Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 93
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Philos Trans A Math Phys Eng Sci ; 382(2275): 20230127, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-38910455

RESUMEN

We employ constrained path Auxiliary Field Quantum Monte Carlo (AFQMC) in the pursuit of studying physical nuclear systems using a lattice formalism. Since AFQMC has been widely used in the study of condensed-matter systems such as the Hubbard model, we benchmark our method against published results for both one- and two-dimensional Hubbard model calculations. We then turn our attention to cold atomic and nuclear systems. We use an onsite contact interaction that can be tuned in order to reproduce the known scattering length and effective range of a given interaction. Developing this machinery allows us to extend our calculations to study nuclear systems within a lattice formalism. We perform initial calculations for a range of nuclear systems from two- to few-body neutron systems. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'.

2.
Graefes Arch Clin Exp Ophthalmol ; 261(8): 2301-2305, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36859737

RESUMEN

PURPOSE: We evaluated the pupillary characteristics and response to light and drugs in eyes with posterior chamber (PC) placement of iris-claw intraocular lens (IC-IOL). METHODS: In this cross-sectional, comparative study, we included adults with an IC-IOL implanted in the PC of a single eye. We excluded patients with ocular trauma, postoperative IC-IOL displacement or complications, and extended iris atrophy. We used anterior segment optical coherence tomography to perform light-controlled pupillography, measure the pupil diameter (PD), and estimated the pupil circularity under mesopic conditions. PD was also assessed under photopic, scotopic, pharmacological mydriasis, and miosis conditions. The results were compared to those of the fellow eye, phakic, or regular pseudophakic. RESULTS: The IC-IOL and control groups included 30 eyes each. The most frequent reasons for IC-IOL implantation were complicated cataract (37%) and dislocated/luxated prior IOL (33%). Compared to the control group, the IC-IOL group had lower visual acuity, a smaller PD under scotopic conditions (p = 0.0010) and after pharmacological mydriasis (p < 0.0001), and a larger PD after pharmacological miosis (p < 0.0001). Mesopic pupil circularity was comparable between the groups. We also considered ongoing extraocular treatments with possible effects on iris motility. CONCLUSIONS: The pupillary size and profile were similar between the groups in mesopic light. Reduced mydriasis was noted in response to light and drugs, while the degree of miosis was reduced in response to inducing drugs in the IC-IOL compared to the control group. This study complements previous results concerning the PC placement of IC-IOLs by adding original observations on drug-induced pupil motility.


Asunto(s)
Lentes Intraoculares , Midriasis , Adulto , Humanos , Pupila/fisiología , Implantación de Lentes Intraoculares/métodos , Estudios Transversales , Miosis
3.
BMC Ophthalmol ; 23(1): 433, 2023 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-37880638

RESUMEN

BACKGROUND: Endothelial Keratoplasty (EK) is now considered as the standard treatment for Congenital Hereditary Endothelial Dystrophy (CHED) by many surgeons. We present the 12-year clinical outcome of the youngest operated patient with CHED in which we successfully performed a bilateral EK procedure without removing the recipient endothelium-Descemet complex. CASE PRESENTATION: In November 2010 we performed EK without Descemet Stripping in a 3-month female newborn, thinking that the lower manipulation obtained by leaving the recipient endothelium-Descemet complex could be the key factor for the success of our surgery. Such a particular technique was new in newborns. The surgery was a success, but the long-term visual result was not predictable at that time. We followed the patient at 4 months, and then yearly. At the latest visit in October 2022 the visual, cognitive, and motorial developments were normal, with Best-corrected Distance Visual Acuity of 0.4 LogMAR with - 0.75 D sf + 2.75 D cyl @ 105° in the right eye (RE) and 0.4 LogMAR with + 1.50 D sf + 2.50 D cyl @ 60° in the left eye (LE). The endothelial microscope showed an unexpected healthy endothelium, with a cell count of 2383 cells/mm2 in the RE and of 2547 cells/mm2 in the LE from a starting donor count of 2900 cells/mm2. No secondary procedures were performed during the 12-year follow-up. CONCLUSION: EK without Descemet stripping has proved to be a successful procedure over time in our newborn. The unexpected healthy endothelium suggests a role of the Descemet membrane in CHED.


Asunto(s)
Distrofias Hereditarias de la Córnea , Queratoplastia Endotelial de la Lámina Limitante Posterior , Distrofia Endotelial de Fuchs , Recién Nacido , Humanos , Femenino , Endotelio Corneal , Estudios de Seguimiento , Queratoplastia Endotelial de la Lámina Limitante Posterior/métodos , Agudeza Visual , Distrofias Hereditarias de la Córnea/cirugía , Recuento de Células , Distrofia Endotelial de Fuchs/cirugía , Estudios Retrospectivos , Resultado del Tratamiento
4.
Int Ophthalmol ; 43(9): 3339-3343, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37191929

RESUMEN

PURPOSE: The dynamics of the posterior capsule during femtosecond laser lens fragmentation has received little attention in the literature. We analysed the movements of the posterior capsule to identify the rupture risk factors, if any, and to suggest possible modification of the laser spot energy pattern during fragmentation. MATERIALS AND METHODS: Posterior capsule ruptures during fragmentation were identified over a 10-year period of femtosecond laser use. In addition, the dynamics of the posterior capsule were identified through the real-time swept-source OCT lateral view available during the surgeries. RESULTS: Out of the 1465 laser cataract procedures performed, we recorded 1 case of posterior capsule rupture during lens fragmentation, which was caused by eye movement that was detected but ignored by the surgeon. Three types of posterior capsule dynamics were identified, all related to a gas bubble formation during the first part of the lens fragmentation. In eyes with a hard nucleus, the concussion of the posterior capsule was evident, however, with no capsule rupture. DISCUSSION: Maintaining good docking throughout the whole procedure seems important in avoiding a posterior capsule cut by the femtosecond laser. In addition, a Gaussian pattern of spot energy is suggested when fragmenting hard cataracts.


Asunto(s)
Extracción de Catarata , Catarata , Terapia por Láser , Cristalino , Facoemulsificación , Humanos , Extracción de Catarata/efectos adversos , Terapia por Láser/efectos adversos , Terapia por Láser/métodos , Rayos Láser , Catarata/diagnóstico , Catarata/etiología , Facoemulsificación/métodos
5.
Int Ophthalmol ; 43(5): 1711-1719, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36418805

RESUMEN

PURPOSE: To investigate the advantages/disadvantages of a 1.0 D toric IOL vs spherical IOL after regular phacoemulsification in eyes with preoperative astigmatism ≤ 1 D. METHODS: Retrospective comparative series involving pseudophakic eyes with preoperative topographic astigmatism ≤ 1.0 D implanted either with monofocal 1.0 D Toric IOL (T-group), or with spherical IOL (S-group). The postoperative refractive astigmatism (PRA, i.e. surgically induced + corneal) was the main outcome; also considered in the analyses were the uncorrected and best-corrected distance visual acuity (VA). The data were referred to the last postoperative follow-up visit, 2 to 4 months after surgery. RESULTS: A total of 60 eyes were included: 30 in the T-group and 30 in the S-group, matched for patient's age, laterality, and axial length. Before surgery, the mean corneal astigmatism was 0.62 ± 0.39 D in the T-group and 0.54 ± 0.33 D in the S-group (p = 0.4). In the S-group, PRA was 0.73 ± 0.37 D, higher than the corresponding preoperative corneal astigmatism (p = 0.040). In the T-group, PRA was 0.58 ± 0.31 D; the variation was not statistically significant. Uncorrected VA was significantly better in the T-group vs the S-group (p = 0.007), and the best-corrected VA was comparable in the two groups. CONCLUSION: The present study indicated that in eyes with very low preoperative astigmatism, 1.0 D toric IOLs were able to limit the increase of the PRA instead of those observed with the spherical IOLs. This could support the better uncorrected VA recorded in the T-group.


Asunto(s)
Astigmatismo , Enfermedades de la Córnea , Linfoma Intraocular , Lentes Intraoculares , Humanos , Astigmatismo/cirugía , Implantación de Lentes Intraoculares , Estudios Retrospectivos , Agudeza Visual , Enfermedades de la Córnea/cirugía
6.
BMC Ophthalmol ; 22(1): 233, 2022 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-35606746

RESUMEN

BACKGROUND: Information on the centration and tilt of iris-claw intraocular lenses (IC-IOLs) is limited. In this study, we tested the capacity of an anterior segment optical coherence tomography (AS-OCT) instrument to measure decentration and tilt of anterior and posterior IC-IOLs through an integrated software. METHODS: The present observational, cross-sectional study was conducted at University Eye Clinic of Parma (Parma, Italy). The CASIA2 swept-source AS-OCT (Tomey Corp.) was used to measure the tilt and decentration of posterior and anterior IC-IOLs in patients implanted at least 6 months in advance. After failure with full-automation, semi-manual IOL tracing was applied. In-the-bag (IB) contralateral IOLs, when present, were measured automatically. The Bland-Altman method was used to evaluate the agreement between repeated measurements (2 images for each study eye). The amount and direction of tilt and decentration were recorded and plotted into polar charts for evaluation. RESULTS: A total of 21 patients were included: 14 with posterior and 7 with anterior IC-IOL fixation. In 17 eyes (81%), the AS-OCT provided a repeatable measurement of tilt and decentration. All contralateral eyes with IB IOL were automatically measured. The median decentration was 0.67 mm, 0.24 mm, and 0.24 mm in posterior IC-IOLs, anterior IC-IOLs, and IB IOLs group, respectively. The median tilt was 5.0°, 5.6°, and 5.6° for posterior IC-IOLs, anterior IC-IOLs, and IB IOLs, respectively. Tilt direction was mainly temporal, while decentration was inferior-temporal with posterior IC-IOLs and scattered with anterior IC-IOLs and IB IOLs. CONCLUSIONS: The semi-manual tracing function of the CASIA2 AS-OCT provides repeatable and affordable measurements of the decentration and tilt of IC-IOLs in both the anterior and posterior chamber. Data from the former group were similar to the IB group.


Asunto(s)
Lentes Intraoculares , Tomografía de Coherencia Óptica , Estudios Transversales , Humanos , Proyectos Piloto
7.
Phys Rev Lett ; 126(6): 061101, 2021 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-33635682

RESUMEN

We perform a joint Bayesian inference of neutron-star mass and radius constraints based on GW170817, observations of quiescent low-mass x-ray binaries (QLMXBs), photospheric radius expansion x-ray bursting sources, and x-ray timing observations of J0030+0451. With this dataset, the form of the prior distribution still has an impact on the posterior mass-radius curves and equation of state (EOS), but this impact is smaller than recently obtained when considering QLMXBs alone. We analyze the consistency of the electromagnetic data by including an "intrinsic scattering" contribution to the uncertainties, and find only a slight broadening of the posteriors. This suggests that the gravitational-wave and electromagnetic observations of neutron-star structure are providing a consistent picture of the neutron-star mass-radius curve and the EOS.

8.
Infection ; 49(2): 287-294, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33222020

RESUMEN

Association of renin-angiotensin system inhibitors with risk of death in patients with hypertension (HTN) and coronavirus disease 2019 (COVID-19) is not well characterized. The aim of this study was to evaluate the outcomes of patients with HTN and COVID-19 with respect to different chronic antihypertensive drug intake. We performed a retrospective, observational study from a large cohort of patients with HTN and with a laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection admitted to the Emergency Rooms (ER) of the Piacenza Hospital network from February 21, 2020 to March 20, 2020. There were 1050 patients admitted to the ERs of the Piacenza Hospital network with COVID-19. HTN was present in 590 patients [median age, 76.2 years (IQR 68.2-82.6)]; 399 (66.1%) patients were male. Of them, 248 patients were chronically treated with ACEi, 181 with ARBs, and 161 with other drugs (O-drugs) including beta blockers, diuretics and calcium-channel inhibitors. With respect to the antihypertensive use, there was no difference between comorbid conditions. During a follow-up of 38 days (IQR 7.0-46.0), 256 patients (43.4%) died, without any difference stratifying for antihypertensive drugs. Of them, 107 (43.1%) were in ACEi group vs 67 (37%) in ARBs group vs 82 (50.7%) in O-drugs group, (log-rank test: p = 0.066). In patients with HTN and COVID-19, neither ACEi nor ARBs were independently associated with mortality. After adjusting for potential confounders in risk prediction, the rate of death was similar. Our data confirm Specialty Societal recommendations, suggesting that treatment with ACEIs or ARBs should not be discontinued because of COVID-19.


Asunto(s)
Antihipertensivos/uso terapéutico , Tratamiento Farmacológico de COVID-19 , COVID-19/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Femenino , Humanos , Hipertensión/tratamiento farmacológico , Hipertensión/mortalidad , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , SARS-CoV-2 , Tasa de Supervivencia
9.
BMC Ophthalmol ; 21(1): 196, 2021 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-33941122

RESUMEN

BACKGROUND: To compare parsplana vitrectomy (PPV) with and without phacoemulsification to treat rhegmatogenous retinal detachment (RRD). METHODS: Subjects aged 48-65 years with RRD in a phakic eye due to superior retinal tears with an overall extension of retinal breaks < 90° underwent to PPV alone (group A); or PPV plus phacoemulsification (phacovitrectomy, PCV, group B). Post-operative follow-up visits occurred at 1 week, 1 month (m1), 3 months (m3), and 6 months (m6) after surgery. The main outcome was the rate of retinal reattachment. Secondary outcomes included best-corrected visual acuity (BCVA), intraocular pressure (IOP), central macular thickness (CMT), and cataract progression (in the lens-sparing [PPV-alone] group). RESULTS: In this initial phase of the study a total of 59 patients (mean age: 55 years, 59 eyes) were enrolled: 29 eyes in group A and 30 eyes in group B. Both groups had similar gas tamponade. During the follow-up there were three cases of RRD recurrence in group A and one in group B. The relative risk of recurrence in group A was 3.22 times higher but the difference was not significant (p = 0.3). The two groups were also similar in terms of BCVA and IOP variation. At m3, CMT was significantly higher in group B (p = 0.014). In group A, cataract progression was significant at m6 (p = 0.003). CONCLUSIONS: In a cohort of RRD patients selected according to their preoperative clinical characteristics, PPV was comparable to PCV in terms of the rate of retinal reattachment after 6 months. TRIAL REGISTRATION: ISRCTN15940019 . Date registered: 15/01/2021 (retrospectively registered).


Asunto(s)
Facoemulsificación , Desprendimiento de Retina , Anciano , Humanos , Persona de Mediana Edad , Desprendimiento de Retina/cirugía , Estudios Retrospectivos , Curvatura de la Esclerótica , Agudeza Visual , Vitrectomía
10.
BMC Health Serv Res ; 21(1): 824, 2021 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-34399759

RESUMEN

BACKGROUND: Glaucoma is a disease characterized by progressive damage of the optic nerve. Several therapeutic options are available to lower intraocular pressure (IOP). In primary open-angle glaucoma (POAG) patients with inadequate IOP control (or controlled with multiple medical therapies or for whom medical therapy is contraindicated), the implantation of micro-invasive glaucoma surgery devices (MIGS) and concomitant cataract surgery has proved to be more effective in reducing intraocular pressure (IOP), as compared to cataract surgery alone. The objective of this study was to assess the cost-effectiveness of iStent inject® device with concurrent cataract surgery vs. cataract surgery alone, in patients with mild-to-moderate POAG, adopting the Italian National Health Service (NHS) perspective. METHODS: Simulation of outcomes and costs was undertaken using a Markov model with 4 health states and one-month cycles, that is used to simulate the prognosis of these patients. Efficacy data were obtained from the randomized clinical trial (RCT). A lifetime horizon was adopted in the analysis. A discount rate of 3.5% was applied to both costs and effects. The Italian National Healthcare Service (NHS) perspective was considered, therefore only healthcare direct costs (acquisition of main interventions and subsequent procedures; medications; monitoring and follow-up; adverse events). Model robustness was tested through sensitivity analyses. RESULTS: Results of the base-case analysis showed that the total lifetime costs were higher in the iStent inject® + concurrent cataract surgery, compared with the cataract surgery alone group (€8368.51 vs. €7134.71 respectively). iStent inject® + concurrent cataract surgery was cost-effective vs. cataract surgery alone, with an incremental cost-effectiveness ratio of €13,037.01 per quality-adjusted life year (QALY) gained. Both one-way deterministic and probabilistic sensitivity analyses confirmed robustness of base-case results. The cost-effectiveness accessibility curve (CEAC) showed that iStent inject® + cataract surgery would have a 98% probability of being cost-effective, compared to cataract surgery alone, when the willingness to pay (WTP) is equal to €50,000 per QALY gained. CONCLUSIONS: The results of the cost-utility analysis confirm that iStent inject® + cataract surgery is a cost-effective option for the treatment of patients affected by mild-to-moderate POAG, compared with cataract surgery alone, when evaluated from the Italian NHS perspective.


Asunto(s)
Glaucoma de Ángulo Abierto , Análisis Costo-Beneficio , Glaucoma de Ángulo Abierto/cirugía , Humanos , Presión Intraocular , Italia , Stents
11.
J Med Virol ; 92(11): 2718-2724, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32515500

RESUMEN

Studies have described clinical features of patients with coronavirus disease (COVID-19). However, limited data concerning the clinical characteristics of the Italian deaths are available. We aim to describe the clinical and epidemiological characteristics of 320 deceased from the Italian experience. We retrospectively collected all consecutive non-survivor patients with laboratory-confirmed COVID-19 infection admitted to the Emergency Rooms (ERs) Piacenza Hospital Network during the first month of COVID-19 pandemic in Italy. Clinical history, comorbidities, laboratory findings and treatment were recorded for each patient. A total of 1050 patients with confirmed COVID-19 pneumonia were admitted to the ERs between 24 February and 22 March 2020. Three hundred and twenty (30.5%) patients died with a median age of 78.0 years, 205 (64%) non-survivors were above 65 years old, 230 (71.9%) were male. Non-survivor patients showed frequently several coexisting medical conditions, with hypertension being the most common comorbidity (235 patients, 73.4%). The in-hospital mortality did not change during the progression of the pandemic. In this retrospective Italian study, most of COVID-19 deceased patients were elderly male aged over than 65 years. Hypertension was the most common coexisting disease. In-hospital mortality was high and showed no variation during the first month of the COVID-19 italian epidemic.


Asunto(s)
COVID-19/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Comorbilidad , Femenino , Geografía , Mortalidad Hospitalaria , Hospitalización/estadística & datos numéricos , Humanos , Hipertensión/complicaciones , Hipertensión/epidemiología , Italia/epidemiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo
12.
J Cell Physiol ; 231(9): 1876-93, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-26754581

RESUMEN

The trabecular meshwork (TM) plays an important role in high-tension glaucomas. Indeed, the TM is a true organ, through which the aqueous humor flows from the anterior chamber to Schlemm's canal (SC). Until recently, the TM, which is constituted by endothelial-like cells, was described as a kind of passive filter. In reality, it is much more. The cells delineating the structures of the collagen framework of the TM are endowed with a cytoskeleton, and are thus able to change their shape. These cells also have the ability to secrete the extracellular matrix, which expresses proteins and cytokines, and are capable of phagocytosis and autophagy. The cytoskeleton is attached to the nuclear membrane and can, in millionths of a second, send signals to the nucleus in order to alter the expression of genes in an attempt to adapt to biomechanical insult. Oxidative stress, as happens in aging, has a deleterious effect on the TM, leading eventually to cell decay, tissue malfunction, subclinical inflammation, changes in the extracellular matrix and cytoskeleton, altered motility, reduced outflow facility, and (ultimately) increased IOP. TM failure is the most relevant factor in the cascade of events triggering apoptosis in the inner retinal layers, including ganglion cells. J. Cell. Physiol. 231: 1876-1893, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Humor Acuoso/metabolismo , Citoesqueleto/metabolismo , Glaucoma/metabolismo , Estrés Oxidativo/fisiología , Malla Trabecular/metabolismo , Animales , Citoesqueleto/patología , Matriz Extracelular/metabolismo , Matriz Extracelular/patología , Glaucoma/diagnóstico , Humanos , Malla Trabecular/patología
14.
Ophthalmology ; 122(7): 1283-93, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25972254

RESUMEN

PURPOSE: To assess the safety and effectiveness of the Hydrus Microstent (Ivantis, Inc, Irvine, CA) with concurrent cataract surgery (CS) for reducing intraocular pressure (IOP) in open-angle glaucoma (OAG). DESIGN: Prospective, multicenter, randomized, single-masked, controlled clinical trial. PARTICIPANTS: One hundred eyes from 100 patients 21 to 80 years of age with OAG and cataract with IOP of 24 mmHg or less with 4 or fewer hypotensive medications and a washed-out diurnal IOP (DIOP) of 21 to 36 mmHg. METHODS: On the day of surgery, patients were randomized 1:1 to undergo CS with the microstent or CS alone. Postoperative follow-up was at 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months. Washout of hypotensive medications was repeated at 12 and 24 months. MAIN OUTCOME MEASURES: Response to treatment was defined as a 20% or more decrease in washed out DIOP at 12 and 24 months of follow-up compared with baseline. Mean DIOP at 12 and 24 months, the proportion of subjects requiring medications at follow-up, and the mean number of medications were analyzed. Safety measures included change in visual acuity, slit-lamp observations, and adverse events. RESULTS: The proportion of patients with a 20% reduction in washed out DIOP was significantly higher in the Hydrus plus CS group at 24 months compared with the CS group (80% vs. 46%; P = 0.0008). Washed out mean DIOP in the Hydrus plus CS group was significantly lower at 24 months compared with the CS group (16.9±3.3 mmHg vs. 19.2±4.7 mmHg; P = 0.0093), and the proportion of patients using no hypotensive medications was significantly higher at 24 months in the Hydrus plus CS group (73% vs. 38%; P = 0.0008). There were no differences in follow-up visual acuity between groups. The only notable device-related adverse event was focal peripheral anterior synechiae (1-2 mm in length). Otherwise, adverse event frequency was similar in the 2 groups. CONCLUSIONS: Intraocular pressure was clinically and statistically significantly lower at 2 years in the Hydrus plus CS group compared with the CS alone group, with no differences in safety.


Asunto(s)
Implantes de Drenaje de Glaucoma , Glaucoma de Ángulo Abierto/cirugía , Presión Intraocular/fisiología , Limbo de la Córnea/cirugía , Facoemulsificación , Stents , Adulto , Anciano , Anciano de 80 o más Años , Antihipertensivos/administración & dosificación , Femenino , Estudios de Seguimiento , Glaucoma de Ángulo Abierto/fisiopatología , Humanos , Implantación de Lentes Intraoculares , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Implantación de Prótesis , Método Simple Ciego , Tonometría Ocular , Agudeza Visual/fisiología , Campos Visuales , Adulto Joven
15.
Phys Rev Lett ; 114(9): 092301, 2015 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-25793808

RESUMEN

The onset of hyperons in the core of neutron stars and the consequent softening of the equation of state have been questioned for a long time. Controversial theoretical predictions and recent astrophysical observations of neutron stars are the grounds for the so-called hyperon puzzle. We calculate the equation of state and the neutron star mass-radius relation of an infinite systems of neutrons and Λ particles by using the auxiliary field diffusion Monte Carlo algorithm. We find that the three-body hyperon-nucleon interaction plays a fundamental role in the softening of the equation of state and for the consequent reduction of the predicted maximum mass. We have considered two different models of three-body force that successfully describe the binding energy of medium mass hypernuclei. Our results indicate that they give dramatically different results on the maximum mass of neutron stars, not necessarily incompatible with the recent observation of very massive neutron stars. We conclude that stronger constraints on the hyperon-neutron force are necessary in order to properly assess the role of hyperons in neutron stars.

16.
Anesthesiology ; 123(4): 799-809, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26259137

RESUMEN

BACKGROUND: Both superimposed high-frequency jet ventilation (SHFJV) and single-frequency (high-frequency) jet ventilation (HFJV) have been used with success for airway surgery, but SHFJV has been found to provide higher lung volumes and better gas exchange than HFJV in unobstructed airways. The authors systematically compared the ventilation efficacy of SHFJV and HFJV at different ventilation frequencies in a model of tracheal obstruction and describe the frequency and obstruction dependence of SHFJV efficacy. METHODS: Ten anesthetized animals (weight 25 to 31.5 kg) were alternately ventilated with SHFJV and HFJV at a set of different fHF from 50 to 600 min. Obstruction was created by insertion of interchangeable stents with ID 2 to 8 mm into the trachea. Chest wall volume was measured using optoelectronic plethysmography, airway pressures were recorded, and blood gases were analyzed repeatedly. RESULTS: SHFJV provided greater than 1.6 times higher end-expiratory chest wall volume than HFJV, and tidal volume (VT) was always greater than 200 ml with SHFJV. Increase of fHF from 50 to 600 min during HFJV resulted in a more than 30-fold VT decrease from 112 ml (97 to 130 ml) to negligible values and resulted in severe hypoxia and hypercapnia. During SHFJV, stent ID reduction from 8 to 2 mm increased end-expiratory chest wall volume by up to 3 times from approximately 100 to 300 ml and decreased VT by up to 4.2 times from approximately 470 to 110 ml. Oxygenation and ventilation were acceptable for 4 mm ID or more, but hypercapnia occurred with the 2 mm stent. CONCLUSION: In this in vivo porcine model of variable severe tracheal stenosis, SHFJV effectively increased lung volumes and maintained gas exchange and may be advantageous in severe airway obstruction.


Asunto(s)
Obstrucción de las Vías Aéreas/patología , Obstrucción de las Vías Aéreas/terapia , Ventilación con Chorro de Alta Frecuencia/métodos , Estenosis Traqueal/patología , Estenosis Traqueal/terapia , Obstrucción de las Vías Aéreas/metabolismo , Animales , Porcinos , Estenosis Traqueal/metabolismo , Resultado del Tratamiento
17.
Eur J Ophthalmol ; 34(1): NP138-NP143, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36862592

RESUMEN

PURPOSE: To describe the unexpected one-year course of a probable Tobacco Alcohol Optic Neuropathy (TAON) and the unprecedented Laser Speckle Flowgraphy (LSFG) assessment. CASE REPORT: A 49-year-old Caucasian man with no family history of visual impairment referred because of unilateral and painless visual acuity (VA) decrease in the right eye (RE). Also, color vision and visual evoked potentials were unilaterally altered. Optical coherence tomography (OCT), instead, revealed bilateral thinning of the macular ganglion cell inner plexiform layer. Funduscopy, intraocular pressure, pupillary shape/reactivity and ocular motility were normal. Blood testing revealed macrocytic/normochromic anemia and low levels of vitamin B2 and folic acid. The patient admitted heavy tobacco and alcohol intake for many years. After an initial compliance to the prescribed regimen, the patient quitted the vitamin intake and resumed his smoking and drinking habits. After a 13-month follow up the VA further reduced in the RE; the fellow eye preserved normal visual function despite the bilateral and progressive alterations of the OCT assessment. Both eyes underwent LSFG examination. All the conventional nets evaluated by the instrument (i.e., Mean Tissue, Mean All and Mean Vascular perfusion) were lower in the RE. CONCLUSIONS: Based on patient's behavior, visual deficiencies and laboratory findings, we assumed that the patient suffered from TAON. Also after one year, however, a deep discrepancy between the strictly unilateral, progressive VA impairment and the bilateral, symmetrical OCT alterations persisted. The LSFG data clearly indicate that the perfusion of the two eyes differed, especially referring to tissular vascularization in the optic nerve head area of the RE.


Asunto(s)
Potenciales Evocados Visuales , Enfermedades del Nervio Óptico , Masculino , Humanos , Persona de Mediana Edad , Estudios de Seguimiento , Enfermedades del Nervio Óptico/diagnóstico , Enfermedades del Nervio Óptico/etiología , Nervio Óptico , Tomografía de Coherencia Óptica , Rayos Láser
18.
Eur J Ophthalmol ; 34(1): NP104-NP107, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37424299

RESUMEN

PURPOSE: Herein we describe the change in the amount of macular oedema in one eye after contralateral intravitreal brolucizumab injections in a patient with neovascular age-related macular degeneration (nAMD). CASE REPORT: A patient with bilateral nAMD underwent intravitreal bevacizumab injections in both eyes with little improvement in the best-corrected visual acuity (BCVA) and central macular exudation. The treatment was switched to aflibercept, but there was incomplete drying of the macula in both eyes. After uneventful cataract extraction, the central macular thickness (CMT) increased markedly in the operated left eye (LE), which was unresponsive to subtenon triamcinolone and further intravitreal aflibercept. Cataract surgery was also performed in the right eye (RE) combined with an intravitreal sustained-release dexamethasone implant. Nevertheless, the CMT increased. Intravitreal brolucizumab injections were performed in the RE with almost complete disappearance of the oedema in the treated eye. Concurrently, the contralateral uninjected eye showed a remarkable decrease in CMT. Five months after the first brolucizumab injection, the macular exudation increased again in both eyes. A second brolucizumab injection was performed in the RE only, and was followed by a prompt reduction in CMT in both the injected RE and uninjected LE. CONCLUSIONS: Although contralateral retinal changes have been described for many other vascular endothelial growth factor inhibitors, there is little evidence for brolucizumab. We describe a repeated dose- and time-related effect on the uninjected eye in a case of nAMD.


Asunto(s)
Degeneración Macular , Degeneración Macular Húmeda , Humanos , Inhibidores de la Angiogénesis/uso terapéutico , Factor A de Crecimiento Endotelial Vascular , Anticuerpos Monoclonales Humanizados/efectos adversos , Receptores de Factores de Crecimiento Endotelial Vascular , Degeneración Macular/tratamiento farmacológico , Inyecciones Intravítreas , Proteínas Recombinantes de Fusión , Degeneración Macular Húmeda/diagnóstico , Degeneración Macular Húmeda/tratamiento farmacológico
19.
Acta Ophthalmol ; 102(2): e140-e155, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37350260

RESUMEN

Glaucoma is currently considered one of the leading causes of severe visual impairment and blindness worldwide. Topical medical therapy represents the treatment of choice for many glaucoma patients. Introduction of latanoprost, 25 years ago, with an entirely new mechanism of action from that of the antiglaucoma drugs used up to that time was a very important milestone. Since then, due mainly to their efficacy, limited systemic side effects and once daily dosing, prostaglandin analogues (PGAs) have become as the first-choice treatment for primary open-angle glaucoma. PGAs are in general terms well tolerated, although they are associated with several mild to moderate ocular and periocular adverse events. Among them, conjunctival hyperemia, eyelash changes, eyelid pigmentation, iris pigmentation and hypertrichosis around the eyes are the most prevalent. The objective of this paper is to review the role of PGAs in the treatment of glaucoma over the 25 years since the launch of Latanoprost and their impact on clinical practice outcomes.


Asunto(s)
Glaucoma de Ángulo Abierto , Glaucoma , Hipertensión Ocular , Prostaglandinas F Sintéticas , Humanos , Latanoprost/uso terapéutico , Glaucoma de Ángulo Abierto/tratamiento farmacológico , Prostaglandinas F Sintéticas/uso terapéutico , Antihipertensivos/uso terapéutico , Glaucoma/tratamiento farmacológico , Prostaglandinas Sintéticas/uso terapéutico , Hipertensión Ocular/tratamiento farmacológico , Presión Intraocular
20.
J Clin Med ; 13(2)2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38256642

RESUMEN

BACKGROUND AND OBJECTIVES: This study aimed to evaluate the effect of cataract extraction on intraocular pressure at 6, 12, and 24 months and their difference compared to the baseline in diverse glaucoma subtypes. MATERIALS AND METHODS: We carried out research in the MEDLINE, Cochrane Library and EMBASE databases, as of April 2022 for relevant papers, filtered according to established inclusion and exclusion criteria. The meta-analysis evaluated the Mean Reduction and relative Standard Error in these subpopulations at predetermined times. A total of 41 groups (2302 eyes) were included in the systematic review. Due to the significant heterogeneity, they were analysed through a Random Effects Model. RESULTS: We obtained these differences from baseline: (1) Open Angle Glaucoma at 6, 12 and 24 months, respectively: -2.44 mmHg, -2.71 mmHg and -3.13 mmHg; (2) Angle Closure Glaucoma at 6, 12 and 24 months, respectively: -6.81 mmHg, -7.03 mmHg and -6.52 mmHg; (3) Pseudoexfoliation Glaucoma at 12 months: -5.30 mmHg; (4) Ocular Hypertension at 24 months: -2.27 mmHg. CONCLUSIONS: Despite a certain variability, the reduction in ocular pressure was statistically significant at 6, 12 and 24 months in both Open Angle Glaucoma and Angle Closure Glaucoma, the latter being superior. Data for Pseudoexfoliation Glaucoma and for Ocular Hypertension are available, respectively, only at 12 months and at 24 months, both being significant.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA