85.7% and 98.8%, respectively. The mammogram recall rate was 27.6 per 1000. The benign to malignant surgery ratio was 8:17. CONCLUSION: Screening women at increased breast cancer risk is effective. Early detection and recall rates are comparable to that of older women attending the British National Breast Screening Programme.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Mamografía , Adulto , Anciano , Neoplasias de la Mama/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , Persona de Mediana Edad , Factores de Riesgo
16.
Eye (Lond) ; 30(9): 1155-9, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27391934

RESUMEN

Refractive correction of aphakia in childhood can be a complex management issue following lensectomy for congenital cataract or ectopia lentis. Some children have inadequate capsular support to allow an 'in the bag' or sulcus fixated intra-ocular lens (IOL). In such cases, options for refractive correction include spectacles, contact lenses, or surgically fixed IOLs. Many methods of IOL fixation have been described, but none are widely adopted in children. In recent years, the iris-fixated Artisan Aphakic IOL has gained popularity, but there is still significant concern about the rate of corneal endothelial cell loss and IOL de-enclavation. Here, we review the current literature on the use of iris-fixated IOLs in children, the published data on endothelial cell loss and de-enclavation rates. We present a case illustrating the significant improvements in quality of life, which can be seen in selected children, and also the rate of endothelial cell loss, which can be encountered after initial surgery, and a re-enclavation event. We make the case that until more data are available on normal endothelial cell decline in early childhood, in addition to age-specific rates of endothelial cell loss and de-enclavation rates following surgery, the use of iris-fixated IOLs in children will continue to be a moot point and is unlikely to be widely adopted.


Asunto(s)
Afaquia Poscatarata/rehabilitación , Extracción de Catarata/métodos , Desplazamiento del Cristalino/cirugía , Iris/cirugía , Implantación de Lentes Intraoculares/métodos , Cristalino/cirugía , Lentes Intraoculares , Afaquia Poscatarata/etiología , Recuento de Células , Preescolar , Pérdida de Celulas Endoteliales de la Córnea/diagnóstico , Pérdida de Celulas Endoteliales de la Córnea/etiología , Endotelio Corneal/patología , Humanos , Masculino , Diseño de Prótesis , Calidad de Vida , Refracción Ocular , Agudeza Visual/fisiología
17.
Metabolism ; 26(6): 637-50, 1977 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-870793

RESUMEN

A 20-yr-old female with congenital lipoatrophic diabetes was studied, with the following findings: (1) Serum insulin levels increased after both oral glucose and intravenous arginine administration; there was no growth hormone response to the latter. (2) The infusion of insulin (0.1 units and 0.5 units/kg) during the fed state and following at 110-hr fast produced only minimal changes of various fuels measured, with the exception of a decrease in the branched-chain amino acids. (3) There was a minimal production of ketones during the 110-hr fast. (4) Matabolic expenditure was markedly increased during the postabsorptive state (65-75 kcal/hr/sg m); it fell into the normal range during the 110-hr fast (31-35 kcal/hr/sq m). (5) Following meals, the patient experienced complaints ranging from cold and shivering to feeling hot with gross diaphoresis. These findings were associated with intermittent lability of her skin temperature, which varied 1 degree - 2 degrees F during a 3-hr period. (6) Progressive increases in doses of regular insulin before each meal resulted in up to a total of 9000 units/day being required before normal blood glucose levels were achieved. (7) A 2-wk therapeutic trial of pimozide provided no significant changes in a variety of hormones and fuels in the basal state or following insulin perturbations. (8) A variety of pituitary hormones and pituitary target organ hormones were studied in both the hypothyroid (Hashimoto's thyroiditis) and euthyroid state (following thyroid replacement). All the hormone responses were normal except that growth hormone did not rise during the slow wave sleep in either thyroid state.


Asunto(s)
Complicaciones de la Diabetes , Lipodistrofia/complicaciones , Adulto , Metabolismo Basal , Glucemia/metabolismo , Temperatura Corporal , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/metabolismo , Ayuno , Femenino , Glucosuria/orina , Hormona del Crecimiento/sangre , Humanos , Hipotiroidismo/complicaciones , Hipotiroidismo/tratamiento farmacológico , Hipotiroidismo/metabolismo , Insulina/sangre , Insulina/farmacología , Insulina/uso terapéutico , Lipodistrofia/tratamiento farmacológico , Lipodistrofia/metabolismo , Pimozida/uso terapéutico , Proteinuria/orina , Hormonas Tiroideas/uso terapéutico
18.
Spine (Phila Pa 1976) ; 16(8): 910-8, 1991 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1948376

RESUMEN

A new spinal instrumentation system for posterior applications was designed with the intent of minimizing intrusion of hardware into the neural canal during and postinsertion. Basic biomechanical measurements of posterior pullout strength led to the establishment of a clamp as an effective mechanism for gaining purchase on the vertebral lamina. These experiments defined the appropriate instrumentation size, as well as establishing that there was no loss of strength with the spinous process removed and the posterior laminar cortex compromised. There was no statistically significant difference between the maximum pullout strength achievable, using a band around the lamina as a control, and that produced by the implant system, in the thoracic spine. Comparative testing of a prototype system in flexion, extension, lateral bending, and torsion showed that the system, in general, had stiffness greater than segmental wiring and less than or equal to Cotrel-Dubousset fixation.


Asunto(s)
Fijadores Internos , Fusión Vertebral/instrumentación , Fenómenos Biomecánicos , Cadáver , Diseño de Equipo , Femenino , Humanos , Vértebras Lumbares/fisiología , Masculino , Persona de Mediana Edad , Escoliosis/cirugía , Estrés Mecánico , Vértebras Torácicas/fisiología
19.
Acta Neurochir Suppl ; 76: 79-80, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11450096

RESUMEN

Experimental data indicate that NMDA receptor activation is strongly implicated in the pathogenesis of cerebral ischaemia. However, the results from in vivo studies are equivocal, with NMDA antagonists being active in only some models. It has recently been demonstrated that competitive and non-competitive NMDA antagonists behave differently under normal and ischaemic conditions. These studies have used organotypic hippocampal slice cultures to investigate whether this disparity is due to redox-modulation of the NMDA receptor which occurs in ischaemia. NMDA-mediated toxicity was concentration dependent with little damage occurring with less than 10 microM NMDA and maximal damage produced by 30 microM. NMDA toxicity was significantly enhanced by pre-treatment with 1 mM dithiothreitol, a reducing agent, such that damage occurred at 1 nM NMDA, and maximal damage was produced by 10 microM. The efficacy of MK-801 was not altered by reducing conditions, but the EC50 of the competitive antagonist APV was increased by 20-fold. These data strongly suggest that the neuroprotective efficacy of NMDA antagonists is significantly altered under ischaemic conditions, and that more beneficial effects will be obtained with antagonists having a higher affinity for the receptor in the reduced configuration.


Asunto(s)
Edema Encefálico/fisiopatología , Isquemia Encefálica/fisiopatología , Hipocampo/fisiopatología , N-Metilaspartato/antagonistas & inhibidores , N-Metilaspartato/fisiología , Fármacos Neuroprotectores/farmacología , Animales , Edema Encefálico/patología , Isquemia Encefálica/patología , Técnicas de Cultivo , Relación Dosis-Respuesta a Droga , Hipocampo/patología , Ratas , Ratas Wistar
20.
J Parasitol ; 61(4): 753-8, 1975 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1165560

RESUMEN

The cuticle of P. crotali is pro-arthropodan, composed of an epi-, exo-, and endocuticle. The exo- and endocuticles are separated by a 600-A intermediate cuticular zone. The epicuticle is homogeneous and varies from 100 to 350 A in thickness. The exocuticle varies from 2 to eight mu in thickness and is divided into superficial and deep exocuticular zones. The endocuticle is lamellate and varies from 8 to 30 mu in thickness. Lamellae result from ordered parabolic orientations of 40-A chitin fibrils. Underlying cells lack a basement membrane. Subcuticular muscle cells insert tonofibrils directly into the adjacent endocuticle. No apodemes or apophyses occur.


Asunto(s)
Arácnidos/ultraestructura , Animales , Arácnidos/clasificación , Piel/ultraestructura , Serpientes/parasitología
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